LV12233B - Receptor conjugates for targeting drugs and other agents - Google Patents

Abstract

Conjugates that purposefully transport medications to the organism, for example antibacterial drugs, are described. Specifically they couple the drug substance with the infection carriers' specific receptors. Methods of using and obtaining the conjugates are described.

Description

LV 12233

Description Technical FiefcJ

The present invention relates generally to conjugates comprising an aģent, such as an anti-infective, coupled to a receptor whic" binds a microorganism. and to methoas ior making and using these conjugates.

Backoround & the Invention A reoccurrīng problem īn medicine is that, due to the lack of specificity of tne aģents used for treatment of illnesses, the patient is often the recipient of a new set of maladies from the therapy. This scanario is common and has occurred in the treatment of infections due to pathogenic microorganisms.

The conventionai approach to attempting to minimizē adverse sioe-effects o* an anti-microbial aģent, such as a drug. to a patient has been to prepare a myriad of Chemical derivatives in whicn moieties are added and/or deleted. The derivātives are then assessed for their effectiveness as well as their toxicity. Such an approach to minimizing adverse side-effects has been costly, time-consuming, and not always successful.

Due to the difficulties in the current approaches to the preparation of anti-microbial aģents which exhibit minimal side effects. there is a need in the art for such aģents. The present invention fills this need, and further provides other related advantages.

Summarv of the Invention

Briefly stated. the present invention provides a variety of conjugates useful as :r vitro inhibitors. such conjugates are also disclosed as therapeutic aģents. e.g.. for the treatment of infections due tc pathogenic microorganisms. The microorganism receptor-agent conjugates comprise at least one aģent coupled to at least one glycolipid. the glycolipid being capable of selectively binding a bacterial microorganism.

In one embodiment. the conjugate includes an aģent vvhich is an anti-infective. Preferred anti-infectives include antibiotics, synthetic drugs and steroids. In another embodiment, the conjugate includes an aģent vvhich is a molecule that inducēs neutralization of the microorganism. for example, by stimulating the proauction of antibodies. VVithin a related aspect, the present invention provides methods for inhibiting a microorganism in an in vitro biolog-ical preparation. In one embodiment. the method comprises contacting an in vitro biolooical preparation with an effec-tive amount of a microorganism receptor-agent conjugate, vvherein the conjugate comprises at least one aģent coupled to at least one glycolipid, the glycolipid being capable of selectively binding a bacterial microorganism.

There are disclosed methods for the treatment of infections due to pathogenic microorganisms. In one embodiment, the method comprises administering to a vvarm-biooded animal an effective amount of a conjugate described above, vvherein the glycolipid is capable of selective!y binding a pathogenic microorganism. A preferred vvarm-biooded animal is a human.

These and other aspects will become evident upon reference to the follovving detailed description and attached dravvings.

Brief Description of the Dravvinos

Figurē 1 depicts a flovvchart illustrating a procedure for the preparation of microorganism conjugates of the present invention in vvhich the aģent portion is a drug.

Figurē 2 shovvs a diagram illustrating the cross-linking of amoxicillin to the glycolipid receptor asalo-GM, using a photoreactive linker.

Detailed Description of the Invention

As noted above. the present invention provides microorganism receptor-agent conjugates and methods for using the conjugates in vitro. There is also disclosed use of the conjugates as therapeutic aģents, e.g., for the treatment of infections due to pathogenic microorganisms. These conjugates. in vvhich at least one aģent is coupled to at least one glycolipid, have enormous potential as potent anti-microbial eomposrtions. This is due to the selectivitv imparted to the conjugate by the glycolipid portion. The selectivity of the glycolipid permits increased targeting and soecificity for the pathogen. In addition, targeting of artti-microbial aģents by using the conjugates of the present invention minimizēs the dosage and adverse side-effects, such as the accumulation of toxic drugs in vītai orgāns, in a patient

Glycolipids on a host celi may function as receptors for the recognition and attachment of microorganisms to the host celi. The active part of a glycolipid receptor, i.e.. the minimum binding epitope, appears generaliy to he the carbo- 2 hydrate moiety. Therefore, the targedng portion fglycolipid receptor") of the conjugates of the presenl invention com-prises a glycolipid. Glycolipid receptors of the present invention include ourified receptors or portions thereof, synthetically prepared receptors or portions thereof, and derivatives of receptors or portions thereof. Such a glycolipid receptor is capable of selectively bindng a bacterial microorganism Recognition and attachment of microorganisms to host celis ts the result of specific interactions, between moiecules or the microorganisms and microorganism receptors on the hcs: celis, that permit the receptors to selectively bind microorganisms More than one pathogemc microorganism may omd to the same epitope e g., carbohydrate sequence. r orde· tc i~ect celis. Conversely, a microorganism may have jmque receptor specificir es. In either situation, a microo'gansm is :~ecting a host celi by selectively binding to a microorganism receptor. The omding of many microorganis.ms to g vcooc receptors is generally half maximal (B1/2 max: within a range of about 0.C2-0.2 micrograms of purified receotor =o- sxample. for Srreptococcus oneumomae about 0.0= ug of immobilized asialo-GM-, results in half maximum bnding anc -ielicosac:sr pyiori requires about 0.1 μg of immooiiized receptor.

Glyco»pid receptors for microorganisms may be purified from nost celis b> Standard biochemical techniques. For example, glycolipids may be purified by the methods described by Karissor fMeth. Enzvmol. 122:212-219, 1987).

Briefly, body fluid or celis are extra~ed with one or more organic soivents anc tne extract is subjected to mild alkaline degradation. Following neutraiization and dialysis. the lipids and giycolipids are separated by a series of chromatogra-phy technjques, e.g., silicic add and ion-exchange chromatography. The preparative steps are typically checked by thin-layer chromatography. (TLC). Purified. intact receptors may be usec to prepare tne conjugates of the present invention. Alternativeiy, it will be evident to one skilled in the art that, using Chemical, and/or enzymatic, reaģents and techniques, an intact receptor may be cleaved (to yield a portion thereof) and/or structurally modified (to yield a derivative of an intact receptor or portion thereof). A representative example is tne purification of asialogangiiosides (Krivan et al., Proc. Nati. Acad. Sci. USA 25:6157-6161, 1988). Briefiy. fucosviasiaio-GM·, and asialo-GM- were prepared from bovine brain gangliosides by hydrolysis in 25 mM H2S04 for i .5 hours at 80°C. The hydrolysis was neutralizec with NH4OH and dried under nitrogen, the residue was dissolved in chloroform/methanolMater (60:30:4.5. vol/vol), and non-glycosphingolipid contaminants were removed by Sephadex G-25 coiumn chromatography (Wells e: ai., Biochemistrv 2:1259-1263, 1963). Fucosylasi-alo-GM. and asialo-GM-, were separated from residual gangliosides by coiumr, chromatography on DEAE Sepharose and further purified by continuous thin-layer chromatography (Young et al., Meth Enzvmol. 138:125-132. 1987) on pre-parative siiica gel G plates with chloroform/methanol/vvater (75:18:2.5, vol/vo!) as the mobile phase. Asialo-GM2 was obtained after digestion of asialo-GM: with bovine testes β-galactosidase (0.5 unit/ml) for 36 hours ai 37°C in 0.1 M acetate buffer (pH 5.0) containing C.2% sodium taurocholate. Polar contaminants anc aetergent were removed by Sephadex G-25 and DEAE-Sepharcse coiumn chromatography. respeciively.

Alternatively, once the receptor structure has been identified. it may be orepared synthetically using Chemical, and/or enzymatic, reaģents and techniques. Similarly, the carbohydrate moiety of a receptor may be isolated from host celis or, follovving structural determīnation, prepared synthetically. Similar to the discussion above regarding purified receptors or portions thereof, structurally modified receptors or portions thereof may be prepared synthetically.

Briefly. in the case of enzymatic synthesis of carbohydrates, natūrai unprotected mono-, di- or oligosaccharides and stātie acids are used as starting materiāls. Properly activated derivatives thereof in the anomeric center may have to De used. The glycoside synthesis is hereafter carried out with the help of specific enzymes. In the case of Chemical syn-thesis, the same starting materiāls described above or derivatives thereof can be used. in this case, proper preactiva-tion of the anomeric center together with proper specific protection of the remaining hydroxyls has to be performed prior to use in specific glycoside synthesis. For example. five hydroxyl groups of a hexose may be converted to -OR· through -OR5, with R2-R5 representing protective groups. If the compound is used as the glycosyl donor, R, is a group that is suitable for activation in a glycoside synthesis by a different catalyst. Exampies of such groups are halides, sulfur derivatives, acetimidates and orthoesters. Conversely, if the compound is used as the glycosy! acceptor, R. can be a pro-tecting group as described below. R: can also be ehosen in a way such that it can be converted in a later step into a group as described above. A third possibility is that R1 is a ligand suitable for further coupiing to other compounds.

Protecting groups from diverse arts may be employed when the derivative is used as the glycosyl donor. Commonly used protecting groups are, for example. acetyis, benzyls. benzoates and acetais. If the compound is used as the giy-cosyl acceptor. one or several of the hydroxyls is unprotected in order tc render them accessible in the glycoside syn-thesis. It is well knovvn in the art to ehoose the protecting groups such tnat the hydroxyls are selectively deblocked in order to continue an oligosaccharide synthesis. R2*Rs may also be other protected carbohydrate residues or other sub-stituents or functional groups. The glycosyl donor and the glycosyl acceotor may be reacted together in the presence * of a suitable catalyst to create the desired glycosidic bond. Depending on how the protecting groups, the anomeric group, the catalyst and the reaction condition are ehosen, stereoselecovity and the desired stereochemistry can be obtained. If desired, this protected product can be deprotected to the free oiigosaccharide. If further reactions are to be carried out. this can be done by proper selection of the starting materiais which facilitates other glycosidation reaction by selectively manipulating the protecting groups and the anomeric center. This can be done both with a stepwise or a 3 LV 12233 btockwise approach. The hydroxyl substnuents may aiso be changed intc other funcnonal groups or attached to a ligand suitable for coupling.

Other representative examples of receptors for microorganisms include the follovving molecules. Cryptococcu$ neoformans. Candida albicans. and other fungi bind specifically to the glycosphmgolipid lactosylceramide (Jimenez-Lucho et al.. Infect. and Immun. 58:2085-2090.1990). Isolated as wel' as synthetic lactosylceramides are commercially available (e.c.. Sigma Chem. Co.. St. Louis. Mo. and Calbiodiem-Berng. La Jol.a Caiif.). Mycopiasma oneumoniae bind specifically to sulfatide and other suifated glycolipids (Krivan et s J Bioi Cnem. 264:9283-9288. 1989), as well as to sialylateo glycoproteins (Roberts e: al.. J. Biol. Chem 264:9289-5293. * 385' Sulfated glycolipids may be purified as describec oy Krivan et al. or obtainec commerciall) (e.g., Supelcc 5imiia.-iy. s.alylated glvcoproteins may be purified accordinc to Roberts et al. or obtainad commercially (e.g.. Sigma Cnem. Co. influenza virus binds specifically to sialic acid (Weis et al.. Nature 333:426-431. 1988). Rotaviruses bind soecificaliy tc the neutral glycosphingolipid asialo-GM-, (Willoughby et al., J. Virol. 64:4839-4835. 1990).

In addition to at least one glycolipd. the conjugates of the present invention mclude at least one aģent vvhich directly or indirectly inhibits microorganisms. A variety of aģents are sucable. For example, in one embodiment, one or more aģents vvhich are cytotoxic to a microorganism are coupled to a microorganism receptor to create a conjugate that may be termed a "receptor drug.” Preferred aģents are the classes of anti-irrfectives. such as antibiotics and synthetic drugs. that are efficacious in the treatment of infections due to pathogenic microorganisms. Representative antibacte-rial aģents include aminoglycosides, polymyxins, sulfonamides, mercnidizole. trimethoprim-sulfamethoxazole, and penicillins. A representative antiviral aģent is acyclovir. Representative antifunga! aģents include amphotericin B, nys-tatin and 5-fluorocytosine. Representative antiparasitic aģents include pentamidine and nitoimidazoles. Other aģents vvhich may be useful include steroids such as corticosteroids, e.g., precnisone, prednisilone and dexamethasone. The receptor drugs of the present invention p'ovide an efficient drug targeiinc system tr.at specifically eliminates pathogens by. for example, "fooling" the pathogen into binding to an artificial recepte- (i.e.. one coupled to a cytotoxic aģent) rather than to a natūrai receptor on a host celi. Alternatively, pathogens may aiready be attached to host celis and the receptor drugs of the present invention may bind to the pathogens via, for exampie. extra, soecific molecules on the pathogens that are not bound to the receptors.

The conjugates of the present invention, in another representative embodiment, include a molecule that inducēs neutralization of a microorganism. For example, the aģent may be a molecule vvhich stimulates the produetion of anti-bodies. Because, for example, carbohyarate receptors for pathogenic microorganisms are typically small and occur nat-urally on host celis, they are usua!ly not immunogenic. Hovvever, a microorganism receptor can be coupled to a carrier molecule, such as keyhole limpet hemocyanin, that confers immunogenicity. Consequently, when a pathogenic microorganism binds to this type of receptor conjugate, the pathogen becomes attachec vra the receptor portion of the conjugate to a molecule vvhich stimulates the produetion of antibodies by the host. Binding of antibodies to the pathogen via the conjugate sets in motion a sequence of events, the end result of which is neutralization of the pathogen.

An aģent may be coupled to, e.g.. covaiently bonded to, a glycolipid receptor either directly or indirectly, e.g., via a linker group. A direct reaction betvveen an aģent and a receptor is possiole when each possesses a substituent capable of reacting with the other. For example, a nucleophiiic group, such as an amino or suifhydryl group, on one may be capable of reacting with a carbonyl-containing group, such as an anhydride or an acid halide, or wrth an alkyl group contain-ing a good leaving group, e.g., a halide, on the other.

Alternatively, it may be desirable to couple an aģent and a receptor via a linker group. A linker group can funetion as a spacer to distance a receptor from an aģent in order to avoid interference with binding capabilities, e.g., by steric hindrance or conformational changes. A linker group can also serve to inerease the Chemical reactivity of a substituent on an aģent or a receptor, and thus inerease the coupling efficiency. An inerease in Chemical reactivity may also facili-tate the use of aģents, or functional groups on aģents, vvhich othervvise vvouid not be possible. A carboxyl group. for example, may be activated. Activation of a carboxyl group ineludes formation of an "active ester," such as a succinimidyl ester. The term "active ester" is knovvn to refer to esters vvhich are highly reactive in nucleophiiic substitution reactions.

It vvill be evident to one skilled in the art that a variety of bifunctional or polyfunctional reaģents, both homo- and hetero-functional (such as those deseribed in the Pierce Chemical Co. catalog), may be employed as the linker group.

Coupling may be effected, fpr example, through amino groups, carboxyl groups, sulfhydryl groups or oxidized carbohy-drate residues. There are numerous references deseribing such methodology. e.g.. U.S. Patent No. 4,671.958, to Rod-well et al.

Where an aģent is more potent when free from the receptor portion of the conjugates of the present invention, it may be desirable to use a linker group vvhich is cleavable, e.g., bio-cleavable. A number of different cleavable linker / groups have been deseribed previously. The mechanisms for release of an aģent from these linker groups include cleavage by reduetion of a disutfide bond (e.g., U.S. Patent No. 4,489,710. to Spitler), by irradiation of a photolabile bond (e.g., U.S. Patent No. 4,625,014, to Senter et al.), by hydrolysis of derivatized amino acid side chains (e.g., U.S.

Patent No. 4,638,045, to Kohn et al.), by serum complement-mediated hydrolysis (e.g., U.S. Patent No. 4,671,958, to Rodvvell et al.), and acid-catalyzed hydrolysis (e.g., U.S. Patent No. 4,569,789. to Blattler et al.). 4

It may be desirabie to couple more than one aģent to a glycolipia receptor. ir one embodiment, multiple moiecules of an aģent are coupled to one receptor molecule. In another embodiment more than one type of aģent may be coupled to one receptor. Regardless of the particular embodiment. conjugates with more than one aģent may be prepared in a variety of ways. For example, receptors with multiple sites for attachment of aģents can be coupled directly. or linkers which provide multiple sites for attachment can be used. Alternatively, a came* can be used. A carrier may bear the aģents in ε variety of ways, includinc covaient bondmc either directlv o: via a lm*;e· group. Suitable carriers include proteīns sucr as albumins (e.g.. U.S. Patent No. 4.507.234, to Kāto e: ai.), peotioe; and poiysaccharides such as amino-dextran (e.g. U.S. Patent No. 4,59975-4, to Shih et a ). A carrier ma> also osa- 5" aģent oy noncovalent bondmg or by encapsuiaton, such as within a iiposome (e.g., U.S. Patent Nos. 4,429,008 anc <4873.038) Similarly, it may be desirabie to inciuoe more than one receptor in a conjugate The above aiscussion rega-ding aģent is applicable here as well. For examDie a conjugate may be proauced in whicr multiple moiecules of a receotor are coupled to a Iiposome carrier (e.g., incorcorated into a Iiposome membrane) whicr encapsuiates (i.e., traps nside the iiposome vesicle) an aģent or aģents. A recresentative example is asialo-GM.-containing liposomes encaosu.atng amoxicillin, metronidazole, and/or bismuth subsalicylate.

As'noted above, there are disclosed methods o‘ using the conjugates descnoed above. In one aspect. the method comprises administering to a warm-biooded animai, such as a human, an effective amount of these conjugates. It will be evident tc one skilled in the art that the site of infection will be the most imponant faaor in determining not only the choice of the particular conjugate. but also the route by vvhich it should be admimstered. For instance, a fungal infection of the skin may be treated by topical administration and a bacterial infection of tne ears by oral administration. Methods of administration include oral, intravenous, intramuscular, topical and rectal. For ra! administration, the conjugates may be in pili, capsule or liquid form. For any method of administration, the conjugates may be combined with a physioloai-cally acceptable carrier or diluent, such as water or physiologicai saiine.

By aaministering to a warm-blooded animai an effective amount of a conjugate of the present invention, treatment of an infection due to a pathogenic microorganism is effected. The causative aģent of an infection may be bacteria, viruses, mvcoplasma, fungi orparasites. Representative bacteria include the g'ām-negative. gram-positive, anaerobes, spirochetes. mvcobacteria and actinomyces. Representative viruses inciude RNA and DNA viruses, e.g., herpes. cytomegaiovirus, influenza, hepatitis. RSV and HIV. Representative mycoplasmataceae include M. pneumonies. M. hominus. J'eaolasma and Acoleplasma. Representative fungi include Canc.za Crvprococcus, Coccidioiaes. Spo-rothnx. AsoergiHus and Hisroplasma. Representative parasites include protccoa (e.g., trhichomonas. pneumocvstis and entomoeba) and helminths (e.g.. nematodes and trematodes). Other patnogenic microorgantsms inciude the chlamydia,rickettsia group, e.g.. C. trachomatis. C. psdtaci. C. pneumoniae (TVvAR). RiCKSttsis and Coxiel!s bacteria.

The mechanism by which a pathogenic microorganism is neutralized depercs upon the type of aģent in a oarticular conjugate. For example, certain aģents, such as those vvhich stimulate the proauction of antibodies. work in conjuncticn with existing host celi defense mechanisms. Alternatively, other aģents, such as tnose vvhich are cytotoxic, may inacti-vate the microorganism more directly.

The precise dose for a particular conjugate may vary, depending upon the agsni and the receptor used In particular, aģents vary with respect to their potency and receptors vary with respect tc omding affinity Generally, hovvever, an effective amount of a conjugate of the present invention will be from about 0. * tc aoout 10 mc per kg body weight. It will be evident to one skilled in the art how to determine the optimal effective dose fo' a particular conjugate. For example. the effective amount may be determined based upon m vitro experiments, followea by ir vivo studies. Such methodol-ogies include measuring the minimal inhibitory concerttration (MIC) and mimma bactēriocidal concentration (MBC) The principle of the MIC. for example. is to determine the lovvest or minimal concentration of antimicrobial aģent that is required to inhibit the grovvth of a particular microorganism in vitro, and is usually exDressed in micrograms per milliliter Approved standards have been published by the National Committeefor Clinica’ _aboratory Standards (National Com-mittee for Clinical Laboratory Standards. Methods for Diiution Antimicrobial Susceptibility Tests for Bacterial That Grow Aerobically. Tentative Standard NCCLS Publication M7-T2. Villanova, PAtNCCLS 1988). For determination of the opti-mal effective amount of receptor drug m v/vo. diiution of serum that is inhibitorv 0' oacteriocidal to an organism isolated from a patient receiving the drug is analyzed. Proposed guidelines for performmg a serum baoteriocidal tēst have been published by the National Committee for Clinical Laboratory Standards (Nationa: Committee for Clinical Laboratory Standards Methodology on Serum Bacteriocida! Tēst. Proposed Guideline NCCLS Document Μ2Ί-Ρ Villanova. PAtNCCLS, 1987).

The particular conjugate admimstered is dependent on the nature of the infection or microorganism tnat is to be targeted. Determining the nature of an infection may be accomplished by a variet) of knovvn iechmques. such as assays using body fluīds For example, several immunologic methods for detection of microbial antiaens are available. including enzyme immunoassay, latex agglutination, coagglutination, counterimmunoelectrophoresis, fiuoroimmunoassay, and radioimmunoassay. Ali of these methods detect a particular microbial antigen, i.e.. a toxin, that infers the presence of a particular microorganism and cause of the disease. Other methods vvhich may be used alone or in conjunction with immunologic assays include direct culture. microscopy, biochemical and antimicrobial susceptibility testing. In the r LV 12233 embodiment where the aģent is an antibiotic or synthetic drug, a compound vvhich is efficacious for a particular infection is coupled to the appropriate receptor. For example, amoxicillin is used to treat pneumonia because it affects the growth of Streptococcus pneumoniae. In preparing a receptor drug for treating pneumonia. amoxiciltin may be covalently coupled to asialo-GM1 oligosaccharide. the carbohydrate structure which is the receptor for the organism. Other examples 5 of receptor drugs vvithin the present invention include a lactosylceramide-amphoteridn B conjugate for use against fungi (e.g., Candids or Cryptococcus) and a su!fatide-tetracycline or sulfatide-erythromycin conjugate for use against myco-plasmas. Examples of the drugs currerttly of choice for representative microorganisms are listed in Table 1 beiow. 10

1S 20

Table 1 Drug of Choice Microorganism Class of Organism Amphotericin B Candida, Cryptococcus Fungi (yeast) Metronidazole Trichomonas Protozoan Amoxicillin Helicobacter pylori (formerly Campy/obacrer pyiori) Bacteria Ampicillin/Amoxicillin Streptococcus pneumoniae Bacteria Tetracycline/Erythromycin Mycopiasma pneumoniae Mycoplasma Tetracycline Chlamydia trachomatis Bacteria Acyclovir/Ganciclovir Herpes/Cytomegalovirus Virus

As noted above, conjugates of the present invention may also be used for in vitro inhibition of a microorganism, 25 such as in a bioiogical preparation. The term "biological preparation” includes bioiogical samples taken m vivo and in vitro (either with or vvithout subsequent manipulation), as vvell as those prepared synthetically. Representative exam-ples of bioiogical preparations include celis, tissues, Solutions and bodily fluids. such as (or from) blood, urine, saliva, sweat, synovial, cerebrospinal and tears. Briefly, one or more of the conjugates are added to a biological preparation. The precise optimal concentration may vary, depending upon the particular conjugate used. Generally, hovvever, a con-30 centration of about 0.1 to 100 mg per ml will be effective. One of the uses of this aspect of the present invention is to prevent microbial colonization of a biological preparation during rts storage.

The follovving examples are offered by way of illustration and not by way of limitation.

eXAMPĻES 35

Example 1

Preparation of Asialo-GMo-ArrKacicillin 40 A. Preparation of Asialo-GMrOliQosaccharide

Metting points are corrected. Reactions were performed under nitrogen. Concentrations were performed at <40°C (bath). Optical rotations were reconded at 25°C with a Perkin-Elmer 241 polarimeter. Thin-layer chromatography was performed on silica gel 60 F254 (Merck, Darmstadt, FRG) using the follovving eluant systems: A, 4:3:3:2 ethyl acetate: 45 acetic acid: methanol: water, B, 10:5:1 chloroform: methanol: water, C, 113:2 chloroform: methanol: water. The spots were visualized by charring with 5% aqueous sulfuric acid. Silica gel chromatography was performed on Matrex silica Si, 60A, 20-45 MY (Amicon Corporation. Oanvers, Ma. 01923, U.S.A.), using solvent system D, 5:1 methylene chloride: pyridine and E, 10:5:3:1:1 chloroform: methanol: dioxane, vvater: pyridine, Sulfuryl chloride/triflic acid reaģent was made 1 M in toluene containing 10% diethylether. Organic solvents were of p.a. quality and distilled over appropriate šo drying aģents. p-Methylphenyl 3,4,6-tri-0-p-chlorobenzyl-2-deoxy-2-phthalimido-l -thio-p-D-galactopyranoside (1):

Into a stirred solution of p-methylphenyl-2-azido-3,4,6-tri-0-chlorobenzyl-2-deoxy-l-thio-p-D-galactopyranoside 55 (5.00 g) in 1:1 pyridine/triethylamine (200 ml) at room temperature was biiftled H2S until saturation. The flask was sealed and stirring was continued for 2 hours. Then nitrogen was flushed through the solution. and phtalic anhydride (3.0 g) in methylene chloride (100 ml) was added. The mixture was stirred overnight. Then acetic anhydride (50 ml) in toluene (100 ml) was added. After 2 hours. water (50 ml) was added. The organic phase was washed with water. sātu- 6 rated sodium bicarbonate and 1 M sulfuric add and evaporated. The resulting syrup was chromatographed in 7/1 tolu-ene/ethyl acetate. Crystallization of appropriate fractions from diethylether/isooctane gavē pure (1) (3.89 G. 67.5%). mp 63-70°C. (a]0 + 70.1° (c 1.0 ctiloroform).

Ethyl 4-0-p-galactopyranosyl-1-thio-p-D*glucopyranoside (2):

To a mixture of β-lactose peracetate (50 g). ethanethiol (6.9 g. 822 ml) and 203 ml dry CH-CI? was adaed 3C_- E::0 (8.5 g. 7.3 ml) at RT. After 2 hours. TLC (toluene/ethyl acetate 2/3) showed no nore reaction The mixture was sna^en with ca 50C ml 1M NaOH. The organic layer was directly evaporated and taker up in methanoi (750 ml), then NaOMe in methanol (10 ml. 0.5M) was added and the mixture was stirred overnigh: at RT. The TLC (ethyl acetate/acetic acid/methanol/water 12/3/3/3) yields an Rf 0.41. The reaction mixture was neutralized with Dowex (50w x 8. i-Γ). iiltered and concentrated. The residue was recrystallized from ethanol (300 ml). Yield 16 4 g, 56%. mp 191-192°C.

Ethyl 4-0-(4,6-0-benzylidene-p-D-galactopyranosyl)-1 -thio-p-D-glucopyranoside (3): A mixture of (2) (3.00 g) and bensaldehyde (30 ml) was stirred for 1 hour at room temperature. Then formic acid (30 ml) was added, and stirring was maintained for a further 25 minūtes. The clear solution was poured into diethylether (400 ml) during stirring. After 1 hour, the solid was filtered off and dissolved in methanol (50 ml) during heating. After cooling diethylether (25 ml) was added. Crystals were obtained after standing overnight (3.09 g. 84%), 240-242°C. [a]o - 49.3°.

Ethyl 4-0-(4,6-0-benzylidene-2,3-di-0-p-chlorobenzyl-p-D-galactopyranosyl-2.3.6-tri-0-p-chlorobenzyl-l-thio-p-D-giu-copyranoside (4):

Treatment of (3) (2.00 g) with p-chlorobenzyl chloride (3.0 ml) and sodium hydride (1.4 g) in DMF (50 ml) at 0aG under nitrogen gavē a single spot on TLC (toluene/ethyl acetate 4/1, Rf 0.39). Partitioning between toluene and i M sul-furic acid and water, and crystallization from dichloromethane/ethyl acetate/isooctane gavē 3.57 g (4), 77%, mp *75-183°C, [o]Ē + 10.9° (c 1.0, chloroform).

Ethyl 4-0-(6-0-benzyl-2.3-di-0-p-chlorobenzyl-p-D-galactopyranosyl)-2,3.6-tri-0-p-chlorobenzyl-1-thio-p-D-glucopyra-noside (5):

Compound (4) (100 mg) in THF (10 ml) containing molecular sieves 3Ā) 600 mg) at room temperature under nitrogen was treated with NaCNBH3 (100 mg) and HCI (saturated in diethyl ether) as described. After 2 hours. TLC (tolu-ene/ethyl acetate 4/1. Rf 0.55) shovved complete reaction. The mixture was filtered. partitioned between dichloromethane and sodium bicarbonate and water. Pure (5) was obtained after crystallization from ethyl acetate/isooctane (82 mg, 82%). mp 137-139eC. [a]D + 25.6°. 2-(p-Nitrophenyl)ethyl 4-0-(6-0-benzyl-2,3-di-0-p-chlorobenzyl-p-D-galactopyranosyl)-2,3.6-tri-0-p-chlorobenzyl-p-D-glucopyranoside (6): A solution of (5) (500 mg) in methylene chloride (20 ml) was treated with bromine (50 μ) and molecular sieves 4Ā (5.0 b) at 0°C during stirring. After 30 minūtes, TLC (toluene/ethyl acetate 4/1) indicated that no starting matenal remained. and excess bromine was destroyed with two drops of cyclohexene. The slurry was added dropwise to a stirred mixture of 2-(4-nitrophenyl)ethanol (300 mg) and freshly activated zinc chloride (5.0 g) in methylerie chloride (10 ml). while maintaining nitrogen atmosphere and 0°C. After two hours, the mbcture was diluted with methylene chloride, filtered, washed with water and 1 M sulfuric acid, dried and concentrated. The resulting syrup was chromatographed in isooctane/ethyl acetate 1/1. Fractions containing pure material of Rf 0.53 was pooled and concentrated (340 mg. 62%). Nmr analysis showed this to be the desired (6). Crystais of (6) were obtained from diethyl ether/isooctane. mp 11ΟΙ 12°C, [a]c + 22.8°. 2-(p-Nitrophenyl)ethyl 4-0-(3.4,6-tri-0-p-chlorobenzyl-2-deoxy-2-phthalimide-p-D-galactopyranosyl) 1 -0-(6-0-benzyi-2.3-di-0-p-chlorobenzyl-p-D-galactopyranosyl)-2.3.6-tri-0-p-chlorobenzyl-p-D-glucopyranoside (7):

To an ice cooled solution of disaccharide (6) (71 mg. 1 eq) and thioglycoside (1) (58 mg. 1.2 eq) in dry methylene chloride (5.0 ml) containing molecular sieves 4Ā (100 mg) was added S02C^OTf reaģent (0.30 ml. 5 eq) under nitrogen during stirring. The mixture was stirred for 2 hours during which the temperature was allowed to rise to 10°C. Then pyridine (100 μΙ) was added and the mixture was stirred for another hour at room temperature. The mixture was filtered, 7 LV 12233 partrtioned betvveen ethyl acetate and aqueous sodium bicarbonate, dried (MgSOJ and concentrated. After silica gel chromatography in toluene/ethyi acetate 59% of (7) was obtained. 2-(p-Nitrophenyl)ethyl 4-0-(3,4.6-tri-0-p-chlorobenzyl-2-acetamido-2-deoxy-p-D-galactopyranosyl)-4-0-(6-0-benyl· 2,3-di-0-p-chlorobenzyl-p-D-galactopyranosyl)-2,3,6-tri-0-p-chlorobenzyl-p-D-glucopyranoside (8):

To a stirred solution of trisaccharide (7) (400 mg) in toluene/95% ethanol. viC (10 ml) was added hydrazine hydrate (0.3 ml) and acetic acid (0.2 ml). The mixture was refluxed ovemight, coolec. concentrated and co-evaporated with toluene/ethanol. The residue was treated with acetic anhydride/pyridine 1/1 (5 ml) for 30 minūtes at room temper-ature. Concentration, partitioning betvveen toluene and water, drying (MgS04) and concentration gavē a syrup. The syrup was chromatographed on silica gel in n-heptane/ethyl acetate 1/1 (Rf 0.35). Appropriate fractions were pooled and concentrated to give (8) in 52% yield. 2-(p-Trifluoroacetamidophenyl)ethy1 4-0-(2-acetamido-2-deoxy-p-D-galactopyranosyl)-4-0-p-D-galactopyranosyl-p-D-glucopyranoside (9):

To compound (8) (50 mg) in THF (2 ml), acetic acid (1 ml) and water (0.1 ml) was added zinc dust (100 mg) and the mixture was stirred at 0°C under nitrogen. Then a solution of CuS04 x 5 H20 (i 00 mg.ml, 0.2 ml) was added. After 30 minūtes TLC (n-heptane: ethyt acetate 1:1, Rf 0.28) shovved complete reaction. The mixture was filtered, diluted with CH2C12, washed with aqueous sodium bicarbonate, water, dried (MgS04) and concentrated. The residue was dissolved in CH2CI2 (3 ml). The solution was cooled to 20°C and pyridine (40 μΙ) and trifluoroacetic anhydride (20 μΙ) were added. After 10 minūtes TLC (n-heptane: ethyl acetate 1:1, Rf 0.13) shovved complete reaction. The mixture was concentrated to dryness and dissolved in ethyl acetate: ethanol: acetic acid: vvater 4:2:1:1 containing sodium acetate (50 mg) and hydrogenolyzed over Pd/C (10%. 50 mg) at atmospheric pressure for 8 hours as described. Complete debenzylation was indicated by TLC (ethyl acetate/methanol/acetic acid/vvater, 12/3/3/2, Rf 0.15). Purification by C-18 chromatogra-phy as described before gavē 80% of (9). The structures of compounds (1) to (9) are shovvn below.

ClfinO

CH CH

(2) • O) 8

DSnO CffinO

\ .0 C&i

r-l/ I ( C38nO O0nn \ U N-' OSnO' (7)

CSBcC

(8)

CH CH

9 (9) LV 12233 B. Preoaration of Asialo-GMo Oliaosaccharide-Amoxicillin 2-{p-Aminophenyl)ethyl 4-0-(2-acetarmdo-2-deoxy-p-D-galactopyranosyl)-4-0-p-D-galactopyranosyl-p-D-glucopyran-oside(1Q): 100 mg of compound (9) is dissolved in 10 ml 25% ammonia at 50°C. The mixture was left for an hour and is then put directly on a C 18 column and washed with water until the pH reaches about S The column was then eluted with 30% methanol. Ninhydrin positive fraotons were pooled and partly evaporated to remove the bulk of methanol The remaining solution was subjected to freeze-drying which gavē a white fluffy povvder pure by TLC. The yield is 95%. 2-(p-iso-Thiocyanatophenyl)ethyl 4-0-(2-acetamido-2-deoxy-p-D-galactopyranosyt)-4-0-p-D-galactopyranosyi-p-D-glucopyranoside (11): 100 mg of compound (10) is dissolved in 10 ml 70% ethanoi at room temperature. To the solution is added a hvofold excess of thiophosgen and the solution is stirred for five minūtes. After that enough ion exchanger is added to rise the pH to about 5 (Dowex 1 x 2 OH form). The ion exchange is then filtered off and vvashed with water. The filtrate is evaporated to remove most of the ethanoi. The remaining solution is then freeze-dried to dryness which leaves a white pow-der essentially pure by TLC and NMR. The yield is about 50%. 2-(p-Amoxicillin thiourea phenyl) ethyl 4-0-{2-acetamido-2-deoxy-p-D-galactopyranosyl)-4-0-p-D-galactopyranosyl-p-D-glucopyranoside (12): 50 mg of compound (11) is dissolved in 5 ml DMF. An equimolar amount of Amoxicillin is added and the solution is left for two days at room temperature vvhich gives a clear yellow solution. On TLC (EtOAc:MeOH:H2O.HOAc 12:3:3:2) only traces of the reactants can be seen and one major product together with small amounts of byproducts. The solvent is evaporated with the help of a vacuum pump slightly above room temperature. The remaining solid is dissolved in water and chromatographed on a C 18 column. It is first eluted with water and thereafter with 30% methanol. The desired fractions are pooled and freeze-dried after evaporation of the methanol. The structure of the substance is con-firmed by NMR and FAB/MS. The yield is 62%. The structures of compounds (9) to (12) are shown below. 10

(9)

ΝΗ,

NCS (η) 11 LV 12233

20

Exampte 2

Preparation of Asialo-GM1-AmQxieillin 25 A. Asialo-GM.

Asialo-GM., can be purified from gangliosides as described above or purchased (BioCarb Chemicals, Lund, Swe-den), 30 B. Preparation of Asialo-GM,-Amoxidllin Usina A Hetero-Bifunctional Reaģent

Asialo-GM, (BioCarb Chemicals, cat. # 65/03) and other relevant glycolipids are made to a concentration of 10 mg/ml in HPLC-grade dimethylsulfoxide (DMSO) and stored at 4°C until use. The photo-heterobifunctional reaģent ANB-NOS (Pierce, cat. # 21551) is dissolved in the dark in HPLC-grade DMSO at a concentration of 300 mg/ml and 35 stored in the dark at 4°C until use. Amoxicillin (Sigma. cat. # A-8523, lot # 29F0730) is dissolved in DMSO to a concentration of 120 mg/ml. In the dark. ANB-NOS-DMSO and Amoxicillin-DMSO are mixed in a 1:1 ratio (wt/wt) and incu-bated at room temperature tor one hour (step 1 in Figurē 2). After this incubation in the dark, asialo-GM·, is added to the reaction mixture in a ratio of 12:1 ANB-NOS-Amoxicillin to asialo-GM,. The reactīon mixture is exposed to a sun-lamp (G.E. bulb # RSM-6) for 15 minūtes where the reaction mixture will change from yellow to amber resulting in 40 Amoxicillin-Asialo-GM, (step 2 in Rgure 2). The reaction is appraximately 30%-50% efficient.

Example 3

Preparation of Liposomes Containino Microoraanism Receotor and Encaosulatina Antimicrobial Aoents 45

Receptor liposomes were prepared based on the methodologies described in Gruner et al. fBiochemistrv 24:2833-2842,1985) and Dahlgren et al. fJ. Immunol. Meth. 44:223-234.1981). In brief. liposomes were prepared acconding to the procedure of Gruner et al. using a ratio of cholesterol/phosphatidyicholine/sphingolipid (1:1:1. molar ratio) as described by Dahlgren et al. When glycolipids and gfycolipid receptors were used. sphingolipid was reduced by the cor-so responding amount of glycolipids used. Drug(s) were added in excess prior to liposome formation.

Lipids and glycolipids (90 mg cholesterol, Matreya; 180 mg phosphatidyfchoiine, Sigma: 90 mg sphingomyelin, Sigma; 45 mg asialo-GM,. BioCarb Chemicals: 45 phosphatidylethanolamine. Sigma) were dissolved in 100 ml of chlo-roform in a round-bottom flask and rotoevaporated. The resulting film was dissolved in 50 ml of diethyiether. Aqueous drug(s) were added in Hepes buffer (e.g., bismuth subsalicylate. Crescent Chem. Co., at 25 mg/ml in buffer containing 55 72.5 mM NaCI, 72.5 mM KC1 and 10 mM Hepes, pH 7.4). The remaining 250 ml of diethylether was added. While son- icating in a vvater bath maintained at room temperature or lovver. the ether was removed by a stream of N2. Ether removal was discontinued when about 99% of the ether is gone and the volume remaining is equal or less than the vol-ume of the agueous phase added. Liposome formation was complete at this stage as evidenced by the appearance of 12 a white waxy "cake" in the buffer.

The liposome material and buffer were transferred to giass tubes and centrifuged at room temperature for 20 min. at 12,000 RPM (SA-600 rotor). The liposome peliet was washed three times with the Hepes buffer (50-100 ml per wash). After the final wash, the liposomes were resuspended in Hepes buffer (e.g., so that each dose wi!l be 100 μΙ per 5 dose). Alternatively, the liposomes may be resuspended in a concentrated amount of bismuth (25 mg/ml) for a final concentration of 20 mg/ml. txample 4 κ Inhibition of Streptococcus oneurnaniae bv Asiaio-GM1-Amoxicillin m Vitro

Determination of the minimum inhibitory concentration (MIC) was done according to recommendations published by the National Committee for Clinical Laboratory Standards (Tentative Standard NCCLS Publication M7-T2, Villanova, Pa., NCCLS, 1988). Both amoxicillin and amoxicillin-asialo-GM1 (prepared according to Example 2) were tested for T5 bacteriostatic and bacteriocidal Ievels using a clinical isolate of Streptococcus pneumoniae. Stock Solutions of amoxi-cillin and amoxicillin-asialo-GM1 were diluted to 10 pg/ml in Trypticase soy broth without glucose (T-soy from Difco). Serial two-fold dilutions were made from stocks in a series of 16 tubes each containing 1 ml of medium such that tube 1 contained 5 pg/ml through tube 16 which contained 0.0001 pg/ml of antibiotic. To each of these tubes was added 0.05 ml of a suspension of S. pneumoniae (approximately 1.5 χ 108) organisms/ml using a 0.5 McFarland Standard. T-soy 2c broth with no organisms and with organisms and no antibiotics served as negative and positive Controls, respectively. Ali tubes were incubated at 37aC in 5% C02/95% air for 18 hours and read for turbidity and MIC. For determination of bacteriocidal Ievels (MBC), 0.00i ml was taken from each tube shovving no visible grovvth, inoculated onto 5% sheep blood agar plates and incubated an additional 18 hours. A 99% reduction in colony count compared to control tubes was considered bacteriocidal (MBC). The results of the comparison of amoxiciilin and amoxicillin-asialo-GM1 are shown 25 in Table 2.

Table 2 Comparison of amoxicillin and amoxiciilin-asialo-GfM 1 against Streptococcus pneumoniae as measured by minimum inhibitory concentration (MIC) and minimum bacteriocidal concentration (MBC). Drug MIC (Ig/ml) MBC (Ig/ml) Amoxicillin 0.04 0.04 Amoricillin-Asialo-GM-ļ' 0.005 0.005 'Prepared using an ANB-NOS-Amoxicillin to gtycolipid ratio of 1:1

3C 35 4C Example 5

Inhibition of Camnvlobacter < He‘icobacter) ovlori In Vivo

Clinical studies suggest that Helicobacter Pylori-Uke Organisms (HPLO) may cause duodenal ulcers, gastritis and 45 hypochlorhydria. Moreover. HPLO may be responsible for unexplained vomiting in man. Several studies in Rhesus mon-keys have demonstrated the presence of organisms closely resembling HPLO found in humāns. In the monkeys used in this experiment, small curved rod-shaped bacteria measuring 3-4 μm long and 0.5-10.0 μηι wide were seen in dose proximity to the mucosal epithelial celis in 8/29 monkeys. These bacteria were very similar to C. py>ori observed in humāns and were therefore called HPLO. The effect of these bacteria on radiation induced vomiting and gastric sup-5c pression is unknown.

It is irrteresting that. although gastritis is knovvn to be associated with gastric ulcer, duodenal ulcers and gastric can-cer, its treatment remains symptomatic. and little if any improvements is observed after administration of typical antac-ids and/or histamine H- antagonists. In contrast, administration of bismuth salts and of several antibiotics has improved gastritis. vvhile eradicating HPLOs. However. the prolonged use of large doses of antibiotics may lead to eradication of 55 the normai flora and to the devefopment of bacterial resistance and recurrence of infection is extremely freguent. 13 LV 12233 A. Trearment with Asialo-GM, -Amoxicillin

Two domestic born male rtiesus monkeys, Macaca Mulatta, in vvhich HPLO is present in gastric biopsies and weighing 3-7 kg, were housed in individual stainiess Steel cages in conventional hoking rooms of an AALAC accredited 5 animal facility. The two infected monkeys were treated by administering blindly and t.i.d. either placebo or 7 mg/kg of asialo-GMramoxicillin (prepared according to Example 2) diluted in Tang. a drink that is avidly consumed by monkeys and allows reliable oral administration of medications. The animals were treated for tvvo days oniy, but HPLO were cul-tured only from gastric biopsies obtainsd immediately after the end of the treatment in the animal receiving placebo and not in the one treated with the recepto· conjugate. B. Treatment With ūoosomes Containmo Microoroanism Receptor and Encaosulatino Antimicrobial Aģents

Liposomes containing a specific glycolipid receptor for Helicobacterpylori (HP) and encapsulating amoxicillin, met-ronidazole and bismuth subsalicylate (7, 7, and 10 mg/kg, respectively) were prepared according to Example 3. In vitro, is these liposomes inhibited the growth of HP in broth by a factor of 4 to 10 as compared with free antimicrobial aģents alone. Gastroduodenoscopies and mucosal biopsies vvere performed under anesthesia in six colony-bred rhesus mon-keys spontaneously infected with HP-LJke Organisms (HPLO). The animals were then treated orally for five days with the liposome complex and the endoscopies were repeated 4, 17 and 60 days later. Mucosal biopsies vvere grown on HP medium, tested for urease activity, or fixed for light microscopy, and the presence or absence of infection was 20 assessed blindly. At each time, plasma IgG Ievels (as a percentage of the mean plus 3 Standard deviations of 40 non-infected children) were determined against a pool of H. pylori antigens in an assay with >95% sensitivity and specificity for human infection. Within one week after the end of treatment, infection in the corpus, but not in the antrum, was decreased or suppressed, and plasma IgG did not change significantly (0.85 ± 0.14 vs. 0.69 ± 0.09; NS).

From the foregoing, it will be evident that, although specific embodiments of the invention have been described 25 herein for purposes of illustration, various modifications may be made vvithout deviating from the and scope of the invention.

Claims 30 1. A microorganism receptor-agent conjugate, comprising at least one aģent coupled to at least one glycolipid, said glycolipid being capable of seiectively binding a bacterial microorganism. 2. The microorganism receptor-agerrt conjugate of Claim 1, vvherein said glycolipid is asialo-GM-,. 35 3. The microorganism receptor-agent conjugate of Claim 16, vvherein said glycolipid is asialo-GM2. 4. The microorganism receptor-agent conjugate of Claim 1, 2 or 3, vvherein said aģent is an antibiotic. 5. The microorganism receptor-agent conjugate of Claim 4, vvherein said antibiotic is a penicillin. 40 6. The microorganism receptor-agent conjugate of Claim 4, vvherein said penicillin is amoxicillin. 7. The microorganism receptor-agent conjugate of any one of the preceding claims, vvherein said conjugate com-prises a carrier coupled to at least one glycolipid capable of selectively binding a bacterial microorganism, and said 45 carrier bears at least one aģent. 8. The microorganism receptor-agent conjugate of Claim 7, vvherein said aģent is an antibiotic. 9. A microorganism receptor-agent conjugate of any one of Claims 1 to 8 for use as a therapeutic aģent. 56 10. A microorganism receptor-agent conjugate of any one of Claims 1 to 8 for use for the treatment of an infection due to a pathogenic bacterial microorganism. 11. Use of the microorganism receptor-agent conjugate of any one of Claims 1 to 8 for the manufacture of a medica-55 ment for the treatment of a bacteriai infection. 12. Use according to Claim 11, in which said aģent is an antibiotic. 14 13. Use according to Claim 12, in which said antibiotic is amondilin and said bacteriai irrfection is by Streptococcus pneumoniae. 14. Use according to Claim 12, in which said antibiotic is amoxicillin and said bacteriai irrfection is by Campylobacter pylori or Helicobacter pyiori. 15. A method for inhibiting a bacteriai microorganism in an in vitro biological preparation, comprising contacting said in vrjo biological preparation with an effective amount ot the microorganism receptor-agent conjugate of any one of Claims 1 to 8. 16. The method according to Claim 15. in which said aģent is an antibiotic. 17. The method according to Claim 16, in which said antibiotic is amoxicillin and said bacteriai infection is by Streptococcus pneumoniae. 18. The method according to Claim 16, in which said antibiotic is amoxicillin and said bacteriai irrfection is by Campy-lobacter pylori or Helicobacter oylori. LV 12233 FIG.1

FLOVVCHART RECEPTOR DRUG SYNTHESIS

BIOMATERIAL

ISO LATI OS

GLYCOCONJUGATE

:M0N0)SACCHARIDES SYNTHESIS OLIGOSAC :CHARJCDE

ETTHER (ijetker)

SYNTHESIS

V

18 LV 12233

PHOTOREACTIVE LINKER

LINKER-DR’JG ASIALO-GM1

ASIALO-GM^ LINKER-AMOXICILLIN ACTIVE RECEPTOR DRUG 19

Claims (18)

1. A conjugate of a microorganism receptor-agent comprising at least one agent linked to at least one glycolipid, wherein said glycolipid is capable of selectively coupling to bacterial microorganisms. 2. The microorganism receptor-agent conjugated according to claim 1, wherein said glycolipid is azialo-GM. 3. The microorganism receptor-agent conjugate of claim 1, wherein said glycolipid is azialo-GM2. 4. The microorganism receptor-agent conjugated according to claim 1, 2 or 3, wherein said agent is an antibiotic. 5. The microorganism receptor-agent conjugated according to claim 4, wherein the antibiotic is penicillin. 6. The microorganism receptor-agent conjugated according to claim 4, wherein said penicillin is amoxicillin. The microorganism receptor-agent conjugate according to any one of the preceding claims, characterized in that the conjugate comprises a carrier coupled to at least one glycolipid capable of selectively coupling to bacterial microorganisms and containing at least one agent. 8. The microorganism receptor-agent conjugate of claim 7, wherein said agent is an antibiotic. 9. The microorganism receptor-agent conjugated according to one of claims 1 to 8. used as a therapeutic agent. 10. The microorganism receptor-agent conjugated according to one of claims 1 to 8. used to treat infection caused by a pathogenic bacterial microorganism. A conjugate of a microorganism receptor-agent according to one of claims 1 to 8. for use in the preparation of a medicament for treating a bacterial infection. 12. The method of claim 11, wherein said agent is an antibiotic. 13. The method of claim 12, wherein said antibiotic is amoxicillin and is caused by Streptococcuspneumoniae. Use according to claim 12, characterized in that the antibiotic is amoxicillin and this bacterial infection is caused by Campyiobacterpyiorivai Helicobacter py / ori. A method for inhibiting a bacterial microorganism in an in vitro biological preparation comprising the in vitro interaction of this biological preparation with a microorganism receptor-agent conjugate according to any one of claims 1 to 8. points. 16. The method of claim 15, wherein said agent is an antibiotic. 17. The method of claim 16, wherein said antibiotic is amoxicillin and is caused by Streptococcus pneumoniae. 18. The method of claim 16, wherein said antibiotic is amoxicillin and said bacterial infection is caused by Campyiobacterpyiorivai Helicobacter pyiori.