WO1996004381A1 - S. aureus fibronectin binding protein polypeptides and uses thereof - Google Patents

Abstract

An isolated D3D4 polypeptide from a Staphylococcus aureus Fbp, processes for its preparation and its use in the prevention of adhesion of bacteria, in particular gram positive bacteria, to extracellular matrix proteins on in-dwelling devices or to extracellular matrix proteins in wounds and also oral pathogens, to extracellular matrix proteins on surfaces in the oral cavity, in particular tooth surfaces.

Description

S. AUREUS FIBRONECTIN BINDING PROTEIN POLYPEPTIDES AND USES THEREOF

The present invention relates to novel polypeptides and monoclonal antibodies thereto, their preparation and their use to combat infection at the site of wounds, surgical implants and other in-dwelling devices such as catheters. The present invention also relates to the use of such novel polypeptides and monoclonal antibodies as antiadherent agents in oral hygiene. The present invention further relates to isolated nucleic acids encoding the polypeptide and to recombinant host cells transformed with DNA encoding the polypeptide.

One of the major complications associated with the clinical use of implanted materials and in-dwelling devices is bacterial infection. In particular, staphylococci have frequently been implicated in medical device-related infections (Dankert et al 1986. CRC Rev Biocompatability 2, 219-301). Once established the infection is virtually impossible to treat resulting in implant failure.

It has been suggested that the adhesion of a microorganism to a surface is an initial step in the development of such infections (Quie and Belani, 1987, J. Infec. Dis. 156: 543-547 ) and there is now evidence to suggest that a specific adhesion mechanism is involved in the pathogenesis of foreign body infections (Vaudaux et al. 1990, J. Biomat. Appl. 5: 134-153 ). Soon after coming into contact with blood, inert materials, such as used for intravenous cannulae and prosthetic implants, are almost immediately coated with a layer of extracellular matrix proteins, (Cottanaro et al 1981, Transactions of the American Society for Artificial Internal Organs 27:

391-395 ). In particular this layer includes the plasma protein fibronectin and it is believed that staphylococci are able to bind to fibronectin through bacterial cell surface receptor proteins known as fibronectin binding protein (Fbp). However , some studies have suggested that blood proteins do not promote adherence of staphylococci to biomaterial (eg. Muller et al 1991, Infect.Immun. 59: 3323-3326) thereby discouraging research into the interaction of these bacteria with these proteins as an approach in the prevention of adhesion to biomaterials.

Fibronectin binding proteins have been isolated from Staphylococcus aureus and the nucleoride sequence subsequently established [ Signas, C. et al. (1989) Proc. Nat. Acad. Sci 86, 699-703 : Jonsson. K. et al. (1991) Eur. J. Biochem. 202, 1041 - 10481 (Fbp A and FbpB respectively). The primary fibronectin binding domain of Fbp has been identified as a homologous unit (usually of 38 amino acids) that is repeated three times (D1-D3 region) and partially repeated a fourth time (D4 region). It has been reported that the affinity of the D domains for fibronectin is in the order D3 > D2 > D1 and that it is the C-terminal half of the individual domains that are primarily responsible for the binding (Huff S. et al. (1994) J. Biol. Chem. 269 15563- 70.

Previous attempts to combat staphylococcal adhesion to implants have involved modification of the surface of the prosthetic material to discourage adhesion of proteins ; e.g. coating with a "non-stick" material such as PTFE, or bonding antibiotics to the surface (Kamal et al, 1991, J. Amer. Med. Assoc. 265, 2364-2368 ).

There have also been proposals to use non-steroidal anti-inflammatory drugs to prevent adhesion of staphylococci to medical polymers (Farber and Wolff 1992, J. Infect. Dis. 166: 861-865).

EPO 163623, EP0294349, EP0397633 and WO92/02555 disclose certain fibronectin binding polypeptides from S. aureus.

Fibronectin binding protein of Staphylococcus aureus is known to exist in at least two variants FbpA and FbpB [Jonsson et αl.(1991 ), op. cit.].

A new fibronectin binding protein from S. aureus J2385 (see Methods (xii) in particular) has now been identified (WO94/18327, incorporated herein by reference).

Staphylococcus aureus J2385 has been deposited at the National Collection of Industrial and Marine Bacteria Ltd. (NCIMB), Aberdeen, Scotland under number NCIMB 40532 on 18 th December 1992.

The D1-D4 region has the amino acid sequence set out in Table 2 below.

The DNA encoding this region is shown in Table 1 below, along with the

DNA encoding the D1-D4 region of FbpA.

In the field of oral healthcare, pathogenic organisms (bacteria and fungi) in the oral cavity, in particular Streptococcus mutans, Lactobacillus species,

Antinobacillus actinomycetem comitans, Actinomyces viscosus, Fusobacterium nucleatum, Porphyromonas intermedia. Eikenella corrodens, Wolinella recta, Bacteroides forsythus, Porphyromonas gingivalis and Candida albicans are responsible for a variety of problems. Oral bacteria adhere to various surfaces in the oral cavity, such as teeth, gingiva and soft mucosal tissues, and form plaque on tooth surfaces. The latter can lead to the development of carious lesions, gingivitis, calculus and periodontal disease. Oral fungi can also give rise to infections in the oral cavity, for instance thrush. Previously, it has been suggested that a suitable

therapeutic approach is provided by the use of an anti-microbial agent, such as chlorhexidine, cetyl pyridinium chloride or triclosan which have a bacteriocidal or bacteriostatic effect.

More recently, it has been suggested that an alternative approach may be to use an antiadherent agent, to stop pathogenic organisms from adhering to surfaces within the oral cavity. Teeth become coated with an acquired pellicle which comprises an extracellular protein matrix. This includes specific and non-specific binding sites which are recognised by bacteria and fungi, in particular by receptors located on the surface of the bacterial and fungal cells. If these binding sites are blocked, then cells will be unable to adhere to the extracellular matrix. Thus, for instance, WO 84/04546 (NRDC) discloses the use of a combination of polymers for preventing the adherence of cariogenic bacteria to tooth surfaces whilst EP0182523-A (Imperial Chemical Industries pic) describes certain novel polymers comprising hydrocarbyl groups with pendant carboxyl and pendant polyalkylene oxide groups which are said to prevent the adherence of cariogenic bacteria on teeth. WO

93/16680 (SmithKline Beecham pic) describes the use of polyvinyl pyrrolidone as a bacterial anti-adherence agent.

In one broad aspect the invention provides an isolated D3D4 polypeptide from a Staphylococcus aureus Fbp and its use in the prevention of adhesion of bacteria, in particular gram positive bacteria, to extracellular matrix proteins on in-dwelling devices or to extracellular matrix proteins in wounds and of oral pathogens to extracellular matrix proteins on surfaces in the oral cavity, in particular tooth surfaces. The invention further relates to the manufacture of a medicament for such uses.

In particular the gram positive bacteria include staphylococci such as S.

aureus and coagulase-negative staphylococci, such as S. epidermidis.

The term 'oral pathogen' as used herein refers to bacteria and fungi which have been implicated in causing various disease states in the oral cavity, such as caries, gingivitis, periodontitis, calculus and thrush, for instance. Streptococcus mutans,Lactobacillus species, Actinobacillus actinomycetem comitans, Actinomyces viscosus, Fusobacterium nucleatum, Porphyromonas intermedia, Eikenella corrodens, Wolinella recta, Bacteroides forsythus, Porphyromonas gingivalis and Candida albicans. Examples of non-pathogenic early colonisers include Streptococcus sanguis and Streptococcus gordonii.

In-dwelling devices include surgical implants, prosthetic devices and catheters, i.e., devices that are introduced to the body of a patient and remain in position for an extended time. Such devices include, for example, artificial joints, heart valves, pacemakers, vascular grafts, vascular catheters, cerebrospinal fluid shunts, urinary catheters, continuous ambulatory peritoneal dialysis (CAPD) catheters, ophthalmic implants, etc.

By isolated D3D4 polypeptide is meant a polypeptide comprising substantially the entire D3 and D4 regions of Staphylococcus aureus Fbp, in sequence, optionally terminating in PIVP and optionally from one to five wall regions (WR) of

Staphylococcus aureus Fbp, in sequence, the polypeptide optionally terminating in PPIVPPT. The polypeptide may additionally comprise, in sequence, all or part of the D1 and D2 regions at the N-terminus, provided that no more than 50% of the D1 domain is present.

By 'substantially' is meant at least 80%, more preferably at least 90%, of the relevant domain.

For recombinantly produced polypeptides, depending upon the host expression system, the polypeptide may include an N-terminal methionine residue.

The above regions correspond to the following regions of FbpA as described in Signas et al. (1989), op. cit.:

In a preferred aspect, the polypeptide contains up to three wall regions.

The Fbp is preferably from Staphylococcus aureus J2385 with sequence given in Table 2.

The polypeptide of the invention may be prepared by proteolysis of longer lengths of Fbp proteins or polypeptides, for example the D 1 -D4 polypeptides disclosed inWO94/18327. Proteolysis may conveniently be achieved by treatment of the longer polypeptide with a protease. Specific proteolytic degradation of proteins is a commonly practised technique to those skilled in the art and is frequently applied to structure- activity-relationship (SAR) studies. Many proteases have been described in the scientific literature and those most commonly used in SAR studies include trypsin. chymotrypsin. elastase. and Staphylococcus aureus V8 protease. Less frequently used proteases include subtilisin, Proteinase K and plasmin. Which one is used for any particular experiment depends, to a large extent, on the nature of the protein and the size of the peptide fragments desired. For example, if biologically active fragments were wanted, the person skilled in the art would be more likely to choose an enzyme that cuts the parent protein only rarely. If the sequence of the parent protein is known it is possible to predict the number of fragments that may be generated by any one enzyme, used under optimal conditions. Such optimal conditions eg salt concentration. pH, temperature will vary from one enzyme to another. Sub-optimal conditions may be used to limit the number of cleavages generated by an enzyme that cleaves frequently. The concentrations of the enzyme and protein can be varied to alter the rate of cleavage. To assist subsequent purification/separation of the individual fragments a molar ratio of protein:enzyme of 100:1 is commonly employed. The enzyme may be free in solution or, to assist subsequent purification, may be immobilised on, for example, an agarose bead: after the reaction (cleavage) has taken place the beads are removed by centrifugation leaving the new peptides in the supernatant.

Methods used to purify and to separate the peptides are well known to those skilled in the art. Which method is employed will depend on the nature of the peptide(s), if known. For example, hydrophobic peptides may be separated using hydrophibic interaction chromatography, using ligands such as C₄ (butyl). Peptides rich in charged residues may be separated using ion-exchange matrices, for example CM (carboxymethyl) agarose. The conditions eg temperature, pH, salt

concentration (s) used are frequently best determined by experimentation.

The invention extends to such methods of preparation, comprising proteolysis of longer lengths of Fbp proteins or polypeptides and separation of the peptide of the invention.

Alternatively, specified D3D4 polypeptides may be prepared by conventional genetic engineering techniques.

This invention also provides isolated nucleic acid molecules encoding the polypeptide, including mRNAs, DNAs and cDNAs.

This invention also provides recombinant vectors, such as cloning and expression plasmids useful as reagents in the recombinant production of the polypeptides as well as recombinant prokaryotic and/or eukaryotic host cells comprising the novel nucleic acid sequence.

This invention also provides transgenic non-human animals comprising a nucleic acid molecule encoding the polypeptide.

A "replicon" is any genetic element (e.g., plasmid, chromosome, virus) that functions as an autonomous unit of DNA replication in vivo; i.e., capable of replication under its own control.

A "vector" is a replicon, such as a plasmid, phage, or cosmid, to which another DNA segment may be attached so as to bring about the replication of the attached segment.

A "double-stranded DNA molecule" refers to the polymeric form of deoxyribonucleotides (bases adenine, guanine, thymine, or cytosine) in a double- stranded helix, both relaxed and supercoiled. This term refers only to the primary and secondary structure of the molecule, and does not limit it to any particular tertiary forms. Thus, this term includes double-stranded DNA found, inter alia, in linear DNA molecules (e.g., restriction fragments), viruses, plasmids, and chromosomes. In discussing the structure of particular double-stranded DNA molecules, sequences may be described herein according to the normal convention of giving only the sequence in the 5' to 3' direction along the sense strand of DNA.

A DNA "coding sequence of" or a "nucleotide sequence encoding" a particular protein, is a DNA sequence which is transcribed and translated into a polypeptide when placed under the control of appropriate regulatory sequences.

A "promoter sequence" is a DNA regulatory region capable of binding RNA polymerase in a cell and initiating transcription of a downstream (3' direction) coding sequence. Within the promoter sequence will be found a transcription initiation site (conveniently defined by mapping with nuclease S1), as well as protein binding domains (consensus sequences) responsible for the binding of RNA polymerase. Eukaryotic promoters will often, but not always, contain "TATA" boxes and "CAT" boxes.

DNA "control sequences" refers collectively to promoter sequences, ribosome binding sites, polyadenylation signals, transcription termination sequences, upstream regulatory domains, enhancers, and the like, which collectively provide for the expression (i.e., the transcription and translation) of a coding sequence in a host cell.

A control sequence "directs the expression" of a coding sequence in a cell when RNA polymerase will bind the promoter sequence and transcribe the coding sequence into mRNA, which is then translated into the polypeptide encoded by the coding sequence.

A "host cell" is a cell which has been transformed or transfected, or is capable of transformation or transfection by an exogenous DNA sequence.

A cell has been "transformed" by exogenous DNA when such exogenous DNA has been introduced inside the cell membrane. Exogenous DNA may or may not be integrated (covalently linked) into chromosomal DNA making up the genome of the cell. In prokaryotes and yeasts, for example, the exogenous DNA may be maintained on an episomal element, such as a plasmid. With respect to eukaryotic cells, a stably transformed or transfected cell is one in which the exogenous DNA has become integrated into the chromosome so that it is inherited by daughter cells through chromosome replication. This stability is demonstrated by the ability of the eukaryotic cell to establish cell lines or clones comprised of a population of daughter cells containing the exogenous DNA.

A "clone" is a population of cells derived from a single cell or common ancestor by mitosis. A "cell line" is a clone of a primary cell that is capable of stable growth in vitro for many generations. A "heterologous" region of a DNA construct is an identifiable segment of DNA within or attached to another DNA molecule that is not found in association with the other molecule in nature.

This invention provides an isolated nucleic acid molecule encoding the polypeptide. The isolated nucleic acids particularly the DNAs can be introduced into expression vectors by operatively linking the DNA to the necessary expression control regions (e.g. regulatory regions) required for gene expression. The vectors can be introduced into the appropriate host cells such as prokaryotic (e.g., bacterial), or eukaryotic (e.g. yeast, insect or mammalian) cells by methods well known in the art ("Current Protocols in Molecular Biology", Ausubel, F.M., et al. (eds.) Greene Publishing Assoc. and John Wiley Interscience, New York, 1989,1992). The coding sequences for the desired proteins having been prepared or isolated, can be cloned into a suitable vector or replicon. Numerous cloning vectors are known to those of skill in the art, and the selection of an appropriate cloning vector is a matter of choice. Examples of recombinant DNA vectors for cloning and host cells which they can transform include the bacteriophage λ (E. coli), pBR322 (E. coli), pACYC177 (E. coli), pKT230 (gram-negative bacteria), pGV1 106 (gram-negative bacteria), pLAFR1 (gram-negative bacteria), pMΕ290 (non-E. coli gram-negative bacteria), pHV14 (E. coli and Bacillus subtilis), pBD9 (Bacillus), pIJ61 (Streptomyces), pUC6

(Streptomyces), YIp5 (Saccharomyces), YCp19 (Saccharomyces). See, generally, "DNA Cloning ": Vols. I & II, Glover et al. ed. IRL Press Oxford (1985) (1987) and T. Maniatis et al. ("Molecular Cloning" Cold Spring Harbor Laboratory (1982).

The gene can be placed under the control of a promoter, ribosome binding site (for bacterial expression) and. optionally, an operator (collectively referred to herein as "control" elements), so that the DNA sequence encoding the desired protein is transcribed into RNA in the host cell transformed by a vector containing this expression construction. The coding sequence may or may not contain a signal peptide or leader sequence. The polypeptides of the present invention can be expressed using, for example, the E. coli tac promoter or the protein A gene (spa) promoter and signal sequence. Leader sequences can be removed by the bacterial host in post-transiational processing. See, e.g., U.S. Patent Nos. 4,431,739;

4,425.437: 4,338,397.

In addition to control sequences, it may be desirable to add regulatory sequences which allow for regulation of the expression of the protein sequences relative to the growth of the host cell. Regulatory sequences are known to those of skill in the art, and examples include those which cause the expression of a gene to be turned on or off in response to a chemical or physical stimulus, including the presence of a regulatory compound. Other types of regulatory elements may also be present in the vector, for example, enhancer sequences.

An expression vector is constructed so that the particular coding sequence is located in the vector with the appropriate regulatory sequences, the positioning and orientation of the coding sequence with respect to the control sequences being such that the coding sequence is transcribed under the "control" of the control sequences (i.e., RNA polymerase which binds to the DNA molecule at the control sequences transcribes the coding sequence). Modification of the coding sequences may be desirable to achieve this end. For example, in some cases it may be necessary to modify the sequence so that it may be attached to the control sequences with the appropriate orientation; i.e., to maintain the reading frame. The control sequences and other regulatory sequences may be ligated to the coding sequence prior to insertion into a vector, such as the cloning vectors described above. Alternatively, the coding sequence can be cloned directly into an expression vector which already contains the control sequences and an appropriate restriction site.

In some cases, it may be desirable to add sequences which cause the secretion of the polypeptide from the host organism, with subsequent cleavage of the secretory signal.

A number of prokaryotic expression vectors are known in the art. See, e.g., U.S. Patent Nos. 4,578,355; 4,440,859; 4,436,815; 4,431,740; 4,431,739; 4,428,941; 4,425,437; 4,418,149; 4,411,994; 4,366.246: 4,342,832; see also U.K. Patent

Applications GB 2,121,054: GB 2,008,123: GB 2,007,675; and European Patent Application 103,395. Yeast expression vectors are also known in the art. See, e.g., U.S. Patent Nos. 4,446,235; 4,443,539: 4.430.428; see also European Patent

Applications 103,409; 100,561; 96,491. pSV2neo (as described in J. Mol. Appl. Genet. 1:327-341) which uses the SV40 late promoter to drive expression in mammalian cells or pCDNAlneo, a vector derived from pCDNAKMol. Cell Biol. 7:4125-29) which uses the CMV promoter to drive expression. Both these latter two vectors can be employed for transient or stable (using G418 resistance) expression in mammalian cells. Insect cell expression systems, e.g., Drosophila and Spodoptera, are also useful, see for example, PCT applications WO 90/06358 and WO 92/06212 as well as EP application EP0290261.

Depending on the expression system and host selected, the polypeptide of the present invention may be produced by growing host cells transformed by an expression vector described above under conditions whereby the polypeptide of interest is expressed. The polypeptide is then isolated from the host cells and purified. If the expression system secretes the polypeptide into growth media, the polypeptide can be purified directly from the media. If the polypeptide is not secreted, it is isolated from cell lysates or recovered from the cell membrane fraction. The selection of the appropriate growth conditions and recovery methods are within the skill of the art.

The invention also extends to a process for preparing a polypeptide of the invention comprising expressing DNA encoding said polypeptide and recovering the expression product.

The D3D4 polypeptide, or an antigenically or immunologically equivalent polypeptide or a fusion protein thereof may be used as an antigen to immunize a mouse or other animal such as a rat or chicken.

The term antigenically equivalent derivative' as used herein encompasses a peptide or its equivalent which will be specifically recognised by certain antibodies which, when raised to peptides according to the present invention, block adhesion of staphylococci to in-dwelling medical devices.

The term 'immunologically equivalent derivative' as used herein encompasses a polypeptide or its equivalent which when used in a suitable formulation to raise antibodies in a vertebrate, the antibodies act to block adhesion of staphylococci to indwelling medical devices.

In particular derivatives which are slightly longer or slightly shorter than the polypeptide of the present invention may be used. In addition, polypeptides in which one or more of the amino acid residues are modified before or after the polypeptide is synthesised may be used. Such polypeptides may, for example, be prepared by substitution, addition, or rearrangement of amino acids or by chemical modification thereof. All such substitutions and modifications are generally well known to those skilled in the art of peptide chemistry.

The fusion protein may provide stability to the polypeptide. The antigen may be associated, for example by conjugation, with an immunogenic carrier protein for example bovine serum albumin (BSA) or keyhole limpet haemocyanin (KLH).

Alternatively a multiple antigenic peptide comprising multiple copies of the the D3D4 polypeptide , or an antigenically or immunologically equivalent polypeptide thereof may be sufficiently antigenic to improve immunogenicity so as to obviate the use of a carrier.

Using the procedure of Kohler G. and Milstein C. (1975) Nature 256 , 495- 497, antibody-producing cells from the immunised mammal are fused with myeloma cells to create hybridoma cells secreting monoclonal antibodies.

The hybridomas are screened to select a cell line with high binding affinity and favorable cross reaction with other staphylococcal species using one or more of the D3D4 polypeptide and/or the fusion protein. The selected cell line is cultured to obtain the desired Mab. Hybridoma cell lines secreting the monoclonal antibody are another aspect of this invention.

Alternatively phage display technology could be utilised to select antibody genes with binding activities towards D3D4 either from repertoires of PCR amplified v-genes of lymphocytes from humans screened for possessing anti-Fbp or from naive libraries (McCafferty, J. et al, (1990), Nature 348, 552-554; Marks, J. et al, (1992) Biotechnology 10, 779-783). The affinity of these antibodies can also be improved by chain shuffling (Clackson. T. et al., (1991 ) Nature 352, 624-628).

Preferably the antibody or derivative thereof is modified to make it less immunogenic in the patient. For example, if the patient is human the antibody may most preferably be 'humanised' ; where the complimentarity determining region(s) of the hybridoma-derived antibody has been transplanted into a human monoclonal antibody , for example as described in Jones. P. et al (1986), Nature 321, 522-525 or Tempest et αl.,(1991) Biotechnology 9, 266-273.

The modification need not be restricted to one of 'humanisation' ; other primate sequences (for example Newman, R. et al .1992, Biotechnology,10, 1455- 1460) may also be used.

The antibody should be screened again for high affinity to D3D4 polypeptide and/or fusion protein.

The novel monoclonal antibodies and their fragments form a further aspect of the invention.

The antibody may be either intact antibody of M_r approx 150,000 or a derivative of it, for example a Fab fragment or a Fv fragment as described in Skerra, A and Pluckthun, A ( 1988) Science 240 1038-1040. If two antigen binding domains are present each domain may be directed against a different epitope - termed

'bispecific' antibodies.

The antibody or derivative thereof may be prepared by conventional means for example by established monoclonal antibody technology (Kohler, G. and Milstein, C. (1975), op. cit.) or using recombinant means e.g. combinatorial libraries, for example as described in Huse, W.D. et al, ( 1989) Science 246,1275- 1281.

Preferably the antibody or derivative is prepared by expression of a DNA polymer encoding said antibody in an appropriate expression system. The choice of vector for the expression system will be determined in part by the host, which may be a prokaryotic cell, such as E. coli or Streptomyces species or a eukaryotic cell, such as a mouse C127, mouse myeloma, human HeLa. Chinese hamster ovary, filamentous or unicellular fungi or insect cell. The host may also be a transgenic animal or a transgenic plant [for example as described in Hiatt, A et αl.,(1989) Nature 34, 76-78]. Suitable vectors include plasmids, bacteriophages. cosmids and recombinant viruses, derived from, for example, baculoviruses or vaccinia.

The Fab fragment may also be prepared from its parent monoclonal antibody by enzyme treatment, for example using papain, to cleave the Fab portion from the Fc portion.

The present invention further provides a monoclonal antibody (Mab), or a fragment thereof as above defined, in the prevention of adhesion of bacteria, in particular gram positive bacteria, to extracellular matrix proteins on in-dwelling devices or to extracellular matrix proteins in wounds and of oral pathogens to extracellular matrix proteins on surfaces in the oral cavity, in particular the acquired pellicle on tooth surfaces. The invention particularly relates to the manufacture of a medicament for such uses.

Another aspect of the invention is a pharmaceutical composition comprising the above polypeptide or Mab or active fragment and a pharmaceutically acceptable carrier.

In therapy or as a prophylactic, the polypeptide or Mab or active fragment may be administered to a patient as an injectable composition, for example as a sterile aqueous dispersion, preferably isotonic.

Alternatively the composition may be formulated for topical application for example in the form of ointments, creams, lotions, eye ointments, eye drops, ear drops, sprays, swabs, mouthwash, impregnated dressings and sutures and aerosols, and may contain appropriate conventional additives, including, for example, preservatives, solvents to assist drug penetration, and emollients in ointments and creams. Such topical formulations may also contain compatible conventional carriers, for example cream or ointment bases, and ethanol or oleyl alcohol for lotions. Such carriers may constitute from about 1 % to about 98% by weight of the formulation; more usually they will constitute up to about 80% by weight of the formulation.

The composition of the invention may be administered by injection to achieve a systemic effect against relevant bacteria shortly before insertion of an in-dwelling device. Treatment may be continued after surgery during the in-body time of the device. In addition, the composition could also be used to broaden perioperative cover for any surgical technique to prevent bacterial infections, such as staphylococcal wound infections.

Many orthopaedic surgeons consider that patients with prosthetic joints should be considered for antibiotic prophylaxis before dental treatment that could produce a bacteraemia. Late deep infection is a serious complication sometimes leading to loss of the prosthetic joint and is accompanied by significant morbidity and mortality. It may therefore be possible to extend the use of the polypeptide or Mab or active fragment as a replacement for prophylactic antibiotics in this situation.

For administration to human patients, it is expected that the daily dosage level of the active agent will be from 0.01 to 10 mg/kg, typically around 1 mg/kg. The physician in any event will determine the actual dosage and interval of dosing that will be most suitable for an individual patient and will vary with the age, weight and response of the particular patient. The above dosages are exemplary of the average case. There can, of course, be individual instances where higher or lower dosage ranges are merited, and such are within the scope of this invention.

With the indicated dose range, no adverse toxicological effects will be observed with the compounds of the invention which would preclude their administration to suitable patients.

In addition to the therapy described above, the compositions of this invention may be used generally as a wound treatment agent to prevent adhesion of bacteria to matrix proteins, especially fibronectin, exposed in wound tissue and for prophylactic use in dental treatment as an alternative to, or in conjunction with, antibiotic prophylaxis. Alternatively, the composition of the invention may be used to bathe an indwelling device immediately before insertion. The active agent will preferably be present at a concentration of 1μg/ml to 10mg/ml for bathing of wounds or indwelling devices.

For use in oral hygiene, a method according to the present invention is preferably carried out in a prophylactic manner, as pan of a normal oral hygiene regime.

The polypeptide or Mab or active fragment is thus of use in oral hygiene, in particular in combating the plaque - related development of carious lesions, gingivitis, calculus or periodontal disease and in combating oral cavity infections such as candidiasis. The fibronectin binding protein or polypeptide may also have a professional use at the time of oral surgery eg in guided tissue regeneration procedures in periodontal disease or osseointegrated implants to prevent subsequent bacterial infection. It may also be used for irrigation of periodontal pockets and/or incorporated into controlled release devices for administration to the periodontal pocket to prevent or treat periodontal disease progression. It may also be used as a denture cleaner to prevent candidiasis.

The mechanism by which oral pathogens adhere to an oral cavity surface can occur in a number of ways including direct attachment to a surface or by indirect attachment to a surface which may be already coated with a pellicle and/or

microorganisms already present on such surface. The fibronectin binding protein or polypeptide can thus prevent the binding of non-pathogenic early colonisers and binding and co-aggregation of an oral pathogen.

The term "preventing the adherence of oral pathogens to surfaces in the oral cavity" therefore means preventing the direct adherence of oral pathogens or preventing the adherence of non-pathogenic early colonisers thereby preventing the subsequent binding and co-aggregation of oral pathogens or even preventing the adherence of pathogenic oral organisms to non-pathogenic early colonisers.

In another aspect, the present invention provides an oral hygiene composition comprising the above mentioned polypeptide or Mab or active fragment and an orally acceptable carrier.

Suitable oral hygiene compositions are well known in the art and include dentifrices, including opaque and transparent/translucent toothpastes, liquid dentifrices, non-abrasive gels, mouthwashes, mouthrinses and gargles, mouthsprays, gingival irrigating devices, paint-on varnishes, formulations to be sucked or chewed by the user such as gums and lozenges and dental flosses.

Such compositions will contain appropriate formulating agents such as abrasives, surfactants, humectants, thickening agents, flavouring agents, sweetening agents, opacifying agents, preservatives and water, selected from those conventionally used in the oral hygiene composition art for such purposes and which are compatible with the polypeptide or monoclonal antibodies hereinbefore described.

Suitable surfactants for use in compositions according to the present invention include, for instance, anionic, nonionic, cationic and amphoteric surfactants or mixtures thereof.

Suitable anionic surfactants include alkali metal (C_{12 - 18})alkyl sulphates, for instance sodium lauryl sulphate, and N-acyl sarcosinates and N-acyl taurines in which the acyl moiety has from 12 to 16 carbon atoms, for instance, N-lauroyl, N-myristoyl and N-palmitoyl sarcosine alkali metal salts.

Suitable nonionic surfactants include, for example, polyethoxylated sorbitol esters, in particular polyethoxylated sorbitol monoesters, for instance, PEG(40) sorbitan di-isostearate, and the products marketed under the trade name Tween' by ICI: polycondensates of ethylene oxide and propylene oxide (poloxamers), for instance the products marketed under the trade name 'Pluronic' by BASF-Wyandotte; condensates of propylene glycol; polyethoxylated hydrogenated castor oil, for instance, cremophors; and sorbitan fatty esters.

Suitable amphoteric surfactants include, for example, long chain imidazoline derivatives such as the product marketed under the trade name 'Miranol C2M' by Miranol; long chain alkyl betaines, such as the product marketed under the tradename Empigen BB' by Albright + Wilson, and long chain alkyl amidoalkyl betaines, such as cocamidopropylbetaine, and mixtures thereof.

Suitable cationic surfactants include the D,L-2-pyrrolidone-5-carboxyhc acid salt of ethyl-N-cocoyl-L-arginate, marketed under the trade name CAE by Ajinomoto Co. Inc., and cocamidopropyl PG dimomum chloride phosphate and lauramidopropyl PG dimomum chloride phosphate, available under the trade names Monaquat PTC and Monaquat PTL, respectively, from Mona Corporation.

Advantageously, the surfactant is present in the range 0.005 to 20%, preferably 0.1 to 10%, more preferably 0.1 to 5% by weight of the dentifrice.

Suitable thickening agents include, for instance, nonionic thickening agents such as, for example, (C_{1 -6})alkylcellulose ethers, for instance methylcellulose;

hydroxy(C_{1 -6})alkylcellulose ethers, for instance hydroxyethylcellulose and hydroxypropylcellulose; (C_2-6)alkylene oxide modified (C_1-6) alkylcellulose ethers, for instance hydroxypropyl methylcellulose: and mixtures thereof. Other thickening agents such as natural and synthetic gums or gum like material such as Irish Moss, gum tragacanth, sodium carboxymethylcellulose, polyvinyl pyrrolidone, starch, xantham, carrageenan and thickening silicas may also be used.

Advantageously the thickening agent is present in the range 0.01 to 30%, preferably 0.1 to 15%, more preferbly 1 to 5%, by weight of the composition.

Suitable humectants for use in compositions of the invention include for instance, glycerine, sorbitol, propylene glycol or polyethylene glycol, or mixtures thereof: which humectant may be present in the range from 5 to 90%, preferably 5 to 70%, more preferably 10 to 50% by weight of the dentifrice.

Suitable abrasives for use in dentifrice compositions of the present invention include calcium carbonate, calcium phosphates, calcium pyrophosphate, insoluble sodium metaphosphate, sodium aluminosilicate, alumina, hydrated alumina, zinc orthophosphate, plastic panicles, and silica, of which silica is the preferred abrasive.

Suitable silicas include natural amorphous silicas, such as, for instance, diatomaceous earth, and synthetic amorphous silicas, such as precipitated silicas and silica gels, including silica xerogels. Suitable silica xerogels are described in US

3.538,230. Suitable grades of precipitated silicas have BET surface areas in the range 20 to 300, preferably 20 to 100 m²/g and median agglomerate sizes in the range 2 to 50, preferably 5 to 30μ.

Suitable precipitated silicas and silica xerogels are those marketed under the trade names Sident and Syloblanc, by Degussa and W R Grace Corporation Davison Chemical Division, respectively.

Advantageously, the silica is a "low anion" silica. As used herein, the term "low-amon" silicas refers to those in which anionic impurities such as sodium sulphate and sodium silicate which normally arise during the course of the manufacturing process are kept to a minium, through careful control of the manufacturing process. "Low anion" silicas suitably have less than 1%, preferably less than 0.5% advantageously less than 0.25% by weight of anionic impurities.

Suitable such "low anion" silicas are described in EP 0 368 130 (Proctor &

Gamble), EP 0 315 503 and EP 0 396 459 (Rhone-Poulenc) and WO 90/05113 (J.M. Huber Corp). Alternatively, grades of commercially available silica with ionic impurities may be rendered suitable by washing thereof with deionised water.

Conductivity measurements on the water after washing may be used to monitor the efficacy of such washing. Suitably the conductivity of the water after washing is reduced to less than 200μSiemens/cm. Suitable "low anion" silicas include the grade RP93 available from Rhone-Poulenc.

Suitably, compositions will have from 5 to 80%, preferably from 10 to 60% by weight of the abrasive.

Suitable mouthwash formulations will have an aqueous base comprising water or aqueous ethanol, and optionally a further liquid such as glycerin or propylene glycol. A surfactant may also be included, to improve the sensory properties of the composition. Mouthwash compositions may be provided in a "ready to use" form; as a concentrated solution, for dilution by the user immediately prior to use; or in solid form, such as a tablet or in a sachet, for dissolution by the user immediately prior to use. Tablets may suitably be prepared using xylitol and/or sorbitol as the major ingredient. The sachets and tablets may be formulated to provide, on dissolution, a still mouthwash, or, by the incorporation of a suitable effervescent couple, for instance sodium carbonate/bicarbonatre and citric acid, an effervescent mouthwash.

Oral hygiene compositions of the present invention may usefully further comprise an anti-caries agent, for instance a source of fluoride ions such as an alkali metal or amine fluoride salt, for example sodium fluoride, tin (II) fluoride.

Alternatively, the fluoride ion source may be an alkali metal monofluorophosphate salt, for example sodium monofluorophosphate. optionally used in combination with an agent such as calcium glycerophosphate which is known to enhance the activity of monofluorophosphate (GB 1 384 375, Beecham Group). Suitably the composition will comprise between 100 and 2500ppm. preferably 200 and 1500ppm of fluoride ions.

Oral hygiene compositions of the present invention may also comprise other active agents conventionally used in oral hygiene compositions, for instance:

an anti-plaque agent such as chlorhexidine. cetyl pyridinium chloride, triclosan, histatin or nisin (particularly in the purified form available as Ambicin N from Applied Microbiology Inc., New York); an anti-calculus agent such as a tetra- or a di-alkali metal pyrophosphate salt, or a mixture thereof, an alkali metal tripolyphosphate salt or an azacycloheptane diphosphonate salt; or

an anti-sensitivity agent such as strontium acetate, strontium chloride or a potassium salt such as potassium nitrate, potassium chloride or potassium citrate. Such agents will be included at levels to provide the desired therapeutic effect.

Oral hygiene compositions according to the present invennon will have a pH which is orally acceptable, for instance in the range pH 5 to 10.

Oral hygiene compositions according to the present invention may be prepared by admixing the ingredients in the appropriate relative amounts in any order that is convenient and thereafter and if necessary adjusting the pH to give the final desired value.

The poiypetide or Mab or active fragment will be incorporated into oral hygiene compositions according to the present invention at concentrations sufficient to provide the aforementioned daily rate eg 0.002% to 2.3%, preferably 0.23% (w/w).

With the indicated dose range, no adverse toxicological effects are expected with the compounds of the invention which would preclude their use.

The following Examples illustrate the preparation of D3D4 polypeptides for use as anti-adhesive agents.

Numbering of amino acid residues in the Examples

In the following examples the numbering of amino acid residues corresponds to the residues of the sequence of S. aureus J2385 given in Table 2. Residues 709- 838 of FbpA (Signas et al., ( 1989) op. at.) correspond to residues 1-130 of the sequence of S. aureus J2385 given in Table 2 and residues 709-886 correspond to residues 1- 174.

Example 1 Isolation of specific fragments of D1-D4 (G1-T181) Fragments of D1-D4 (G1-T181) (SEQ ID NO:7 herein, isolated as described in WO94/18327 and described therein as D1-D4 (709-886)) were obtained by limited plasmin digestion. Human lys⁷⁸-plasmingen (Immuno, Vienna) (0.2mg) was activated to plasmin by treatment with urokinase (Serono. UK) (20IU;

100,000IU/mg) for 1h at 37°C.

Purified D1-D4 (G1-T181) lyophilisate ( 18mg) was resuspended in 4.5ml

50mM NaH₂PO₄ pH6.0 containing 20% (^v/_v) glycerol, 0.8mg plasmin added and the reaction mixture incubated for 20h at 37°C. The reaction was terminated by the addition of phenylmethylsulphonyl fluoride to 1mM final concentration. The D1-D4 (G1-T181) reaction mixture (4.5ml) was mixed with 4M (NH₄)₂SO₄ (1.2ml) and applied to a Toyopearl Butyl column (TosoHaas) (i.d., 1.0cm; h, 1 1cm) equilibrated in 0.8M (NH₄)₂SO₄ / 0.1M NaH₂PO₄ pH7.0 (Buffer A). The column was then washed with approx. 3 bed volumes of Buffer A. The D1-D4 fragments that adsorbed to the matrix were eluted from the column using a 30% to 100% linear gradient of 0.1M NaH₂PO₄ pH7.0 in Buffer A over 10 column volumes. The separated D1-D4 fragments were identified by SDS PAGE, and then individually concentrated by centrifugation, using M_r10,000 cut-off membranes (Centriprep 10, Amicon), to 0.5ml retentates.

The separated D1-D4 fragments were identified by N-terminal sequence analysis and by electrospray mass spectroscopy. The fragments obtained were:- D1-D4(H81-T181) SEQ ID NO:3

D1-D4(Y58-T181) SEQ ID NO:4

D1-D4(D54-T181) SEQ ID NO:5

D1-D4(Y20-T181) SEQ ID NO:6

Example 2 Isolation of D1-D4 (P18-P130 (P130T))

D1-D4 (P18-P130 (P130T), SEQ ID NO: 1 ) was obtained by limited E.coli protease digestion of D1-D4(G1-P130 (P130T), SEQ ID NO:8 herein, isolated as described in WO94/18327 and described therein as D1-D4 (709-838(P838T)) during the culture of and/or isolation of the full length molecule. The title compound was separated from the full length molecule by purification on Butyl Toyopearl, as described in WO94/ 18327.

Example 3 Isolation of D1-D4 (P18-T181)

D1-D4 (P18-T181) (SEQ ID NO:2) was obtained by limited E.coli protease digestion of D1-D4(G 1-T181) during the culture of and/or isolation of D1-D4(G1- T181 ). D 1-D4 (P18-T181 ) was separated from intact D1 -D4 (G 1 -T181) by purification on Butyl Toyopearl, as described in PCT/GB94/00215. Example 4 Effect of plasmin fragments of D1-D4 on adhesion of

Staphylococcus aureus to fibronectin-coated polymethylmethacrylate (PMMA) coverslips in vitro. (i) Bacterial strain

Staphylococcus aureus 120

(ii) Adhesion assay

The in vitro adhesion assay described by Vaudaux et al ., Infection and Immunity 45:768-774, 1984, was used to measure staphylococcal adhesion to fibronectin-coated surfaces and to test the anti-adhesive properties of the D1-D4- derived polypeptides.

(iii) Preparation of bacteria

Staphylococcal cells were grown overnight at 37°C in Mueller-Hinton Broth

(MHB, Difco Laboratories). A total of 2 x 10⁷ cfu from the overnight culture was incubated with 100μCi [methyl -³H]-thymidine (Amersham) in 1ml of MHB and grown for 3 hours at 37°C up to 1 x 10⁸ - 2 x 10⁸ cfu/ml. After removal of the unbound radioactivity by two washes (3,000 x g, 10 minutes) the labelled cells were suspended in 1ml of 0.15M NaCl.

(iv) Adsorption of fibronectin to PMMA coverslips

All PMMA coverslips (0.75cm x 0.75cm) were immersed in 95% ethanol for

10 minutes at 37°C, drained and heated at 120°C for 30 minutes. The coverslips were then preincubated with gelatin ( 1mg/ml. Difco Laboratori es) for 60 minutes at room temperature and rinsed with PBS (without Ca²⁺-Mg²⁺, Gibco Laboratories).

Coverslips were immersed in solutions containing purified human fibronectin at

4μg/ml, for 60 minutes at 37°C. Coverslips were transferred to fresh tubes containing PBS and washed.

(v) Adhesion assay

D1-D4 fragments were diluted to the required concentration in PBS supplemented with cations (Gibco Laboratories) and albumin (20%, Sigma)

(PBS⁺⁺/HSA). Washed radiolabelled culture (40μl) was added to 960μl of the diluted D1-D4 fragment in plastic tubes. Fibronectin-coated coverslips were added to the bacterial suspensions and incubated at 37°C for 60 minutes with shaking

(100cycles/minute) Fluids were then drained away, coverslips transferred to fresh tubes, washed twice with saline ( 1ml) at room temperature for 1x5 and 1x30 minutes. Fluids were drained away and coverslips transferred to scintillation vials supplemented with 5ml scintillation fluid and counted.

(vi) Evaluation of cpm and cfu.

Portions of the 3 hour radiolabelled culture (10μl) were counted in scintillation vials. 100μl Aliquots were diluted 1 in 10,000 and 20μl plated onto Mueller-Hinton agar and viable counted. In addition, the cpm content of the 100μl of the diluted strain used in the adhesion assay was also checked to enable the numbers of cfu's adhering to fibronectin-coated PMMA coverslips to be calculated.

(vii) Results

The dentifrice base may be used to provide a dentifrice comprising a D3D4 polypeptide 0.2, 0.5, 1, 1.5 or 2% .

The dentifrice base may be used to provide a dentifrice comprising a D3D4 polypeptide 0.2. 0.5, 1, 1.5 or 2%.

Table 1 A Comparison of the DNA Encoding the Fibronectin Binding Domains of S. aureus Fibronectin Binding Protein type A and of the S. aureus J2385 DNA sequence.

Table 2 A comparison of the derived amino acid sequences of the Fibronectin

Binding Regions of the Fibronectin Binding Proteins of

Staphylococcus aureus (as published) and Staphylococcus aureus J2385.

The Staphylococcus aureus sequence a comprises amino acid residues 709-886 (as in

Signas et al. loc. cit.)

Claims

1. An isolated D3D4 polypeptide from a Staphylococcus aureus Fbp.

2. A polypeptide according to claim 1 comprising substantially the entire D3 and D4 regions of Staphylococcus aureus Fbp, in sequence, optionally terminating in PIVP and optionally from one to five wall regions (WR) of Staphylococcus aureus Fbp, in sequence, the polypeptide optionally terminating in PPIVPPTpolypeptide consisting of the entire D2 and D3 regions of Staphylococcus aureus Fbp, in sequence.

3. A polypeptide according to claim 2 additionally comprising, in sequence, all or part of the D1 and D2 regions at the N-terminus, provided that no more than 50% of the D1 domain is present.

4. A polypeptide according to claim 2 or 3 containing up to three wall regions.

5. A polypeptide according to any preceding claim wherein the Fbp is from 5. aureus J2385.

6. A polypeptide according to claim 1 having a sequence selected from SEQ ID NO: 1 , SEQ ID NO:2. SEQ ID NO:3. SEQ ID NO:4, SEQ ID NO:5 and SEQ ID NO:6.

7. Isolated nucleic acid encoding the polypeptide of any one of claims 1 to 6.

8. A recombinant vector comprising the isolated nucleic acid of claim 7.

9. A host cell transformed with the vector of claim 8.

10. A process for preparing the polypeptide of any one of claims 1 to 6

comprising expressing DNA encoding said polypeptide and recovering the expression product.

1 1. A process for preparing the polypeptide of any one of claims 1 to 6 by proteolysis of longer lengths of Fbp proteins or polypeptides.

12. A monoclonal antibody (Mab) that binds to an Fbp, obtainable using the D3D4 region of an Fbp or polypeptide that is an immunologically or antigenically equivalent derivative of the D3D4 region as antigen.

13. A monoclonal antibody according to claim 1, wherein the Fbp is from S. aureus J2385 (NCIMB 40532).

14. A monoclonal antibody according to claim 12 or 13, which has been humanised.

15. A polypeptide which is a fragment of a monoclonal antibody according to any one of claims 12 to 14 that comprises the binding region of the Mab.

16. A polypeptide that is a derivative of a polypeptide according to any of claims 1 to 6 and has equivalent immunological or antigenic activity.

17. A process for preparation ot monoclonal antibodies in which an animal is immunized with a polypeptide according to any one of claims 1 to 6 or 16, antibody producing cells of the animal are fused with cells of a continuous cell line, and the hybridoma cells are cloned and screened to select clones producing antibodies according to any one of claims 12 to 14.

18. A hybridoma cell line that secretes an antibody according to any one of claims 12 to 14.

19. A method of purifying a polypeptide as defined in any one of claims 1 to 6, 15 or 16 from a sample, comprising immobilizing monoclonal antibodies capable of specifically binding said polypeptide on a substrate, contacting the sample with the immobilised monoclonal antibodies under suitable conditions such that the polypeptide binds to said antibodies, separating unbound sample and eluting the polypeptide from the immobilised monoclonal antibodies.

20. Use of a monoclonal antibody as defined in any one of claims 12 to 14 for the qualitative or quantitative determination ot a polypeptide as defined in any one of claims 1 to 6, 15 or 16.

21. A test kit for the determination of a polypeptide as defined in any one of claims 1 to 6, 15 or 16 comprising a monoclonal antibody according to any one of claims 12 to 14 and optionally other monoclonal or polyclonal antibodies and / or adjuncts in a suitable package.

22. A pharmaceutical composition comprising a monoclonal antibody according to any one of claims 12 to 14 or a polypeptide according to any one of claims 1 to 6 or 15 and a pharmaceutically acceptable earner.

23. Use of a polypeptide according to any one of claims 1 to 6 or 15 or a Mab according to any one of claims 12 to 14 in the manufacture of a medicament for use in the prevention of adhesion of bacteria to extracellular matrix proteins on indwelling devices or to extracellular matrix proteins in wounds and of oral pathogens to extracellular matri x proteins on surfaces in the oral cavity.

24. A method of preventing adhesion of bacteria to extracellular matrix proteins present on indwelling devices which comprises treating a patient before, during or after surgery to install the device with an effective amount of a polypeptide according to any one of claims 1 to 6 or 15 or a Mab according to any one of claims 12 to 14.

25. A method of preventing adhesion of bacteria to extracellular matrix proteins present in wounds which comprises treating a wounded patient with an effective amount of a polypeptide according to any one of claims 1 to 6 or 15 or a Mab according to any one of claims 12 to 14.

26. A method of preventing adhesion of oral pathogens to extracellular matrix proteins on surfaces in the oral cavity which comprises treating a patient with an effective amount of a polypeptide according to any one of claims 1 to 6 or 15 or a Mab according to any one of claims 12 to 14.

27. A use or method according to claim 23, 24 or 25 wherein the bacteria are gram positive bacteria.