DE19927740A1 - Preparing an agent for diagnosis or control of microbial infection, useful particularly against Helicobacter, based on identification of essential genes in defective mutants - Google Patents

Abstract

Preparation of an agent (A) for detection, prevention and/or treatment of microbial infection by: (i) identifying essential genes (I) and corresponding polypeptides (II); (ii) identifying compounds that are directed against (II) and inactivate the microbe; (iii) testing these for suitability for use; and (iv) formulating selected (A). Identifying essential genes (I) comprises preparation of gene-deficient microorganisms by conditional antisense inhibition (CAI) and/or subtractive recombination mutagenesis (SRM), then determining viability and/or survival of the deficient organisms. Independent claims are also included for the following: (a) method for identifying essential microbial genes; (b) nucleic acid (Ia) representing essential secretory genes of Helicobacter, identified by method (a); (c) a gene bank containing at least two (Ia); (d) a vector containing at least one (Ia) or its fragment; (e) cells containing (Ia) or the vector of (d); (f) a mutant bank containing at least two microorganisms transformed with the vectors of (d); (g) a polypeptide (IIa) encoded by (Ia) and their immunogenic fragments; (h) inhibitors (A') that bind specifically to (IIa), or its fragments, and/or modulates its expression, presentation and/or native function; (i) method for preparing (IIa) or its fragments; (j) antibodies (Ab), or their fragments, that are specific for (IIa); and (k) a pharmaceutical composition containing one of (Ia), the vector of (d), the cells of (e), (IIa), Ab or its fragments, or (A).

Description

The present invention relates to a method for identification and Characterization of essential genes of pathogenic microorganisms, their Use to find new immunological and pharmacological Active substances for the prophylaxis, therapy and diagnosis of bacterial infections, as well as the further development and optimization of these active ingredients. Of the The invention includes the corresponding nucleic acids, which encode the essential gene products, and encode them Polypeptides. In addition, the invention relates to vectors that Contain nucleic acids according to the invention with these vectors transformed cells and antibodies specific for the polypeptides. This Nucleic acids and polypeptides can be used for diagnosis, prevention and Treatment of microbial infections can be used, in particular can use them to develop antibodies, vaccines and inhibitors be used.

The complete molecular development of the human genome and clinically relevant pathogens opens new avenues in the development of Therapeutics or prophylactics against human diseases. So is the decoding of the human genome for years to come announced. The number of molecularly fully characterized pathogens Germs are constantly increasing. The declared goal is now from the extensive data material to identify such genes, their products as a potential target for an active ingredient and thus for the Development of a specific active ingredient can be used. This  Potential cannot be derived from the primary structure of a gene, but rather must be determined experimentally.

When the complete genomic sequence of an organism is available, one stands facing the problem of the enormous amount of data for advanced biological Make analyzes accessible. The first step is identification all genes on the genome. This is usually done with the help computer-aided search programs with a certain security can predict potential genes. This way, gene cards can are created, which are still subject to great inaccuracy are. Can the genes identified by the search program none known gene must be assigned the functionality of this hypothetical genes through the physical detection of the gene products can be detected in the original cell.

Another strategy that is also based on the application of special Search programs is based on the identification of possible gene families aligned with specific biological properties, which in turn is considered as an active ingredient target based on further assumptions come. The search criteria are based on characteristic structural features aligned, which are usually derived from already known genes were. The result of such a search can, depending on the Approximation of the specifications for the real condition, a high hit rate deliver. However, the inaccuracy of these methods is usually relative high, and the real biological property of the gene or its In any case, the gene product must be confirmed experimentally.

Another strategy captures the expression products of a cell, thereby the genes active for the respective state of development are identified can. If you compare different development stages with each other, the interaction of the genes can be derived in this way and in some cases, the biological function of unknown genes can be partial  be decrypted. Appropriate comparative studies are carried out through with cells that have a pathological appearance, it is it is even possible to identify disease-causing genes and use them as potential drug targets for drug development.

All of the methods described serve in particular to hitherto unknown Identify genes and use computer-assisted ones To assign data comparisons to a biological function. A clear one Evaluation of a gene or gene product with regard to its potential as Serve drug target and thus for the development of drugs Being able to be used, however, does not meet any of the known Method.

Some of the most important requirements for a pathogenic organism, Surviving in a host and multiplying are, on the one hand, the Ability to escape the host's immune system, and on the other hand, the Ability to adapt to a very specific habitat or niche. The factors and proteins responsible for this are therefore usually essential for the pathogenic germ.

It would be of great advantage to have these essential genes from microorganisms to identify in this way the ability to manufacture therapeutic, preventive and / or diagnostic agents, e.g. B. Antibodies, vaccines or inhibitors of the corresponding polypeptides to get.

Helicobacter is a pathogen of particular medical interest pylori. This germ is a gram-negative, spiral-shaped bacterium high pathogenic potential, which has increased in recent years Resistance to a number of therapeutically relevant antibiotics has developed and is therefore of great clinical importance. It draws themselves through extremely high mobility due to its flagella and the  unusual ability in the strongly acidic environment (up to pH 1.5) of the stomach survival from (Goodwin et al., 1989).

Although the appearance of spiral bacteria in the human Gastric mucosa has long been known, has only been known since successful isolation and cultivation of this bacterium (Warren and Marshall 1983; Marshall et al., 1984) from the gastric mucosa of a Patients with a gastric ulcer (ulcer ventriculi) that this is are pathogenic germs. H. pylori infection is one of the most common chronic human bacterial infections. It occurs worldwide about 50% of the population are infected with this bacterium.

Infection inevitably causes bacterial gastritis (Type B gastritis) in humans. It is also assumed that H.pylori also a causal role in the development of gastric and Duodenal ulcers (Ulcus ventriculi and Ulcus duodeni) as well as in some forms of gastric carcinoma (adenocarcinoma) (Lee et al., 1993; Solnick and Tompkins, 1993). In two studies from 1991, one statistically significant correlation between H.pylori infection and Occurrence of gastric carcinoma (intestinal type) is shown, both Studies have concluded that approximately 60% of all occurring Gastric carcinomas are likely due to H. pylori infection (Parsonnet et al., 1991; Nomura et al., 1991). Even the less common Occurring MALT (Mucosa Associated Lymphoid Tissue) lymphomas of the Stomach, which acts as a precursor to B-cell tumors of the immune system are probably a result of the H.py/ori infection. A The consequence of long-term infection with H. pylori is atrophic gastritis, one Degeneration of the mucus, acid or pepsin producing cells of the Gastric epithelium, which must be viewed as a precancerous lesion.

After the oral intake, the bacteria first get into the extreme acidic stomach lumens (pH 1 to 2). There is through the production of the enzyme  Urease, which is used to cleave the existing urea and thus to local Neutralizing the acidic pH in the stomach leads to survival which enables bacteria. Using chemotactic orientation and The germs then move into the Bicarbonate-buffered mucus layer of the antral region of the stomach, its actual natural habitat. There they are in a unique ecological niche, due to the acid barrier only for a few competing bacterial species is accessible. They are probably oriented Bacteria at the pH gradient between lumens (pH 1-2) and Epithelial cell surface (pH 6-7) to get to the epithelium. Through her spiral shape, its mobility in viscous mucus, the production of Mucus-modifying enzymes and finally through a microaerophile These germs are optimal to the living conditions in this way of life Habitat adapted. They mostly stay in the deep crypts of the antrum Region where they are protected from external influences such as B. acid, but also pepsin before drugs for their eradication, such as. B. antibiotics are protected. Part of the bacterial population (approx. 20%) is closely related to epithelial cells associated, especially with mucus producing cells. Under the Prerequisite for gastric metaplasia, d. H. of acid-induced Formation of gastric epithelium in the duodenum, there is also Colonization of metaplastic areas in the duodenum, causing the Requirements for the development of the duodenal ulcer (ulcer duodeni) are created. Because of their ability to be adherent, presumably a complete elimination of the Helicobacter with the rejected Slime prevents the bacteria from going for years, decades or even Can persist for life (chronic infection).

Before the existence and significance of H. pylori for ulcer diseases were known, they were treated by so-called antacids or H ₂ receptor antagonists. These are substances that inhibit acid secretion of the gastric parietal cell. Under the influence of these medicinal products, ulcers usually heal, but since one of the causes of these ulcers, namely H. pylori infection, is not eliminated so that in most cases the ulceration reappears after a short time (Relapse).

Another therapy often used for ulceration is bismuth Treatment. Different bismuth salts (CBS, BSS) have one bactericidal effect on H. pylori. A major disadvantage of this Therapy is, however, that a total eradication of the germ in only one very low percentage of cases is reached (8 to 32%). As with the Treatment with antacids is temporary Suppression of the germ, and after treatment is discontinued in the in most cases the infection flares up again. Another disadvantage The bismuth treatment is that longer lasting therapy with high Doses to accumulate this substance in the liver, kidney and Nervous system and has considerable neurological side effects (Malfertheiner, 1994).

Since the realization that it is gastroduodenal Ulcer diseases are infectious diseases Treatment now also uses antibiotics. The monotherapy with various antibiotics (amoxicillin, nitrofuran, furazolidin, erythromycin and the like), however, turned out to be unsatisfactory since it here too only for 0 to 15% of the cells for complete eradication of the Germ comes. The most successful treatment so far is currently one Combination of an acid blocker (ompeprazole) with an antibiotic (Amoxicillin) reached, which can lead to eradication rates up to 80% (Malfertheiner, 1994). In the long run, antibiotic treatment is necessary Elimination of H.pylori is not promising, however, because of the incomplete eradication of the germ with rapid resistance development of the bacteria against antibiotics must be expected.  

The increasing appearance of antibiotic resistance and the restricted treatment options, which are usually substantial Having unwanted side effects makes finding new ones Forms of therapy and in particular the identification of new active substances necessary, especially vaccines, both prophylactic, as well therapeutic treatment of Helicobacter infections can be. The pharmaceutical form is also of particular interest, since the active ingredient in the stomach, i.e. H. effective in an extremely acidic environment have to be. Connections with proton blockers, e.g. B. before Administration of the prophylactic or therapeutic agent can be of great benefit.

The molecular basis for persistent, chronic Helicobacter Infections have not yet been resolved. It could be shown that the factors urease, mobility and adherence essential properties of the bacteria are able to colonize the gastric mucosa.

Although the host organism is unable to function under normal conditions is coping with an H. pylori infection was shown in the animal model, that urease, an essential virulence factor of H. pylori, is high Has potential as a vaccine (US patent application US-SN-07 / 970,006 "Urease-based Vaccine Against Helicobacter Infection).

However, the components that are responsible for ensuring that the So far pathogens that can bypass the host's immune system are still unknown.

Pathogenic organisms in general have a variety of strategies developed in the host over a long period of time by the immune system to be able to persist undisturbed (Haas and Göbel, 1992; Finlay and Falkow, 1997). A mechanism to survive in hostile to life Serving milieu is the formation of a form of persistence.  

In the case of H.pylori, coccoid forms have been described several times as potential forms of persistence, but their clinical significance is controversial. Coccoid forms could play a major role in ex vivo survival. With regard to in vivo survival, it has been shown that coccoid forms are preferred due to an unfavorable environment such as e.g. B. a high O ₂ partial pressure or sublethal administration of antibiotics (bismuth subcitrate, erythromycin, amoxicillin, metronidazole) can be induced (Donelli et al., 1998; Bode et al., 1993; Sorberg et at, 1996; Berry et al ., 1995).

Some researchers assume that these coconut-like bacteria are viable but not cultivable (VNC, viable but non-culturable). Eaton and co-workers got a successful infection from mini Piggy with vegetative (spiral) H. pylori, while coconut Forms in this model showed no infection (Eaton et al., 1995). The direct detection of coccoid forms in the human stomach has been reported by Chan et al. based on gastric tissue sections from biopsy material rendered. In 82.8% (53/64) of the examined biopsy samples the Authors demonstrate coccoid forms of H. pylori (Chan et al. 1994). By Cao et al. became a monoclonal antibody specific Detection of coccoid H.pylori used in tissue sections. Here too in addition to the vegetative forms, 100% of the antrum biopsies (9/9) H. pylori coccoid forms detected (Cao et al., 1997).

Binding to epithelial cells and signal transduction ability (IL-8- Induction, rearrangement of the cytoskeleton, binding of plasminogen, Lactoferrin and Vitronectin on the bacterial surface) appears Cocooid forms comparable to the vegetative forms to be preserved (Khin et al., 1996; Segal et al., 1996).

The above experiments indicate a coconut meaning Forms for the survivability of Helicobacter in an unfavorable environment  there. Hence the identification of genes associated with the genesis of this Form and reactivation are related to the vital form for which Development of new active substances of great interest.

In addition to Helicobacter pylori, other Helicobacter species can also Colonize human stomach such as B. H.heilmannii and H, felis. In this regard it could be shown that H.hellmannii with pathological ulcer diseases can be associated. The causal transmission probably takes place from pets to the People instead. So far, has been the most common in humans H.pylori suspected of having gastric cancer To play role. There are now clinical data to support this To question the connection. These doubts are particularly noticeable by newer ones Data supported by Helicobacter Heilmannil, this one a larger one attach carcinogenic potential and its importance in Highlight the development of gastric MALT lymphoma (Regimbeau et al., 1988).

Taking a summary of what has been said so far, it is clear that a Need for new forms of therapy to combat bacterial Pathogens, especially after vaccines and inhibitors of essential genes or their expression products. The increasing resistance to a variety of proven Medicines require continuous supply of new ones Active substances. This increasing need for new active ingredients can only are covered when new drug targets are identified and these are used Development of new active ingredients can be used. Essential genes are an ideal target for drug development because they are for Survival of the pathogen is necessary.

The identification of essential genes of Helicobacter, especially of H.pylori or heilmannii and of possible Helicobacter  Persistence forms for the development and optimization of new ones therapeutic, preventive and / or diagnostic agents, such as. B. Vaccines and pharmacological agents are therefore a goal of Invention is in the foreground is the discovery of essential microbial Genes, including homologous proteins from various pathogenic germs can be identified. With the help of an active ingredient could then as with classical antibiotics eliminated several pathogenic germs at the same time become. Helicobacter focuses in particular on genes that fulfill vital functions in the infection process, as well as genes that are involved in the development and reactivation of coccoid forms. Of particular interest here are essential genes that are secreted Encode gene products because they are immunological and pharmacological Active ingredients particularly well achieved due to their exposed location can be and are therefore good candidates for drug development. Also of interest are essential genes that code for gene products, involved in the development and maintenance of Persistence forms are involved. Another task is to find it essential microbial genes, including homologous proteins of various pathogenic germs can be identified. With the help of an active ingredient could then, as with classic antibiotics, several pathogenic germs be eliminated at the same time.

This object is achieved by a method for providing means for the detection, therapy and / or prevention of microbial infections, which comprises the following steps:

• A) Identify essential genes and the corresponding ones Polypeptides by producing gene deficient microorganisms conditional antisense inhibition (CAI) and / or subtractive Recombination mutagenesis (SRM) and determination of life and Survivability of the gene-deficient microorganisms in one Test system.  
• B) Identifying specific active substances that are against the essential polypeptides are directed and the inactivation of the Bring microorganisms or used microorganisms.
• C) Testing the identified active ingredients for their applicability as Components of diagnostic, preventive or / and therapeutic agents,
• D) Formulating the applicable active ingredients as diagnostic, preventive or / and therapeutic agents.

The procedure presented here deals with identification essential genes and their use in the development of new drugs.

Another aspect of the present invention is thus also a method for identifying essential microbial genes, which comprises the following steps:

• a) production of gene-deficient microorganisms,
• b) determining the viability and / or survivability of the gene-deficient microorganisms from (i),
• c) Identifying a protein coding section of a microbial DNA sequence in which the deficient microorganisms are defective are and
• d) Characterize those DNA segments that are essential for the Are viability.

CAI is short for "conditional antisense inhibition". H. conditional antisense inhibition. It is a process which is described in more detail below.

SRM stands for "subtractive recombination mutagenesis", d. H. subtractive Recombination mutagenesis and is also described below.  

The term "gene deficient" as used herein means that the deficient organism is unable to use one or more of its To produce gene products or to use their function. The production of the corresponding gene product can on the one hand by mutagenesis of the corresponding gene can be prevented or there may be inhibition take place during expression, e.g. B. by antisense nucleic acids. Mutagenesis can be used to find a gene in the genome of the Microorganism to mutate, or to insert a mutated gene in the Introduce microorganism, taking into account the homologous Can take advantage of recombination.

A protein coding section of a nucleic acid sequence is for example a gene or part of a gene that expresses a polypeptide allowed.

The term "essential gene" means a gene that is responsible for a gene product encodes, without which an organism cannot survive or only is limited survivable. Essential genes can fall into two classes are divided into: obligatory essential and optional essential genes. On obligatory essential gene encodes a protein that is essential for survival or the reproduction of an organism is essential under all circumstances. In contrast, an optional essential gene codes for a protein that only under certain conditions for survival or the Propagation of the organism is necessary, such as. B. the ability of Organism, within cultured mammalian cells or in animals too to survive. In both cases, the survival or the multiplication of the Organism by inactivating a gene that is essential for it or the Inhibition of a gene product essential for him is severely impaired or prevented. Is a bacterium after inactivating a specific gene no longer viable or limited in reproduction, can this should be regarded as the first indication that this gene essential properties are conveyed. The significance of such  Findings must, however, be underpinned by accompanying control experiments be, e.g. B. should such a lethal mutation in a second step by corresponding complementation of the gene or gene product can be canceled. Essential genes are those that their non-expression or absence, e.g. B. by mutagenesis or deletion means that the organism is neither in a natural state Environment, still ideal on the needs of the microorganism coordinated full medium is viable. Is a microorganism in one facultatively essential gene deficient, it is usually on one depending on the organism defined full medium is still capable of growth however in a natural environment, i.e. H. in its natural host or cells or tissue cultures of its natural host no longer survive.

Identify essential genes

The new process can be used regardless of their special function essential genes of microorganisms can be identified. Is preferred this procedure for the identification of essential genes from Helicobacter and related microorganisms.

In a first step, the complete genome of a bacterial Pathogens with a molecular genetic approach based on essential Genes searched. This sub-step does not require any knowledge of the Primary structure of the genome or individual genes, but takes place exclusively based on biological criteria. is a gene as essential Identified determinant, its identity is determined. This can be done on the determined raw sequence data of the genomic sequencing be resorted to. Based on the gene sequence determined z. B. isogenic variants are determined or whether the gene found is in one Operon is in which there may be other essential genes are located.  

In a second step, the identified genes are broken down into special ones transferred genetic systems that serve the genes or their To deliver gene products to a direct drug screening and / or the Genes or gene products used to identify previously identified active substances further optimize. The main advantage of the overall process is based on the rapid successive execution of the gene and active ingredient Screenings in meaningful biological systems, so that in relative short time from the complete gene set of a pathogenic microorganism identifies the potential drug targets, produces them and directly to them Drug screening or optimization can be used.

If a microorganism is examined, its genome already is sequenced, the identification of a gene or gene segment with With the help of database analyzes, one sequence section Reading frame is assigned. Preferably, however, regardless of Presence of a complete genome generation any gene bank be subjected to a preselection. In this case, the Preselection for genes to be carried out for polypeptides with a encode certain function, for example using Homology analysis. The preselection can also be carried out on genes that are only expressed in certain stages of development.

In the first sub-step, a strong one can be selected Reduction of the genetic material to be examined can be achieved. E.g. by an enrichment step for genes that are for exported or secreted Encode gene products. In this special procedure, the DNA Sections of a gene bank mutagenized by a pathogen, what for example by cloning such a DNA segment into a Plasmid, transformation into a preferably heterologous host organism and subsequent mutagenesis can take place. The resulting Expression product can then be detected. Mutagenesis can for example by inserting a marker sequence, which at  Expression of the mutagenized sequence in a host organism Fusion polypeptide leads to which can be selected. The insertion of the Marker sequence is not limited to transposon insertion, but can can also be done in other ways, for example by homologs Recombination or infection and recombination with the help of Bacteriophages.

The marker sequence used in the sense of the present invention is in generally a gene that encodes a gene product that has a selection on it allowed those host organisms that express this sequence. in the in general, these marker sequences are resistance genes, which confer resistance to certain antibiotics, or which ones Allow host organism to survive in a selection medium. The Genmarker preferably does not have its own expression signals, but is directly dependent on an upstream promoter, such as. B. the Transcription promoter on the promoter segment or a promoter that lies on the cloned heterologous DNA fragment to be identified. As an alternative to antibiotic resistance marker sequences, enzymes can also be used as Gene markers can be used. In these cases, the successful one Insertion indicated by a certain color reaction, which is manual Isolation of the corresponding bacterial clone allowed.

If the marker sequence as a fusion protein with the expression product of the inserted DNA fragment is expressed and a selection as above described, DNA material can be selected from the selected Bacterial clones are isolated and the DNA sequence required for that Fusion product coded, determined by known methods. This allows the assignment of a reading frame to the DNA to be identified Fragment. It is then possible to carry out comparative studies with generally available ones DNA sequence databases to determine the identity of the clarified identified gene and possibly indications of a to achieve biological function.  

Through technical and further additions to the two shown below Procedure, CAI and SRM, can be a targeted reduction of the Sample volume can be reached. It is also about upstream selection procedures that target specific gene groups, e.g. B. the use of subtractive libraries of pathogenic and non-pathogenic Representatives. Here, pathogenicity-mediating gene areas enriched. Such subtraction methods can also be used to identify genes specific to certain organisms for example, by comparing and subtracting the genomes from H.pylori and H.heilmannii.

In other processes such. B. gene groups can be identified that only can be expressed in a specific development step.

The array method, in which the individual gene samples of the pathogen in a grid on a carrier be applied. The individual order points are known, so that with a positive hybridization reaction with the development-specific Transcription products or cDNAs or subtractive cDNAs or Fragments thereof, the respective genes identified and then cloned can be. Other methods, the development-specific gene groups are comparative proteome and differential display analyzes.

To find out whether the identified gene sequences are essential genes, microorganisms are produced, which in the sequences are deficient which correspond to the identified gene sequences correspond. The deficient microorganisms are then on different growth media or cell cultures or in animal models or tested in the natural host, and the deficient genes can then vary depending on Viability of a category of non-essential, mandatory essential or optionally essential genes are assigned.  

On the importance of genes, which the development from the vital into the Controlling the form of survival and vice versa is already at the beginning been pointed out. It is therefore particularly preferred to carry out a preselection to perform on such genes. Methods such as CAI or SRM can be applied and the gene-deficient microorganisms then be examined on certain nutrient media that are transitioning trigger from one form to the other. At Helicobacter is special preferred the Schivo medium, which reactivates the coccoids Form into the vital spiral form.

Deficient microorganisms can be produced in several ways respectively.

There are a number of molecular genetic methods available to mutagenize the genome of a bacterial pathogen so that there is a mutant available for each gene. The most common Mutagenesis method is based on the inactivation of genes, e.g. B. by Transposons inserting randomly in the genome using appropriate markers be selected. There are numerous variations for this process, that can be applied to different organisms. (Joyce and Grindley, 1984; Akerley, et al., 1998). With the help of the advertised The mutagenized gene can also be transposons precisely in the genome locate.

You have a mutant gene with a demonstrable biological effect generated, e.g. B. reduced growth of cells in a particular Milieu, so in a second step, the clear coupling of the gene or the gene product with this property can be detected. This usually happens through complementation experiments. In this case becomes the original in the organism with the specific mutant gene Gene introduced and expressed. Can the original over this way The organism's ability to be regenerated is the necessary proof  rendered. However, this method cannot be used for Apply characterization of lethal mutants, d. H. obligatory for mutants essential genes. One way out is to use conditional Mutations for complementation. For example, chemical Mutagenesis of the gene under investigation temperature-sensitive mutants generate the gene product at the normally optimal Bring growth temperature into an inactive state and at produce a biologically active gene product at lower temperatures (Das, et al., 1976; Harris, et al., 1992; Hou, et al. 1994; Polissi and Georgopoulos, 1996). In another practiced approach, the wild-type complementations by exogenous substances, so-called. Controlled inductors. The expression of the complementing gene turned on on an episome in the gene-specific mutant is introduced and the missing after induction Gene product replaced (Murphy, et al., 1995-. Chow and Berg, 1988; Arigoni, et al., 1998).

The above procedures are very time consuming and are only for the Examination of individual genes or limited genomic sections used. Procedures that consistently characterize a complete, mutagenized library of a selected pathogen enable according to the scheme described are not yet known.

The new genetic processes described below that Conditional antisense inhibition (CAI) and the subtractive Recombination mutagenesis (SRM) meet these requirements. Both Methods can be used to identify essential genes the CAI procedure is particularly mandatory for identification essential genes and the SRM method for facultatively essential Genes.  

The CAI method is based on the conditional inhibition of translation of one or more genes that are on a cloned genome fragment (which then serves as a template or template) and via a plasmid are propagated in the germ to be examined. Compared to conventional genomic structure remains the same investigating germ unchanged, d. H. in original condition. Im too investigating germ is the inhibition of translation by the conditionally inducible synthesis of specific antisense RNA (asRNA) triggered, which includes the complete cloned genome fragment, including the genes located on the genome fragment. The antisense Nucleic acid sequences can then be found in large quantities in the microorganism are synthesized and bind to the original mRNA, this being mRNA can no longer be translated and thus the Expression apparatus is withdrawn. The result is that either none Genetic product or only small amounts of it are formed. The synthesis the asRNA is controlled by a promoter (asPromoter), its activity conditionally controlled by defined external signals becomes. This conditional inhibition of the expression of a gene or operon thus takes place via the regulation of the synthesis of the asRNA by the inducible asPromoter. To prove that a gene or operon, such as in the present case, for the survival and reproduction of the organism is essential under certain conditions, the survival and Propagation rate of a clone in which the synthesis of the asRNA is induced, with its survival / multiplication rate with uninduced asRNA Compared synthesis. Is the survival / reproduction rate of the clone at Induction of asRNA synthesis is reduced, so it is inhibited gene or operon by one (mandatory or optional) essential Gene. These growth analyzes can be carried out automatically, so that a very large number of genes can be examined within a short period of time can be. The plasmid is isolated from these clones and the DNA Sequence of the cloned genome fragment that serves as a template for the asRNA  Synthesis serves, determines and consequently the structure of the essential gene determined.

A plasmid vector suitable for the CAI method is shown in Fig. 1. It contains a genomic or subgenomic DNA fragment from the microorganism to be examined under the control of an inducible promoter (P _i ) and other conventional expression signals and an mRNA-stabilizing element, so that the DNA fragment is expressed in the form of antisense RNA (asRNA) can become and has a long biological activity. A suitable promoter is e.g. B. the Tet promoter. In a particularly preferred embodiment, the CAI vector additionally encodes a gene for a regulatory protein which regulates the promoter, in this case, e.g. B. the Tet repressor, which by an exogenous or extracellular signal, such as. B. tetracycline can be controlled. The CAI vector of the special embodiment of Fig. 1 further contains one or more selectable marker genes and two origins of replication (ori), one for the microorganism to be examined (referred to here as a pathogen) and another for a conventional cloning host, e.g. BEcoli. With the help of such CAI vectors, antisense libraries can be created from entire microbial genomes.

Fig. 2 shows a schematic representation of a preferred CAI method. AsRNA is synthesized from a CAI plasmid, which contains small fragments of a genomic library of the microorganism to be investigated, from an inducible promoter (P _i ) under the control of an extracellular signal (see FIG. 1). The asRNA hybridizes in a sequence-specific manner to the mRNA of the gene which corresponds to the cloned DNA fragment on the CAI plasmid. The translation of this mRNA is reduced or prevented by the formation of the asRNA-mRNA hybrid. The result is a deficient microorganism that is unable to produce the gene product in question. If it is the product of an essential gene whose formation is inhibited (A), the viability of the corresponding clone is restricted or prevented. The viability of the microorganism is determined below on the basis of its life or survival or reproduction rate in a defined biological system. If there is no induction of asRNA synthesis (B), or if the CAI plasmid contains the fragment of a non-essential gene (C), the clone of the microorganism is normally viable and able to reproduce.

In particularly preferred embodiments of the CAI method, entire antisense RNA plasmid banks are analyzed from genomic fragments of the microorganism to be examined (see FIG. 3). A genomic library with CAI plasmids (see Fig. 1) is transferred into the homologous microorganism to be examined under non-inducing conditions and the plasmid-bearing clones are selected using a plasmid-coded marker. The viability of the individual clones, each of which receives a specific CAI plasmid from the gene bank, is then examined in direct comparison on the basis of its propagation rate under induced or non-induced conditions (+ and - in the figure), based on the asRNA synthesis. In clones that reproduce little or only slowly under asRNA-inducing conditions, the translation of at least one essential gene is prevented. The CAI plasmids are isolated from these clones. The essential genes are identified by sequencing the genomic fragments in the isolated CAI plasmids.

This approach can also preferably be combined with a subtractive method (SCAI), an embodiment of which is illustrated in FIG. 4 for illustration. A genomic bank with CAI plasmids (see FIGS. 1 and 3) is transferred into the homologous microorganism to be examined and the resulting individual clones are pooled as a bacterial CAI bank. This pool is split into two identical groups (the driver and the tester pool) for selection.

The expression "driver" is used for that pool of bacterial Cloning used, which is treated so that the inducible promoter is activated and asRNA expressed by the CAI vector. The "Tester" pool contains an identical set of clones with CAI plasmids, but below non-inducing conditions is maintained and thus wild-type Possesses properties.

As a rule, the "Driver" pool is used for selection (eg in the animal), while the "Tester" pool is kept untreated. However, both groups can also be subjected to a selection, with only the “driver” pool being induced by the signal (for example tetracycline) being administered. Clones in which the translation of an essential gene is inhibited by the expression of a specific asRNA are lost during the selection from the group. After an appropriate time, the surviving clones of both groups are recovered and the CAI plasmids isolated from the clones of both groups. The cloned genomic fragments are then amplified by PCR, using oligonucleotide primers which hybridize with vector sequences to the side of the cloned genomic fragments. Those amplified DNA fragments that are parts of essential genes are enriched and isolated by subtractive hybridization (see Fig. 8).

A promoter suitable according to the invention for a CAI vector is for example the Tet promoter, whose activity is via a regulatory Proten (in this case the Tet repressor) can be controlled and by an extracellular signal (tetracycline) can be induced. Further inducible promoters are known in the art.

Antisense RNA stabilizing elements are known to those skilled in the art Known area and need not be explained here.  

The high efficiency of the CAI process when inactivating Individual genes in an organism result from the overlapping Cloning of small genomic fragments and the associated ones Synthesis of different asRNA descendants for a specific one Gene area. This way the likelihood of getting an asRNA becomes too obtained which efficiently inhibits the translation of the target gene sought, greatly increased. Such studies can be carried out on the entire genome of a pathogen, which is checking a very large number of individual genomic fragments. Here apparatus aids (robots) are advantageous to a high To achieve sample throughput. However, in these cases only certain conditions are examined, e.g. B. the growth of cells in a certain medium.

Through the additional use of subtractive procedural steps (subtractive Conditional Antisense Inhibition, SCAI), can increase the number of investigating individual clones are preferably greatly reduced.

Subtractive recombination mutagenesis (SRM) is preferred for Identification of facultative essential genes. The difference permanent gene mutations are generated to the CAI method, whereby the Enrichment of essential genes achieved via a subtractive step becomes. Like the CAI method, the SRM method can be used with gene banks from pathogenic microorganisms are carried out.

The SRM process is based on the inactivation of individual genes in the genome of a pathogen by fully inserting a particular one Suicide plasmids, this being part of a gene bank. The insertion of the Plasmids into the genome are made by homologous recombination. The successful insertion is by expression of a plasmid-encoded Antibiotic resistance markers appear.  

A preferred embodiment of the SRM method is illustrated with the aid of FIGS. 5 to 8.

FIG. 5 shows a suitable SRM vector which, like the CAI vector, contains a genomic or subgenomic DNA fragment of the microorganism to be examined, and an origin of replication (ori) for a cloning host (e.g. BEcoli), one or more selectable ones Marker genes and another conditionally active origin of replication for the microorganism to be examined, e.g. B. a temperature-sensitive origin or an origin, the activity of which depends on a replication factor present in trans and which can additionally be introduced into the system. Because the SRM plasmid contains a genomic sequence of the microorganism to be examined, when this vector is transfected in this microorganism, there is a homologous recombination in which the entire SRM plasmid is inserted into the genomic gene of the microorganism and the corresponding gene falls it is deactivated. This leads to an insertion mutant. Suitable inducible origins of replication are, as mentioned, temperature-sensitive oris or those that can be controlled by a factor, such as. B. the RGK factor pir or the pWV factor repA, which is supplied to the system in trans.

An SRM plasmid (see FIG. 5) is inserted into the genome of the microorganism to be investigated via homologous recombination between the genomic fragment of the microorganism cloned in the plasmid and the complementary genomic DNA sequence. After the plasmid has been transferred into the corresponding microorganism, those clones in which the SRM plasmid is inserted into the genome are isolated under non-permissive conditions, ie with inactive ori, by selection for the plasmid-coded marker. The SRM plasmid is also excised via homologous recombination. Under permissive conditions, the replication of the inserted plasmid is initiated, which results in sufficient amounts of free plasmid in the cells so that the plasmid can be isolated again from the clone. If an SRM plasmid has been inserted into an essential gene, the viability of the clone in question is restricted (A), while mutants in non-essential genes are normally viable (B).

As with the CAI method, a bank of insertion plasmids can be transferred from genomic fragments of the microorganism to be examined into this microorganism and genomic insertion mutants can be formed. This preferred embodiment of the SRM method is shown in Fig. 7. A bank of SRM plasmids, which contain individual genomic or subgenomic fragments, is transferred into the homologous microorganism to be examined. Under conditions that do not allow plasmid replication, genomic insertion mutants are selected with the aid of a plasmid-coded marker (see FIG. 5). Only insertion mutants that are mutated in a non- or optional essential gene can survive in this step, since mutants of an essential gene are not viable. The individual insertion mutants are combined in a pool and this pool is then divided into two identical groups, the driver and the tester pool. The driver pool is selected, e.g. B. by infection of an animal. The tester pool remains untreated. Through the selection, those clones are lost from the driver pool which contain an insertion in an optionally essential gene (which is necessary for survival and reproduction under the selection conditions). Subsequently, from the surviving clones of both pools, the plasmids inserted into the genome of the microorganism are recircularized and recovered under permissive conditions. The driver pool lacks plasmids which contain fragments of facultatively essential genes. The fragments cloned in the SRM plasmids are then amplified in both pools by PCR (see FIG. 4). Those amplified DNA fragments, which are parts of optional essential genes, are enriched and isolated by genetic subtraction (see Fig. 8).

A special embodiment, which makes use of subtractive hybridization for the enrichment in fragments of essential genes, is exemplified in Fig. 8.

• A: PCR-based genetic subtraction. The tester DNA fragments (see FIGS. 4 and 7) are ligated with an adapter oligonucleotide in such a way that the adapter is only covalently linked to one of the two DNA strands of a double-stranded tester DNA fragment. B. is achieved by the ligation of a double-stranded, non-phosphorylated adapter to the 3'-phosphorylated DNA fragments of the tester DNA. These tester DNA fragments are then mixed with a molar excess of driver DNA fragments. The mixture is denatured and slowly rehybridized. Overhanging single-strand ends are then filled up with DNA polymerase to form the double-strand. The products of this reaction are amplified by PCR, using oligonucleotide primers which correspond to the adapter sequences. Only those tester DNA fragments that have not hybridized with driver DNA fragments are amplified exponentially amplified and then isolated by cloning.
• B: Genetic subtraction by physical separation from biotinylated DNA fragments. The driver DNA fragments will be biotinylated and then in excess with tester DNA Fragments mixed, denatured and slowly rehybridized. The biotinylated homo-driver-driver double strands and heteroduplexes (Driver testers double strands) are made by extraction with carrier  coupled streptavidin from the tester-tester homoduplexes severed. The latter are isolated by cloning.

The insertion mutants generated, for example, by SRM are shown in Animal experiments or cell culture systems with regard to their changed biological properties examined. Through the targeted use special host cells, e.g. B. cultured macrophages or host tissues, e.g. B. Spleen, gene groups can be selected, the essential properties determine the pathogen, e.g. B. the colonization of certain host cells. If the surviving mutants are isolated from the cells, they are missing Mutants of essential genes. If you subtract from the complete gene bank, the surviving mutants, you get the mutants of the essential Genes. This is done using a special PCR-based Subtraction step.

The CAI or the SRM procedure is a very efficient method for one clearly identify and characterize essential genes. Eat there tial genes represent a natural target for inhibitory agents the procedures presented form an ideal basis for the development of new ones Active ingredients.

The genes identified are identified in the methods described below used directly for drug screening, compared to conventional process, elaborate purification steps can be dispensed with can. The focus of these processes is on bacterial carrier cells that for screening for prophylactic and therapeutic agents can be used.

The gene deficient microorganisms produced are then on their Tested for viability or viability. Suitable Test systems are e.g. B. In vitro systems, cell culture systems, tissue culture systems and animal models as a natural environment. If the procedure at  H.pylori applied, the organisms are on the one hand on a so-called. Full medium grown, the full medium making the best possible advance enables growth for H.pylori. At the same time, the deficient H.pylori organisms grown in a culture which is the natural environment of H.pylori should correspond as closely as possible. It cell cultures based on primary cultures or Cell lines from gastrointestinal tissue are used or differentiate decorated primary tissue (spheroids) in culture medium. More options to simulate the natural environment of H.pylori exist in .der Use of stimulated macrophages, because H.pylori has the Ability to not be absorbed and metabolized by them. It can also be checked whether the deficient H.pylori Organisms are capable of moving about in immunodeficient mice to establish certain period.

If a deficient H.pylori bacterium is able to reach full medium survive, but does not grow in a natural environment as above the gene deficient in this organism is described as optional essential gene.

If the deficient H.pylori organism in neither test life is viable, it is an absolutely essential Gene.

Generally, microorganism genes can be of one of these categories be assigned.

From these results, the mutated or / by asRNA suppressed sequences identified and one of these two Categories are assigned, or the category of non-essential Genes when the gene deficient organism has no impairments in shows its ability to grow.  

Another object of the present invention is to provide a genetic method for isolating and cloning the identified essential genes from various clinical Helicobacter isolates or from heterologous pathogenic germs of clinical importance. The method according to the invention therefore further comprises the steps

• a) Preparation of primers for the amplification and detection of homologous gene sequences in heterologous microorganisms
• b) Identifying the homologous gene sequences.

These further process steps are preferably carried out in it, so-called megaprimer of the identified essential To produce Helicobacter genes by means of PCR (polymerase chain reaction), their sequence directly from the corresponding plasmids of the mutagenized DNA sections can be derived. These primers can then be used to identify the essentials already identified Isolate genes from different Helicobacter isolates. If this essential genes have correspondences in other microorganisms, the primers may also be used to isolate these genes from Helicobacter different microorganisms can be used. Farther can then determine the exact DNA sequence of the isolated genes and the finding the gene variance within the different Helicobacter isolates or between the different microorganisms.

In the production of the megaprimer, DNA fragments with variable are created 3 'ends. Because of this property, it is possible to use the DNA fragments for the isolation of variable or related genes by means of the described Use PCR method.

Identify specific active ingredients

To identify new immunological agents from the pool of identified essential genes of a pathogen or for In this respect, further development of these active ingredients becomes very bacterial carriers  used effectively because the identified genes are directly in these carrier systems can be cloned and expressed there. The drug screening is then carried out directly with the aid of these recombinant, bacterial carriers. As Carriers are preferred attenuated bacteria, such as. B. Salmonella, used as this has a natural potential for immune stimulation feature. If these attenuated bacteria are used as carriers or Producers for the identified essential genes of the pathogenic germs used and with these vaccine strains an immunization on a If a mammal is carried out, a sustainable immune response can be triggered become.

Meanwhile, the immunological properties of this bacterial Carrier systems have been refined so far that a targeted immune response can be triggered (VanCott et al., 1998; Carrier patent EP 98116827. 1). This property is significant in that the different Pathogens often only over a certain branch of the Immune system can be effectively combated. That is, protective mediators Antigens can only be identified if they are the immune system presented in the correct form. Only if the carrier used has been loaded with an effective antigen, it can lead to a Protective effect come. Because of the diverse immunological Characteristics of bacterial carrier systems and their superiority compared to conventional synthetic adjuvants, these are for Identification of immunologically relevant antigens particularly suitable.

In addition, the bacterial carrier systems can be used with efficient Gene expression systems are equipped, which the production also allow problematic antigens (PCT / EP 91/02478, EP 98116827.1). Due to the direct subcloning of the isolated essential genes and the ease of use of the bacterial carrier in the manufacture and Vaccination can produce a large number of antigens in a relatively short period of time tested for their immunogenic and protective potential  become. In conventional methods, the test antigens have to be countered time-consuming purification processes are subjected to often already during the genetic engineering production of the selected Antigens occur in bacteria with toxic problems Effect of these antigens linked to the producing bacterial strain are.

There is an important prerequisite for the development of active ingredients in determining the immunogenic potential of the identified sequences to determine to what extent the corresponding gene products for the Production of antibodies or vaccines are suitable.

To identify immunological agents against clinically relevant Helicobacter organisms must first be determined to what extent that Gene product of the identified essential gene immunogenic properties owns. That is, it must be determined experimentally whether with the antigen triggered a humoral and cellular immune response in a mammal that is directed against the original gene product of the pathogen. Under no circumstances are such antigens excluded in the The immune system does not recognize a natural infection become. On the contrary, one might rather expect that e.g. B. at chronically infected people the immune response against protective mediators Antigens are suppressed or of a quality that ultimately is none Protective effect mediated. However, such antigens are excluded are subject to a high genetic variation and thus an effective one Immune responses are hardly accessible.

To prove the identity of the identified gene product in a naturally occurring infection, is antiserum from patients gained either with active gastritis with discomfort suffer from, or from patients in whom the Helicobacter infection is asymptomatic runs. These are used to separate the electrophoresis  recombinant protein tested in a classic Western blot procedure. Finds a recognition reaction with a recombinant protein both serums, that is, that of a patient with a brilliant and one Patients with asymptomatic Helicobacter infection, instead, plays this protein plays a role in a natural infection. Will that recombinant polypeptide, however, only from the patient's serum of a symptomless infection, this can also be an indication of be a protective potential of the corresponding protein. Farther Antibodies that are specifically directed against this protein can may be used for passive immunization.

Also of particular interest are antibodies from individuals who are demonstrably no Helicobacter carriers, as these are protective Let potential of a corresponding recombinant polypeptide close.

Furthermore, the immunogenic polypeptides are used together with suitable additives for immunization in vivo. Used various adjuvants, bacterial toxins, cytokines or a polypeptide according to the invention as a live vaccine. The immune response is then tested to determine whether it has been administered after a certain polypeptide of the invention in combination with corresponding ones Additive after infection with the homologous germ a protective Effects against other homologous infections (e.g. infections with different H.pylori strains).

Yet another way to test immunogenicity is to in the animal model (e.g. mouse, rabbit) an immune response against Helicobacter or other microorganisms trigger and from the immunized animals to obtain antibodies, which are then used in another Western blot analysis can be used. At the same time Patient biopsies in situ immunologically with the same antibodies  to be examined since Helicobacter and other microorganisms in culture lose or gain certain proteins.

At the same time, it is preferred to investigate whether an infection with heterologous germs (preferably other gram-negative bacteria), which express the corresponding polypeptide, achieved a protective effect can be.

After determining whether the identified genes or their Expression products are able to elicit an immune response, can be further examined according to the method of the invention whether also treated an existing infection with such antigens can be. Can a polypeptide that shows a therapeutic effect, it is preferred also on its Activity in infections with heterologous germs examined.

The screening for prophylactically or therapeutically effective, immunological substances can proceed according to the following scheme, although compliance with the individual steps is not mandatory:

• 1. Cloning the identified gene into an appropriate bacterial Carrier strain and proof as well as quantification of the complete Gene product by SDS-PAGE.
• 2. Immunological characterization of the gene product produced with Help from (a) sera from infected and / or naturally protected hosts, that should recognize the gene product in the carrier strain; (b) Hyperimmune sera from animals using the recombinant Carrier strain were immunized. Whereby the respective Hyperimmune serum the original gene product in the pathogenic germ should recognize. It may be possible that the original Antigen only in a certain development period from Pathogen is produced.  
• 3. The protective effect of the individual antigens in the prophylactic or / and therapeutic application is in Animal model examined.

All protective antigens identified using the procedures described can now be further developed in a second step. In the foreground of this further development is a. the evaluation of the genetic constancy of the protective antigens identified within the Pathogen or related pathogenic germs in its worldwide Distribution. It will continue to develop effective vaccines on which genetic differences in the immune system of the vaccine. aim Both methods are the identification of antigens or epitopes that can be applied as widely as possible. To capture the The gene variability within a species or homologous germs can so-called mega-primer approach can be used. From the plasmid with the relevant gene is directly gene-specific primers with variable 3'- Ends produced via PCR, which amplify homologous genes enable. Based on the determined DNA sequence of the amplified genes their variability can be derived and z. B. genetically constant areas determined become.

The genetic differences between individual vaccinates, on one To react to defined antigen can be done with the help of in vitro vaccination be evaluated. Different donors become this antigen presenting cells (APC) isolated, e.g. B. dentritic progenitor cells, which expands in vitro and is loaded with the antigens to be tested are, the antigens preferably via appropriate vectors be expressed. The identified genes can also be used individually or in defined combinations in dendritic cells (DC) of uninfected Donors are expressed. The gene products from the Processed host cell and presented by the MHC complex. Are DC especially for the antigen presentation versus naive or  suitable for "slumbering" T cells. DC become more autologous with T cells Incubated donor, it is possible to determine whether this donor is against the antigen used would react if it were natural it would come into contact, e.g. B. as part of a vaccination. Based on Immune response of the T cells can indicate a possible immunogenicity of the appropriate antigen. Such an immune response consists, for example, of a proliferation of the T cells or Cytokine release especially of IL-2 and IL-4. The cytokines can for example using a commercially available assay kit (e.g. from Genzyme Cambridge M.A.) are evaluated.

Finally, those identified in the manner described and characterized antigens or epitopes for the development of the first Vaccine prototypes are used. This is between two Vaccine types differed, active and passive vaccination.

For passive immunization, the vaccinated antibody or Antibody fragments with a protective or inhibitory effect from the outside fed.

Antibodies are in the form of polyclonal, preferably monoclonal Antibodies (MAKs) or recombinant antibodies are provided. For this include antibodies that are specific to the polypeptides of the invention or their subunits and fragments react and for a prophylactic and / or therapeutic application, e.g. B. passive immunization, can be used. These anti-protein or anti-peptide antisera or monoclonal antibodies using standard protocols e.g. B. by the immunization of animals such as mice, rats or goats with a purified polypeptide of the invention, a fusion protein or a subfragment of it. In addition, the Animals are also immunized with bacterial vaccine carriers that use corresponding genes of the invention and the encoded  Express polypeptides. The antibodies are preferred immunospecific against antigenic determinants or epitopes described Helicobacter polypeptides or a closely related Polypeptide that has at least 90% homology. she are not cross-reactive with polypeptides, e.g. B. a homology of have less than 80%.

Starting from a cell line that is a polypeptide specific monoclonal antibodies can be produced from the coding gene such an antibody, chimeric genes are created, the antibodies determine, consisting of an antigen binding domain from the Mouse and the Fc part of a human antibody. These antibodies can be produced in cell lines or transgenic animals.

Instead of antibodies that were generated in the animal, too Antibody fragments, mini-antibodies, are used which, for. B. in one heterologous system like bacteria are made. These mini antibodies can be either monovalent or bivalent and consist of dimerized single chain molecules (Kujau et al., 1998; Kalinke et al., 1996; Pack et al., 1993).

Antibodies to the immunogenic polypeptides of the invention can also generated in plants. Examples of this are e.g. B. from Hiatt and Ma (1993) by Engelen et al. (1994) and Ma et al. (1994). Depending on the plant used, these can e.g. B. directly to Consumption and thus used as an oral vaccine.

Another very widely applicable way of producing antibodies is in Milk and eggs from immunized animals. If you administer z. B. pregnant cows, Suitable antigens for sheep or horses can be found in milk Immunoglobulins that can be used to develop a vaccine. The Milk can then either be administered directly as a vaccine, or a  concentrated immunoglobulin extract. The same Antibodies (hyperimmune antibodies) can also be found in chicken eggs are produced (Ling et al., 1998; Sasse et al., 1998). The described Immunogenic polypeptides of the invention can therefore also be used for development of a milk product or chicken eggs used as oral Vaccine can be used.

According to the invention, the generated antibodies or their fragments tested for their applicability. You can do this by known methods be purified (precipitation, chromatographic processes) and at be examined, for example, to determine whether the infection process of H. can inhibit pylori (adhesion assays) or activate on complexes ment or ADCC ("antibody-dependent cell-mediated cytotoxicity", anti body-dependent cell-mediated cytotoxicity).

For passive immunization, the antibodies, which are made using the Polypeptides of the invention were generated, either orally or intra administered gastric. For this, the antibodies are treated with a bicarbonate Buffer mixed. But they can also be administered systemically, whereby they do not have to be buffered.

Antibodies are preferred alone or in combination with others non-immunological agents used, e.g. B. with antibiotics or Proton blockers.

Active vaccination relies on an immune response from the vaccinated Organism itself is triggered. Dosage forms of Vaccines as antigens, antigen fragments, subunit vaccine, as DNA Vaccine, as a live vaccine or as a food vaccine.

Antigens are those polypeptides or their fragments that are in vivo Can cause immune response.  

If a polypeptide is to be provided as a subunit vaccine, it will first in its subunits or structural domains according to its Antigenicity pattern decomposed (e.g. T and B cell epitopes). This Antigenicity patterns can be created using a computer program be immunogenic regions that consist of a short polypeptide sequence of about 8 to 10 amino acids, can be recognized (Hughes et al., 1992). The individual pieces of polypeptide can then then on their immunogenicity in the mouse or in primates or People to be tested. You can do this either as cleaned Polypeptides that have been synthesized in combination with corresponding additives such as an adjuvant, toxin or cytokine be administered, or as a fusion protein to a known immunogenic Protein or protein subunit such as B. the cholera toxin B subunit (Liljeqvist et al., 1997). Furthermore, the immunogenic Peptides in outer membrane proteins such. B. the OmpS Maltoporin from E.coli incorporated and expressed heterologously in a vaccine carrier strain become (Lang and Korhonen, 1997).

To develop a DNA vaccine, those in the invention characterized polynucleic acid molecules "naked" in fusion with a eukaryotic tissue-specific promoter or in the form of a plasmid be administered. The "naked" DNA or the corresponding plasmid is used in combination with an additive such as a reagent that cellular permeability changes such as B. bupivacaine (WO 94/16737), cationic lipids such as e.g. B. DOTMA (N- [1- (2,3-dioleyloxy) propyl] -N, N, N trimethylammonium chloride, DOTAP (1,2-bis (oleyloxy) -3-trimethyl ammonio) propane), DDAB (dimethyl-dioctadecyl-ammonium bromide), DOGS (dioctadecyl-amidolglycyl-spermidine) or cholesterol derivatives, silica, Gold or tungsten (Tang et al. 1992) or in liposomes (WO 93/18759, WO 93/19768, WO 94/25608, WO 95/2397) or microparticles, administered. Examples of useful promoters and gene ferries are from Hartikka et al. (1996). For application of the  However, polynucleotide molecules can also, for. B. attenuated salmonella be used. The bacteria are used for this with eukaryotic Expression vectors containing a polynucleotide molecule of the invention transformed and then administered orally. The plasmid DNA is then transferred from the bacterium to the host (Darji et al., 1997). For Transformation of attenuated carrier bacteria can also be filamentous Phages are used. The advantage of this is that it is a extremely high number of plasmids can transmit.

The development of a live vaccine includes, among others, viral ones such as e.g. B. adenoviral or chickenpox virus vectors, or bacterial vectors such as Salmonella, Shigella or Lactobacillus. Attendees, non-virulent Salmonella typhimurium strains used for recombinant Expression of heterologous antigens can be used and orally have been characterized many times (Mekalanos, 1994, WO 92/11361, Cirillo et al., 1995 and Dorner (1995). More bacterial Vectors that can be used as vaccine vectors are from Cirillo et al., (1995) and Dorner (1995). A polynucleotide Molecule of the invention, which is for a therapeutic or prophylactic effective polypeptide is encoded, either in the bacterial Genome stably integrated and subjected to a transport system that the Presentation on the bacterial surface enables (PCT / EP 94/04286; WO 97/35022). The corresponding polynucleotide molecule can be found in Bacteria also exist as a plasmid in the free state.

Vaccines are usually with suitable additives such. B. Adjuvants, bacterial toxins, cytokines, etc., which the immunogenic polypeptide in its protective or therapeutic effect support. Adjuvants with minor side effects for use in humans, for subunit vaccine and live vaccine, but in part also come into question for DNA vaccines, z. B. aluminum hydroxide, Aluminum phosphate, calcium phosphate, N-acetylmuramyl-L-threonyl-D-  isoglutamine, N-acetyl-normuramyl-L-alanyl-D-isoglutamine, N-acetyl muramyl-L-alanyl-D-isoglutamyl-L-alanine-2- (1'-2'-dipalmitoyl-sn-glycero-3- hydroxyphosphoryloxy) ethylamine, liposomes, monophosphoryl lipid A, Trehalose dimicoloate, fungal polysaccharides such as B. Schizophyllan, Muramyl- Dipeptide, Muramyl dipeptide derivatives, as well as phorbol esters, saponins and immunostimulating complexes (ISCOMS) (Gupta and Siber, 1995). As bacterial toxin can e.g. B. cholera toxin or its subunits or the heat-labile toxin from E. coli can be used. Although these highly potent as adjuvants, they may be active due to their toxicity can only be applied to humans to a limited extent. With the help of certain However, mutagenesis techniques can develop molecules that are active, but are non-toxic (O'Hagan, 1998).

Another way to prevent and / or prevent the immune response Optimizing therapeutically active substances of the invention is that corresponding polypeptide as a fusion protein with an immunogenic To express protein domain. One possibility is e.g. B. in the Pilin DSL domain from Pseudomonas aeruginosa as a fusion partner use. Also described are fusion proteins that bind to glutathione S-transferase or thioredoxin were fused (Hill et al., 1997; Gabelsberger et al., 1997). The corresponding fusion protein can in each case be produced and administered as a subunit or live vaccine.

The immune response of the identified immunologically active substances can also be modulated by combining it with certain cytokines. For simultaneous administration offers a co-expression of the polynucleotide sequences of the invention with a particular cytokine in Salmonella or another Host bacteria. The corresponding cytokine can either do this a separate plasmid, in series or as a fusion protein with the desired polynucleotide sequence of the invention and then encoded in the host bacteria are transformed. Possible cytokines are  such as B. Interleukin-6 (IL-6), Interleukin-10 (IL-10) or Interleukin-12 (IL-12) stimulate the immune system.

Individual immunogenic agents can be used for further optimization Substances of the invention with each other or in combination with known ones immunogenic substances such as B. VacA or its individual Subunits can be combined. The corresponding polypeptide can together with at least one other Helicobacter antigen, such as. B. the native urase or its subunits, fragments of homologues, Mutants or derivatives thereof are expressed. You can also e.g. B. different subunit vaccine individually or as a fusion protein described above can be administered together. For this you can again z. B. purified polypeptide molecules in combination with a suitable adjuvant, bacterial toxin or cytokine can be used. Furthermore, various combinations of nucleotide sequences can be used immunogenic subunits of the polypeptide molecules described a common plasmid prepared and administered as a live vaccine become. A vaccine vector of the invention can thus be one or more Contain polypeptides of the invention, derivatives or fragments of the like. There is also the possibility of combining a DNA vaccine with one or more cleaned subunit vaccines in a suitable one Carrier substance, as already described above.

To identify new pharmacological agents from the pool of identified essential genes of a pathogen or for Further development of these active ingredients can also be very bacterial carriers can be used effectively because the genes identified directly in this Carrier systems can be cloned and expressed there. The active ingredient Screening is then carried out directly with the help of these recombinant, bacterial Carrier.  

Display systems serve to express an expressed polypeptide of the invention to present the cell surface of bacteria. The transportation of Polypeptides through the inner membrane allow a signal peptide on Amino end, while other parts are storing and anchoring in the take over outer membrane. Various external carrier components are used Membrane proteins from E. coli have been described as e.g. B. PhoE (Agterberg et al., (1990) or OmpA (Francisco et al., 1992). However, it can also Fusions with the transport domain of the IgA protease precursor IgAβ can be used (Klauser et al., 1990). Examples of display systems are e.g. B. the DsbA system (PCT / EP 94/02486) or the car transporter system (AIDA; WO 97/35022). The polypeptides presented on the surface can then be used for binding studies with peptide or combinatorial chemical substance banks are used. The attachment studies can with the help of a "High Through Put" system, the high test rates allows to be carried out in liquid or bound form. For this, the presented polypeptides z. B. a chromatophore coupled, which in combination with another chromatophore, the the drug peptide or chemical substance is coupled, a Color reaction enables. The corresponding active ingredient component can however also z. B. marked with a fluorescent dye or to a solid Carrier matrix can be coupled. When using a "Solid Phase System" is previously either the polypeptide of the invention used or conversely, the peptide or combinatorial drug bank to the Carrier matrix coupled. The respective dye-labeled component binds then to the immobilized component, causing a color reaction again is made possible. After the binding reaction there must be several Washing operations are carried out before the appropriate substance is isolated. Advantage of the "Solid Phase System" compared to the binding in Liquid is that the active substance can be isolated faster because the unbound substances are washed away.  

Other methods for the identification of new pharmacological agents are based on the knowledge from the primary structure of the identified essential genes or use the purified genetically manufactured gene products.

An alternative embodiment of the method according to the invention consists of specific binding partners of the genes identified by the to find encoded polypeptides.

Homology studies with Helicobacter and others may be preferred Organisms are carried out, e.g. B. with the help of computer alignments, Southern blots, PCR and the like and subsequent assignment of the Sequences. Because of homologies it can then point to potential Binding partners of the proteins are closed.

Combinatorial binding studies can also be preferred Target-directed screening method using substances Libraries are carried out. The potential binding substances are presented bound in a special arrangement, e.g. B. in Microtiter plates or other carrier materials. Then that will "Target", as a rule purified, possibly recombinant Helicobacter proteins, added in soluble form, what the detection an interaction between the target and certain substances enables. Indirect detection can be provided by labeled antibodies that are directed against the substance, or by introducing additional Elements ("tags") are brought into the target.

Another variant of the binding studies is the expression of Helicobacter proteins in recombinant bacteria (e.g. those that do produce fluorescent protein GFP or certain enzymes) which the Present proteins on the surface, and then test one Substances library.  

Furthermore, the three-dimensional structure of the Genes identified according to the invention 43859 00070 552 001000280000000200012000285914374800040 0002019927740 00004 43740 encoded polypeptides or theirs Fragments can also be determined by crystallographic analysis. At Sufficient resolution can be any "bags" or other Binding points are exactly characterized in their three-dimensional structure. Based on this data, the structure of potential binding partners can be calculated become.

With processes such as "two-hybrid system", display systems, "High Throughput screening "or combinatorial binding studies can randomly generated polypeptides are identified that are attached to the Helicobacter Polypeptides of the invention or their fragments, or to others bind polypeptides identified according to the invention. Will this way If the corresponding peptide is found, it can be chemically modified until the optimal possible bond is reached. That identified Polypeptide can e.g. B. used as an inhibitor by z. B. to a Toxin and an internalization signal is coupled that the pathogenic Germ destroyed or as a peptide mimetic to bind the germ to prevent the cellular surface (EP-412,762 A and EP-B 31,080 A). With With the help of the "Two Hybrid Systems" activators of the Immune system are generated. The identified peptides that are attached to the Helicobacter polypeptides of the invention can do this to certain Ligands e.g. B. for the T cell receptor. So become one animals or humans infected by pathogens so equipped When peptides are administered, the body's immune system becomes specific attracted and activated.

Adherence to the individual steps is not mandatory here, but rather can be supplemented or replaced by further steps.

The respective prototypes of an immunological or pharmacological Active ingredient are subsequently developed and improved.  

The further development of a vaccine can be done by several antigenic gene products or parts thereof in one active substance can be combined and / or with different carriers or additives be administered. Different attenuated bacterial act as carriers or viral organisms and, as additives, adjuvants and / or cytokines.

For the further development of a pharmacological agent, an as effectively characterized lead structure chemically modified so that optimal binding and inhibition of the identified gene product he follows. Furthermore, the active ingredient should be well tolerated by the patient and have minor side effects.

A can be used to identify active substances that bind to polynucleotides Polynucleotide of the invention e.g. B. can be pre-coupled to a carrier matrix or vice versa, the active ingredients of the polypeptides or combinatorial Substance bank. The following scheme used is the same like the one already described for the polypeptides.

Such inhibitory substances can, but also polypeptides, peptides chemical substances, such as antibiotics. The inhibitory Effect can occur at different stages of replication combat microorganisms. examples are Expression inhibitors or enzyme inhibitors or other inhibitors, which the natural function of the Helicobacter and related microorganisms can affect. Such inhibitory Substances are also the subject of the invention.

Another way to find an optimal active ingredient against Helicobacter and Finding other bacterial infections is with the help of special ones Computer programs. Based on crystallographic data from the polypeptides described in the invention can be obtained a model will be created that is steric, electronic, hydrophobic and  so-called "resulting binding moments" (RBMs) with each other connects (Ray et al., 1998). On the basis of this model, further Substances are modeled on the computer that are already may contain identified lead structures, but with better ones Binding properties are equipped. However, it can also be completely novel active ingredients are designed.

Another aspect of the present invention is a nucleic acid which codes for an essential secretory gene from Helicobacter pylori which was identified by the method according to the invention described above. Essential Helicobacter genes were identified with the present method, whose nucleic acid sequences are shown in SEQ ID NO. 1 to 113 (odd numbers) are given. A nucleic acid according to the invention is characterized, for example, in that it

• a) one of those in SEQ ID NO: n, where n is an odd integer of 1 to 113 inclusive, nucleic acid sequences shown or a protein coding portion thereof,
• b) one of the sequences from (a) in the context of the degeneration of the genetic codes corresponding nucleotide sequence or
• c) one with one of the sequences from (a) and / or (b) under stringent Conditions hybridizing nucleotide sequence.

In addition to the invention shown in the sequence listing Nucleotide sequences and these sequences in the context of degeneration The nucleotide sequences corresponding to the genetic code include the The present invention also includes nucleotide sequences that match one of the above hybridize said sequences. The term "hybridization" according to The present invention is in Sambrook et al. (Molecular Cloning, A. Laboratory Manual, Cold Spring Harbor Laboratory Press (1989), 1.101-1.104) used. One speaks preferably of a stringent Hybridization if after washing for 1 hour with 1 × SSC and 0.1% SDS at 50 ° C, preferably at 55 ° C, particularly preferably at  62 ° C and most preferably at 68 ° C, especially for 1 h in 0.2 × SSC and 0.1% SDS at 55 ° C, preferably at 55 ° C, especially preferably a positive at 62 ° C and most preferably at 68 ° C Hybridization signal is observed. One of those Washing conditions with one or more of the invention Nucleotide sequences or one of these sequences in the context of Degeneration of the genetic code corresponding nucleotide sequence hybridizing nucleotide sequence is a nucleotide according to the invention quenz.

The nucleotide sequence according to the invention is preferably a DNA. she can also be an RNA or nucleic acid analogue, such as a peptide nucleic acid. Most preferably, the nucleic acid according to the invention a protein-coding section of the in Sequence listing nucleotide sequences shown or a sequence that a homology of more than 80%, preferably more than 90% and particularly preferably more than 95% of the nucleotides shown sequences or a preferably at least 20 nucleotides (nt) and particularly preferably has at least 50 nt section thereof.

The homology becomes in percent identical positions when comparing two Nucleic acids (or peptide chains) specified, with 100% homology means complete identity of the compared chain molecules (Herder: Lexicon of Biochemistry and Molecular Biology, Spektrum Akademischer Verlag 1995).

A nucleic acid according to the invention can be used for a secreted polypeptide Encode signal peptide or for a secreted polypeptide without signal peptide.

A nucleic acid according to the invention comprises both the sequence of the coding strand as well as the complementary sequence. Latter  can be used for example in the production of antisense nucleic acids Find application.

The invention also of course also relates to a gene bank which at least 2, preferably at least 20, more preferably at least 100 of the nucleic acids mentioned contains cloned in vectors.

A listing of those given herein and in the Sequence Listing nucleic acids according to the invention together with their gene products and their Functions and putative functions are given in Tables I and II.  

Table I

Mandatory essential genes

Table II

Optionally essential genes

Another aspect of the present invention is a vector that includes a contains nucleic acid according to the invention or a portion thereof. The Nucleic acid or the nucleic acid section can thus be cloned into the vector be expressed in either sense or antisense direction can. The nucleic acid section preferably has a minimum length of 15 Nucleotides, more preferably 20 nucleotides, more preferably 50 Nucleotides. This vector can be any prokaryotic or be a eukaryotic vector on which the DNA Sequence preferably located in connection with expression signals, such as e.g. B. promoter, operator, enhancer etc. Examples of prokaryotic Vectors are chromosomal vectors, such as bacteriophages (e.g. Bacteriophage λ) and extrachromosomal vectors such as plasmids, circular vectors are particularly preferred. Suitable prokaryotic vectors are e.g. B. Sambrook et al., Molecular Cloning (1987), Chapters 1-4. On the other hand, the invention Vector can also be a eukaryotic vector, e.g. B. a yeast vector or vector suitable for higher cells (e.g. a plasmid vector, viral vector, Plant vector). Such vectors are described, for example, by Sambrook et al. supra, chapter 16. CAI and SRM vectors as above described are also the subject of the invention.

Another object of the present invention is a cell with a vector according to the invention or one according to the invention Nucleic acid is transformed. In a preferred embodiment this cell is a prokaryotic cell, preferably a gram negative Bacteria, e.g. B. E. coli. On the other hand, however, the cell according to the invention can also be a eukaryotic cell, such as a fungal cell, a yeast cell, an animal or a plant cell. It is particularly preferred the cell is a microorganism, e.g. B. Helicobacter or Salmonella. Microorganisms transformed with CAI or SRM vectors have already been described above. These are, as with the above  Mutant banks that can be produced, also part of the Invention.

Another aspect of the invention relates to an essential and preferably secreted polypeptide from H. pylori. In particular, this is a polypeptide that

• a) one of the in SEQ ID NO: m, where m is an even integer from 2 to 114, amino acid sequences shown or
• b) one immunologically with one of the sequences according to (a) includes cross-reacting sequence.

Among immunological cross-reacting sequences are thus also Muteins, variants and fragments of those described in SEQ ID NO. 2 to 114 sequences shown includes. This includes sequences that by substitution, deletion and / or insertion of individual amino acids or short amino acid segments from the above sequences differentiate.

Based on homology analyzes using the FASTA protein program were able to identify the polypeptides whose sequence matched the Nucleic acid sequence could be found, certain features or a putative location in the bacterium can be assigned. Some of the possess polypeptides encoded by the nucleic acids according to the invention a signal peptide and are transported by the Sec-dependent mechanism is exported to its target site, while others do not have a signal peptide own and therefore probably via a Sec-independent Transport mechanism, e.g. B. secreted by the ABC transporter system (see Tables I and II).

Another object of the invention is a method for producing the polypeptides and fragments according to the invention. The production of Polypeptides according to the invention are preferably carried out by  a cell with a DNA molecule or vector according to the invention transformed, the transformed cell cultivated under conditions, at which an expression of the polypeptide takes place, and the polypeptide from the cell or / and isolated from the culture supernatant. It can polypeptide according to the invention both as a fusion polypeptide and as Non-fusion polypeptide can be obtained.

The polypeptide according to the invention can be used as an immunogen for the production of Antibodies are used.

The present invention thus also relates to an antibody against a polypeptide according to the invention is directed. Also subject of the Invention are fragments of such antibodies, such as. B. Fab fragments or FC fragments.

Yet another aspect of the invention is an inhibitor of polypeptides according to the invention, their fragments or their expression, Presentation or / and natural function. This is preferably a molecule which is capable of specific to a polypeptide or fragment thereof to bind or / and its expression, presentation or / and natural Influence function. The identification of such specific Binding partners have already been described above. Particularly suitable as Inhibitors are proteins or peptides that are a polypeptide according to the invention inhibit in its natural function, e.g. B. can by enzymes Blocking the active center can be inhibited.

Yet another aspect of the present invention relates to one pharmaceutical composition used as an active ingredient DNA molecule according to the invention, a vector according to the invention, a cell of the invention, a polypeptide of the invention, a Antibody according to the invention or fragment thereof and / or a inhibitory molecule that is capable of specific to a  to bind the polypeptide according to the invention, optionally together with ex Lichen pharmaceutical auxiliaries, diluents, additives and carriers contains.

A pharmaceutical composition according to the invention can be ver different ways and using individual components as effective substances to inhibit the reproduction of Helicobacter Organisms in a host, specifically used in humans.

The pharmaceutical composition according to the invention can on the one hand used to diagnose a Helicobacter infection. The Diagnostics at the nucleic acid level are preferably carried out using of hybridization probes or primers which have a specific DNA Have sequence that belong to at least a section of one of the SEQ ID NO. 1 to 113 (odd numbers) sequences are complementary, so that they allow amplification of the sequences according to the invention. We mentioned earlier, these amplification primers or probes can also for amplification and thus for the detection of related microorganisms are used if they have gene sequences that are for the same encode essential genes. Diagnostics are carried out at the protein level preferably with the help of the antibodies according to the invention.

Furthermore, the pharmaceutical composition for prophylaxis and Combat Helicobacter infections and related infections Suitable for microorganisms.

Another important aspect of the present invention is that Use of the identified essential genes of Helicobacter pylori for Prevention or control of Helicobacter or infection related microorganisms. In particular, they can be identified essential genes used for the production of vaccines (vaccines) be (see above).  

Another use of the polypeptides of the invention is in Purification of the antibodies against H.pylori polypeptides and against corresponding polypeptides from related and other microorganisms.

The invention is illustrated by the following examples, illustrations and the Sequence listing explained in more detail. In the sequence listing are the following Nucleic acid and amino acid sequences are shown.

Fig. 1 shows a schematic representation of a CAI vector.

Fig. 2 shows a schematic representation of a method of conditional antisense inhibition (CAI).

Fig. 3 shows a schematic representation of the investigation of the viability of deficient microorganisms based on their survival rates using the CIA method.

Fig. 4 shows a schematic representation of the subtractive CAI method (CAI).

Fig. 5 shows a schematic representation of an SRM vector.

Fig. 6 shows a schematic representation of the reversible inactivation of a gene by the insertion / excision of a conditionally replicating SRM plasmid.

Fig. 7 shows a schematic representation of an SRM process.

Fig. 8 shows a schematic representation of the enrichment of fragments of essential genes by subtractive hybridization.

Examples

The application of the overall procedure shown is exemplary on Example of the pathogen Helicobacter shown, but also lets other pathogenic germs.

1. Identification of essential genes of pathogenic microorganisms Step 1

Enrichment of H. pylori genes coding for secretory / excretory Polypeptides.

Production of an H.pylori gene bank in the minimal vector pMin2

The H.pylori wild-type strain 69A serves as the starting strain. The bacteria are grown on serum plates or another suitable medium (Westblom et al., 1991) at a temperature of 37 ° C. in an atmosphere of 5% O ₂ , 10% CO ₂ , 85% N ₂ . The chromosomal DNA is isolated according to the method of Leying et al., (1992), the DNA subsequently being purified using a cesium chloride gradient. 50 µg of the purified, chromosomal DNA is partially cleaved with the restriction endonucleases Sau3A and HpaII, the DNA fragments are separated in an agarose gel and the fragments in a size of 3 to 6 kbp are eluted from the gel using the Geneclean II kit (Bio101). The isolated DNA fragments are cloned into the BglII and ClaI cut pMin2 vector (Kahrs et al., 1995) and transformed via electroporation into the E.coli strain E181, to which the plasmid pTnMax9 was previously transferred. In total, approximately 4000 clones are generated using such an approach. The E.coli strain E181 is a derivative of the HB101 strain (Boyer and Roulland-Dussoix, 1969) and contains the lysogenic phage CH616 for replication of the pTnMax9 plasmid.

Serum plate formulation

36 g GC agar (base) in 910 ml aqua dest. suspend and autoclave

• - Let cool to approx. 45 ° C
• - Add 10 ml vitamin mix
• - Add 1 ml each of the antibiotic stock solution:
• - Vancomycin (10 mg /) in aqua bidest)
• - Nystatin (0.793 mg / l in DMF *)
• - Trimethoprim (5 mg / l in DMF *)
• - Amphotericin (5 mg / l in DMF *)
  * DMF = dimethylformamide
• - Add 90 ml of serum or
• - Add 8% horse blood = 80 ml
• - or an equal amount of human blood

Antibiotic stock solution

Vancomycin: 100 mg in 10 ml aqua bidist

Nystatin: 7.93 mg in 10 ml DMF (1 ml per liter GC agar clog)

Trimethoprim: 50 mg in 10 ml DMF

Amphotericin: 50 mg in 10 ml DMF
(Storage in the refrigerator for up to 8 weeks)

Vitamin mix (concentrate)

Dextrose (D-glucose): 100 g

L-glutamine: 10 g

Cysteine HCl (C ₃ H ₇ NO ₂ S x HCl x H ₂ O): 26 g

Cocarboxylase: 100 mg in 50 ml

Fe (NO ₃ ) ₃ : 20 mg aquabidest. to solve

Thiamine HCl: 3 mg

DPN NAD: 250 mg

Vitamin B ₁₂ : 10 mg

L-cysteine (C ₆ H ₁₂ N ₂ O ₄ S ₂ ): 1.1 g

Adenine: 1.0 g in 15 ml HCl

Guanine CI: Dissolve 30 mg (32%)

Uracil: 500 mg

L-arginine HCl: 150 mg

p-aminobenzoic acid: 13 mg
(filter sterile, fill in 10 ml portions and freeze)

Genetic enrichment of secretory / excretory H. pylori Gene products

The transposon TnMax9 located on pTnMax9 is equipped with the genetic marker β-lactamase. This marker is placed on the transposon in such a way that the selection of successful transposon insertions is made possible if it is in the correct reading frame of genes whose products are secreted or exported by E. coli strain E145 ^rif . The insertion of the transposon into such a gene leads to a gene fusion between the target gene and the marker, the fusion protein being discharged from the cell by a secretion and / or export signal determined in the target gene and the activity of the integral reporter gene being developed. In the case of β-lactamase, the clones can be detected directly by developing resistance to ampicillin. The TnMax9 transposon on pTnMax9 is activated via IPTG.

The gene bank transposon mutagenesis is carried out in pools of up to 20 individual clones. The respective pools are plated on LB plates which are mixed with 100 µM IPTG, 15 µg / ml chloramphenicol and 15 µg / ml tetracycline. In a second step, the TnMax9 mutagenized pMin2 plasmids are conjugated into the E.coll strain E145 ^rif because they are equipped with a corresponding mob signal (oriT). The pTnMax9 plasmids, however, are not transferred. E.coli E145 ^rif therefore results in a specific replication of the mutagenized pMin2 gene bank. The corresponding transconjugants are selected on LB medium with 15 ug / ml chloramphenicol, 15 ug / ml tetracycline and 100 ug / ml rifampicin. A total of 500 to 1000 transconjugants are combined in 2 ml of LB medium and grown in appropriate dilutions (10 ^-1 to 10 ^-2 ) on LB plates which are mixed with 50 µg / ml ampicillin. After culturing the plates for 36 hours at 37 ° C., 200 to 300 ampicillin-resistant clones with transposon-inserted plasmids are obtained in the entire batch.

step 2

Manufacture of gene-deficient H. pylori that are secretory / excretory Genes encoding polypeptides are mutated and the identification of such Genes with essential biological function.

Generation of gene-deficient H.pylori mutants

By coding the plasmids obtained with the TnMax9 mutated H. pylori genes for secreted / excreted polypeptides in a H.pylori wild-type strain gene-specific mutants can be generated. Due to the cloned H.pylori gene sequences on the plasmids occur in the case a double homologous recombination event to the genomic Insertion of the TnMax9 transposon into the chromosomal target gene and thus to inactivate it. Through the genetic marker on the transposon this process can be selected because the pMin2 plasmid in H.pylori is not replicated.

The H.pylori wild-type strain 69A is carried out in individual batches transformed with the individual plasmids obtained, the natural competence of the bacterium to absorb DNA is exploited. The bacteria are grown according to the standard cultivation conditions recorded in BHI medium and up to an optical density at 550 nm of 0.1 grown at 37 ° C under microaerophilic conditions. The Individual culture approaches are cleaned with 200 to 599 ng each Plasmid DNA was added and the culture continued overnight.  

Characterization of the biological function of the gene-deficient H.pylori Mutants in the growth test: The individual approaches are after the Cultivation plated on serum plates, which with 4 µg / ml Chloramphenicol are added. Regarding the growth characteristics of the individual mutants compared to the wild type strain can have 3 categories A distinction is made between: (1) mutants that do not grow; (2) mutants that form smaller colonies; (3) mutants that are normal colony size develop. These results can be seen for any starting plasmid reproducible. For a clear assessment of the biological The importance of the category 1 mutants that are deficient in genes becomes apparent CAI procedure supplied. The category 2 and 3 are analyzed in the other biological test systems.

step 3

Identifying the H. pylori genes coding for secretory / exported polypeptides.

To determine the primary structure of the identified H.pylori genes, the respective starting plasmids from the E. coli strain are used. The Plasmids are isolated from these strains and the nucleotide sequence of the Target genes by sequencing the areas above and below the Insertion point of the transposon in the target gene determined. The reading frame of the Target gene can be determined directly since the transposon-encoded β- Lactamase gene enters into an active fusion with the gene product of the target gene (see above). The sequencing is carried out using an ABI sequence automaton Manufacturer's details performed with the following sequence primers: M 13- F (GTAAAACGACGGCCAGT) and M13-RP1 (CAGGAAACAGCTATGACC).

To further characterize the genes, the Genebank des GCG program used, e.g. B. to identify known, homologous genes of other microorganisms (FASTA), for identification potential signal peptide regions (SPSCAN) or for the identification of Lipoproteins (MOTIFS).  

Part of the characterized clones could not be completely Gene sequence can be determined because the cloned DNA fragment is not that entire gene contained. The available DNA fragment is used to to get a DNA fragment with complete gene from the original gene bank isolate. These clones can then be used with a gene-specific Primer and a vector-specific primer the missing gene sequences amplified and then sequenced directly.  

literature

Goodwin, CS, Armstrong, JA, Chilvers, T., Peters, M., Collins, MD, Sly, L., McConnell, W., Harper, WES (1989) Transfer of Campylobacter pylori and Campylobacter mustelae to Helicobacter gen. Nov . as Helicobacter pylori comb. nov and Helicobacter mustelae comb. nov., respectively. Int J Syst Bact 39: 397-405.
Lee, A., Fox, J., Hazell, S. (1993) Pathogenicity of Helicobacter pylori: a perspective. Infect Immun 61: 1601-1610.
Malfertheiner P. (1994) Helicobacter pylori - From the basis to therapy. Bayerdörfer E, Birkholz S. Börsch G. et al., (Eds.) Stuttgart, New York: Georg Thieme Verlag; p. 1-104.
Marshall, BJ, Royce, H., Annear, DI, Goodwin, CS, Pearman, JW, Warren, JR, Armstrong, JA (1984) Original isolation of Campylobacter pyloridis from human gastric mucosa. Microbios Lett 25: 83-88.
Nomura, A., Stemmermann, GN, Chyou, PH, Kato, I., Perez-Perez, GI, Blaser, MJ (1991) Helicobacter pylori infection and gastric carcinoma among japanese americans in Hawaii. N Engl J Med 325: 1132-1136.
Parsonnet, J., Friedman, GD, Vandersteen, DP, Chang, Y., Vogelman, JH, Orentreich, N., Sibley, RK (1991) Helicobacter pylori infection and the risk of gastric carcinoma: N Engl J Med 325: 1227 -1131.
Pugsley, AP (1993) The complete general secretory pathway in gram-negative bacteria. Microbiol Rev 57: 50-108. Solnick, JV, Tompkins, LS (1993) Helicobacter pylori and gastroduodenal disease: pathogenesis and host-parasite interaction. Infect Ag Dis 1: 294-309.
Tadayyon, M., Broome-Smith, JK (1992) TnblaM - a transposon for directly tagging bacterial genes encoding cell envelope and secreted proteins. Gene 111: 21-26.
Warren, JR, Marshall, B. (1983) Unidentified curved bacilli on gastric epithelium in active chronic gastritis. Lancet i: 1273-1275.

Sequence listing

Claims (57)

1. A method for providing means for the detection, prevention and / or therapy of microbial infections, characterized in that it comprises the steps:

• A) Identifying essential genes and the corresponding polypeptides by producing gene-deficient microorganisms by conditional antisense inhibition (CAI) or / and subtractive recombination mutagenesis (SRM) and determining the viability or / and survivability of the gene-deficient microorganisms in a test system.
• B) Identification of specific active substances which are directed against the essential polypeptides and which inactivate the microorganisms or the microorganisms used.
• C) testing the identified active substances for their applicability as components of diagnostic, preventive and / or therapeutic agents,
• D) Formulating the applicable active ingredients as diagnostic, preventive and / or therapeutic agents.

2. The method according to claim 1, characterized, that obligatory essential genes are identified by CAI. 3. The method according to claim 1, characterized, that optionally essential genes are identified by SRM.   4. The method according to any one of the preceding claims, characterized, that a selection for genes is carried out before step (A) which for Encode polypeptides with a certain functionality or / and the encode polypeptides that are in a particular stage of development be expressed. 5. The method according to any one of the preceding claims, characterized, that the selection is carried out using hybridization methods is selected from subtraction and array methods. 6. The method according to claim 5, characterized, that the selection for specific subtracted apathogenic or pathogenic genes is carried out. 7. The method according to claim 5, characterized, that the selection for specific subtracted genes from H.pylori or H.heilmannii is carried out. 8. The method according to any one of claims 4 to 7, characterized, that selects coding gene sequences for exported polypeptides become. 9. The method according to any one of claims 4 to 8, characterized, that selects gene sequences coding for secreted polypeptides become.   10. The method according to any one of claims 4 to 9, characterized, that genes coding for polypeptides are selected which are used for Development of the vital form from the persistence form necessary are. 11. The method according to any one of claims 4 to 9, characterized, that genes coding for polypeptides are selected which are used for Development of the survival form from the vital form necessary are. 12. The method according to any one of the preceding claims, characterized, that in step (A) to determine the life and Survivability of the gene-deficient microorganisms Test systems selected from in vitro systems, cell culture systems, Tissue culture systems and animal models as a natural environment be used. 13. The method according to claim 12, characterized, that those deficient gene sequences that don't cultivable and not survivable in a natural environment gene-deficient microorganisms, the category of obligatory essential genes are assigned. 14. The method according to claim 12, characterized, that those deficient gene sequences that become cultivable but deficient in natural environment not viable  Microorganisms lead to the category of optional essential Genes can be assigned. 15. The method according to any one of the preceding claims, characterized, that the identified genes are used to prepare primers with the help of which appropriate genes from relatives Microorganisms, subspecies and / or species can be identified. 16. The method according to any one of the preceding claims, characterized, that specific active ingredients are identified in step (B), which the expression, presentation and / or function of the essential Affect polypeptides, especially immunologically active ones Substances, binding partners of the polypeptides or their fragments or / and inhibitory substances. 17. The method according to any one of the preceding claims, characterized, that step (B) a determination of the immunogenic potential of the Polypeptides or / and their fragments, wherein the identified genes are expressed and then a Western blot analysis is carried out and / or that with the identified polypeptides or fragments thereof vaccination performed in cell culture or in animal models and triggering a specific immune response is observed. 18. The method according to any one of the preceding claims, characterized, that step (B) a determination of the binding potential of the Polypeptides or their fragments by screening  Substance libraries, surface display processes, crystalline includes graphic analysis and / or computer modeling. 19. The method according to any one of the preceding claims, characterized, that the diagnostic, preventive or / and therapeutic agent in the form of passive vaccines or active vaccines to be provided. 20. The method according to claim 19, characterized, that the passive vaccines in the form of antibodies or / and Antibody fragments and the active vaccines in the form of heterologous carrier systems and / or in the form of antigens, Antigen fragments, subunit vaccines, live vaccines, DNA Vaccines or / and food vaccines are provided. 21. The method according to any one of the preceding claims 1 to 19, characterized, that the diagnostic, preventive or / and therapeutic agent include inhibitory substances, especially expression inhibitors gates or / and enzyme inhibitors. 22. A method for identifying essential microbial genes, characterized in that it comprises the steps:

• a) production of gene-deficient microorganisms,
• b) determining the viability and / or survivability of the gene-deficient microorganisms from (i),
• c) Identifying a protein coding section of a microbial DNA sequence in which the gene-deficient microorganisms are deficient.
• d) Characterize those DNA segments that are essential for survivability.

23. The method according to claim 22, characterized, that the gene deficient microorganisms are produced by a section of DNA is mutagenized in a microbial genome. 24. The method according to claim 22, characterized, that the DNA section mutagenized by transposon mutagenesis becomes. 25. The method according to claim 23, characterized, that the mutagenization of the DNA section on the microbial Genome is done by homologous recombination. 26. The method according to claim 25, characterized, that the SRM method is used. 27. The method according to claim 23, characterized, that the gene deficient microorganisms are produced by in microorganisms, a DNA section or a partial sequence thereof is expressed in the form of antisense RNA. 28. The method according to claim 27, characterized, that the CAI method is used.   29. The method according to any one of claims 22 to 28, characterized, that to determine the viability and / or survivability of the gene-deficient microorganisms test systems selected from vitro systems, cell culture systems, tissue culture systems and Animal models can be used as a natural environment. 30. The method according to claim 29, characterized, that those deficient gene sequences that don't cultivable and not survivable in a natural environment gene-deficient microorganisms, the category of obligatory essential genes are assigned. 31. The method according to claim 29, characterized, that those deficient gene sequences that become cultivable but deficient in natural environment not viable Microorganisms lead to the category of optional essential Genes can be assigned. 32. The method according to any one of claims 22 to 31, characterized, that identifying the protein coding DNA segment by Expression in a host organism and detection of the An expression product is present. 33. The method according to any one of claims 32 to 32, characterized in that it further comprises:

• a) Preparation of primers for the amplification and detection of homologous gene sequences in heterologous microorganisms
• b) Identifying the homologous gene sequences.

34. Nucleic acid coding for an essential secretory gene Helicobacter, identified by the method according to one of the Claims 22 to 33. 35. Nucleic acid according to claim 34, characterized, that it encodes a secreted polypeptide with signal peptide. 36. nucleic acid according to claim 34, characterized, that it encodes a secreted polypeptide with no signal peptide. 37. Nucleic acid, characterized in that it

• a) one of the nucleic acid sequences shown in SEQ ID NO: n, where n represents an odd integer from 1 to 113 inclusive, or a protein-coding section thereof,
• b) a nucleotide sequence corresponding to one of the sequences from (a) in the context of the degeneration of the genetic code or
• c) comprises a nucleotide sequence hybridizing with one of the sequences from (a) and / or (b) under stringent conditions.

38. Genbank, comprising at least two nucleic acids according to one of the Claims 34 to 37.   39. vector, characterized, that it contains at least one nucleic acid according to one of claims 34 to 37 or a portion thereof. 40. The vector according to claim 39, characterized, that it is a CAI vector. 41. The vector according to claim 39, characterized, that it is an SRM vector. 42nd cell, characterized, that they are with a nucleic acid according to any one of claims 34 to 37 or transformed a vector according to any one of claims 39 to 41 is. 43. mutant bank, characterized, that it consists of at least two microorganisms with one A vector according to claim 40 or a vector according to claim 41 are transformed. 44. polypeptide, characterized, that it is from a nucleic acid according to any one of claims 34 to 37 is encoded.   45. Polypeptide according to claim 44, characterized in that it

• a) one of the amino acid sequences shown in SEQ ID NO: m, where m represents an even integer from 2 to 114 inclusive, or
• b) comprises a sequence which is immunologically cross-reactive with one of the sequences according to (a).

46. polypeptide according to claim 45, characterized, that it is an essential secreted polypeptide. 47. polypeptide fragment, characterized, that there is an immunogenic portion of one of the sequences Claim 45. 48. Inhibitory molecule obtainable by the method according to Claim 1 characterized, that it is able to specifically target a polypeptide or fragment bind according to one of claims 44 to 47 or / and its expression, presentation and / or natural function influence. 49. Process for the preparation of a polypeptide or polypeptide fragment according to one of claims 44 to 47, characterized, that a cell with a nucleic acid according to any one of the claims 34 to 37 or a vector according to claim 39, which transformed cell cultured under conditions where a  Expression of the polypeptide takes place and the polypeptide from the Cell or / and the culture supernatant isolated. 50. Use of a polypeptide or a fragment thereof one of claims 44 to 47 thereof as an immunogen for production of antibodies. 51. antibody or fragment thereof, characterized, that it is specific for a polypeptide or a fragment thereof any of claims 44 to 47. 52. Pharmaceutical composition, characterized in that it is an active ingredient

• a) a nucleic acid according to any one of claims 34 to 37,
• b) a vector according to claim 39,
• c) a cell according to claim 42,
• d) a polypeptide or a fragment thereof according to any one of claims 44 to 47,
• e) an antibody or fragment thereof according to claim 51 and / or
• f) an inhibitory molecule according to claim 48,

optionally together with customary pharmaceutical auxiliaries, diluents, additives and carriers. 53. Use of a pharmaceutical composition according to Claim 52 for the diagnosis, prevention and / or therapy of a Helicobacter infection. 54. Use of a pharmaceutical composition according to Claim 52 for inhibiting the reproduction of Helicobacter  Organisms and / or other anthrogenic microorganisms in a host. 55. Use according to claim 54, characterized, that a nucleic acid according to any one of claims 34 to 37 as DNA Vaccine is formulated. 56. Use according to claim 54, characterized, that a polypeptide or polypeptide fragment according to one of the Claims 44 to 47 as a subunit vaccine or as a live vaccine is formulated. 57. Use of a pharmaceutical composition according to Claim 52 for the production of an agent for diagnostics, Prevention and / or therapy of a Helicobacter infection.