METHOD OF USING LECTINS FOR PREVENTION AND TREATMENT OF SKIN DISEASES AND DISORDERS

Diseases and disorders of dermal tissue such as the skin, hair and nails are treated or prevented by administering one or more lectins, capable of binding to the surface of pathogenic microorganisms inhabiting the hair, skin, and nails, or of binding to the superficial tissues that comprise hair, skin, and nails. The lectins may be administered topically or subcutaneously to a patient infected with pathogenic microorganisms or in danger of being exposed to such pathogens. Lectins that stimulate cell mitosis may also be administered to accelerate wound healing and restore the appearance of age-wrinkled skin. Lectins that coagulate blood can be administered to assist in stopping bleeding from skin lesions. The lectins may be applied to the skin in a pharmceutically acceptable vehicle.

DETAILED DESCRIPTION OF THE INVENTION AND PREFERRED EMBODIMENTS Lectins are carbohydrate-binding proteins of non-immune origin that agglutinate cells or precipitate polysaccharides or glycoconjugates, i.e., proteins or lipids conjugated to oligo- or polysaccharides. They are widely distributed and have been isolated from both plant and animal sources. Their reactions with living cells are based on their ability to bind with antibody-like specificity to particular arrangements of the sugar residues that make up oligo- or polysaccharides. The surfaces of eucaryotic cells contain numerous molecules of glycoproteins and glycolipids. Such glycoconjugates are found in the plasma membranes of cells of multicellular animals, including mammals and humans, as well as on the surfaces of single-celled eucaryotic organisms. Similarly, the cell walls and capsules of bacteria and the envelopes of viruses contain structural polysaccharides and/or glycoproteins. The carbohydrate moieties of these molecules which are displayed on the cell surfaces exhibit great variety in composition and structure that serves to distinguish the types of cells and to serve as a signal to other cells or materials which come into contact with the cell. For, example, variation in the carbohydrate moieties of glycoproteins and glycolipids in the plasma membrane of red blood cells serves as the basis for conventional blood typing. When lectins recognize and bind to certain carbohydrate moieties, they may serve to cross-link and agglutinate the cells bearing the binding groups, a property that earns for them the alternate name of agglutinins. Furthermore, because the same sort of carbohydrate moieties often serve as attachment points for pathogens to bind to target cells and invade them, lectins may block infection of target cells by blocking the sites used by pathogens as recognition markers. The same type of specific binding occurs between sperm and egg in conception, and can be blocked by lectins. The binding ability of lectins may be very specific for certain mono- or oligosaccharides, allowing lectins to be used as a powerful tool for investigating the oligosaccharide epitopes on the surface of organisms or cells. Lectins can distinguish between blood cells of specific blood type, malignant from normal cells, and among species and genera of organisms. While glycoproteins, glycolipids, and bacterial cell walls and capsules are believed to be the main lectin-binding locations on the surfaces of cells, it is not excluded that carbohydrate moieties derived from other molecules or cellular structures may be displayed on the cell surface or that other lectin-binding structures may be targets for the lectins used in the method of this invention. Current medical uses of lectins include distinguishing erythrocytes of different blood types (blood typing). More recently, lectins have been used ex vivo in depleting T-cells of patients undergoing bone marrow transplantation. Among the microorganisms that are bound by certain lectins are infectious organisms such as bacteria, protozoa, fungi, and viruses. Lectins may be used to identify such microorganisms in vitro and are also capable of binding to them in vivo, thereby preventing them from infecting living cells. Human disease-causing organisms that can be bound by lectins include the organisms responsible for numerous sexually transmitted diseases (as described in copending U.S. application Ser. No. 08/317,599) and diseases of the oral and alimentary canal (as described in copending U.S. application Ser. No. 08/385,306), as well as Propionibacterium acnes, Propionibacterium granulosum, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes, Corynebacterium minutissimum, Erysipelothrix rhusiopathiae, various species of Proteus, Propionibacterium E avidum, Trichophyton rubrum, Microsporum canis, Trichophyton verrucosum, Trichophyton tonsurans, Trichopllyton mentagrophytes, Epidermophyton floccosum, Candida albicans, Malassezia furfur, Malassezia orbiculare, Exophiala ( Phaeoanellomyces ) werneckii, Trichosporon beigelii, Piedraia hortae, papovaviruses, human papilloma viruses, HSV-1, HSV-2, varicella-zosrer virus, Treponema pallidum, the virus causing rubella, the virus causing rubeola, and others. Other infections and diseases in which the portal of entry or initial attachment is the skin, hair, or nails are also capable of being treated or prevented by administration of lectins according to this invention. According to the invention, a dose of lectins effective for binding and agglutinating pathogenic microorganisms and/or blocking the recognition sites on target cells is administered to the skin, hair, or nails prophylactically or as therapy. Because of the specificity of lectins for certain microorganisms, a mixture of lectins can be chosen for their ability to bind or agglutinate specific pathogens. Lectins also have mitogenic activity and can induce quiescent cells to grow and multiply. For example, lectins can stimulate mitosis in lymphocytes. It is suspected that most lectins of vegetable origin have this ability. According to the invention, a dose of one or more lectins sufficient to induce cell mitosis in skin can be administered in areas of age-wrinkled skin so as to mitigate or eliminate the wrinkling. Alternatively, a dose of one or more lectins sufficient to induce cell mitosis in skin can be administered so as to promote wound healing. Many lectins also have the ability to agglutinate (coagulate) blood because of their ability to bind to both erythrocytes and leukocytes. According to the invention, a dose of one or more lectins sufficient to coagulate blood can be administered to the area of a skin laceration or to open, surgical incisions in order to stanch bleeding. A representative listing of lectins, the abbreviations by which they are referred to, and their sources are given in Table 1. 1 TABLE 1 Representative Lectins, Abbreviations & Sources AAP Aaptos papillata (sponge) AAnA Anguilla anguilla (eel serum) AAurA Aleuria aurantia (orange peel fungus) ABA Agaricus bisporus (common mushroom) ABrA Amphicarpaea bracteata (hog-peanut) AGT Agardhiella tenera (red alga) AL Hippeastrum hybrid (amaryllis bulb) APA Abrus precatorius (Jequirity bean) AS Avena sativa (oat) BDA Bryonia dioica (white bryony) BPA Bauhinia purpurea alba (camel s foot tree) CA Colchicum autumnale (meadow saffron) CAA Caragana arborescens (Siberian pea tree) CCA Cancer antennarius (California or blue crab) ConA Canavalia ensiformis (jack bean) CPA Cicer arietinum (chickpea) CSA Cytisus scoparius (Scotch broom) DBA Dolichos biflorus (horse gram) DSA Datura stramonium (jimsonweed, thorn apple) ECA Erythrina cristagalli (coral tree) ECorA Erythrina corrallodendrin (coral tree) EEA Evonymus europaeus (spindle tree) GNA Galanthus nivalis (snowdrop bulb) GSA-I/GSA-II Griffonia simplicifolia (African legume) HAA Helix aspersa (garden snail) HPA Helix pomatia (Roman or edible snail) JAC (Jacalin) Atocarpus integrifolia (jackfruit) LAA Laburnum alpinum (golden chain) LBA Phaseolus lunatus (also limensis ) (lima bean) LCA (LcH) Lens culinaris (lentil) LEA Lycopersicon esculentum (tomato) LFA Limax flavus (garden slug) LIP (Limulin) Limulus polyphemus (horseshoe crab) LOA Lathyrus odoratus (sweet pea) LTA (LOTUS) Lotus tetragonolobus (asparagus pea) MAA Maackla amurensis (maackla) MIH Mangifera indica (mango) MPA Maclura pomifera (Osage orange) NPL (NPA) Narcissus pseudonarcissus (daffodil) PAA Persea americana (avocado) PHA (PHA-L) Phaseolus vulgaris (red kidney bean) PNA Arachis hypogaea (peanut) PSA Pisum sativum (pea) PTP Ptilota plumosa (red alga) PWA Phytolacca americana (pokeweed) PTAgalactose Psophocarpus tetragonolobus (winged bean) PTAgalNac Psophocarpus tetragonolobus (winged bean) RCA-I/RCA-II Ricinus communis (castor bean) RPA Robinia pseudoacacia (black locust) SBA Glycine max (soybean) SJA Sophora japonica (Japanese pagoda tree) SNA Sambucus nigra (elderberry) SOF Soduim fragile (green alga) STA Solanum tuberosum (potato) TKA Trichosanthes kirilowii (China gourd) TL Tulipa gesneriana (tulip) TMT Tomentine (seaweed Codium tomentosum ) UEA-I/UEA-II Ulex europaeus (gorse or furze seeds) VAA Viscum album (European mistletoe) VFA Vicia faba (fava bean) VGA Vicia graminea (herb) VRA Vigna radiata (mung bean) VSA Vicia sativa (vetch) VVA Vicia villosa (hairy vetch) WFA Wisteria floribunda (Japanese wisteria) WGA Triticum vulgaris (wheat germ) suc-WGA Succinylated WGA The choice of lectins for prophylaxis or treatment of a particular infection is determined, in part, by the lectin-binding properties of the pathogenic microorganism, which is a function of the composition of the particular oligosaccharide residues of the glycoproteins and glycolipids found on the external surface of the pathogen. For example, Staphylococcus aureus can be bound by the lectins WGA (Davidson, S K et al, J Clin Microbiol 15:547-53 (1982)), ConA (Reeder, N J et al, J Immunol 196:334-40 (1971)), and LIP (Gilbride K J et al, Prog Clin Biol Res 29:525-35 (1979)). WGA and ConA have a binding affinity for N-acetyl-D-glucosamine residues expressed on a surface (Doyle, R J, Lectin-Microorganism Interactions, Marcel-Dekker (New York), 43-55 (1994)), and strains of S. aureus are known to express such residues (Slifkin, M, Lectin-Microorganism Interactions, Marcel-Dekker (New York), 144-5 (1994)). Candida albicans can be bound by the lectins ConA, LCA, and GSA-II (Dean, J W et al, J Biol Chem, 265: 12553-62 (1990). Each of these lectins has binding specificity for N-acetyl-D-glucosaminyl residues (Doyle, ibid.). These carbohydrate moieties have, in turn, been shown relevant for the binding of C. albicans (Ghannoum, M A et al, Candida albicans: cellular and molecular biology, Springer-Verlag (Heidelberg), 144-163 (1991)). Herpes simplex viruses can be bound by the lectin HPA (Slifkin, M et al, J Clin Microbiol 27:1036-39 (1989)). HPA can bind to residues of N-acetyl-D-galactosamine (Doyle, ibid.). N-acetyl-D-galactosamines represent a major class of oligosaccharide chains in viral envelope proteins. Alternatively, a lectin can be selected for its ability to bind appropriately to a dermal tissue, thereby blocking the potential binding sites for pathogens; this technique has applicability for both prophylaxis and therapy. The choice of lectins for stimulating mitosis for the purpose of mitigating age-induced wrinkles or promoting the healing of wounds, including burns, is determined by the tissue-binding properties of the lectin. Examples of mitogenic lectins include PHA (Nowell, PC, Cancer Res 20:462-66 (1960)), SBA (Licastro, F et al, Lectins, Vol. III, Walter de Gruyter & Co. (Berlin), 293-302 (1983)), and TL (Kilpatrick, D C et al, Lectins-Biology, Biochemistry, Clinical Biochemistry, Vol. 7, sigma Chemical Co. (St. Louis), 259-63 (1990)). Many lectins are capable of agglutinating blood and are, therefore, useful for stopping the bleeding from superficial wounds and open surgical incisions by local, e.g., topical, administration to a bleeding lesion. ConA, WGA, and LCA are examples of lectins capable of agglutinating all types of human blood. While the lectins discussed above and the organisms and conditions against which they are effective are representative of useful lectins according to the invention, it is to be understood that other lectins may be discovered which are also useful for these purposes. The administration of lectins for these various dermal diseases and disorders will depend upon the particular condition and whether prophylaxis or therapy is required. In certain instances, a mixture of lectins is preferred. For example, a prophylactic product designed to protect against a variety of dermal diseases would contain a mixture of lectins selected for their ability to bind to certain dermal receptors and/or individual pathogens. In some cases, a single lectin will suffice. As an example involving prophylaxis, when Treponema pallidum is transmitted to the superficial penile tissues as a result of intercourse, it can be neutralized by the prompt administration of a lectin, thereby preventing development of syphilis. The lectin SBA binds to Treponema pallidum (Fitzgerald, T J et al, Infect Immun 24:261-68 (1979)) and is useful for this application. In this case, the lectin product is applied either immediately before or after intercourse. If, instead of binding directly to Treponema pallidum, the lectin is chosen so as to bind to the penile receptors sought by the pathogen, then the lectin is preferably administered prior to intercourse. For acne and other conditions, a single lectin product (containing one or more lectins) will frequently be useful for both prophylaxis and therapy. In many cases, the course of administration will begin with a therapeutic dosage because the condition is already well-developed. Upon resolution of the condition, a maintenance dosage will be employed for prophylactic purposes. Sometimes, the therapeutic and prophylactic dosages will be equivalent. Certain therapeutic regimens of the invention, in order to satisfactorily resolve a particular condition, will require the initial administration of one lectin product followed by another, different lectin product. The lectins may be administered in a variety of forms for delivery to dermal surfaces, either topically or subcutaneously. Topical vehicles include creams, ointments, sprays, lotions, gels, solutions, foams, soap and non-soap bars, shampoos, rinses, and powders. Some of these forms may also be pre-impregnated into gauze or other sorptive coverings intended to be applied to the skin. Vehicles may be either aqueous or non-aqueous. Some vehicles may contain agents, e.g., natural or synthetic polymers, which form a dry, occlusive film when applied to the skin. Such polymers might include cellulose derivatives such as sodium carboxymethyl cellulose, methylcellulose, 2-hydroxyethyl cellulose; poly(vinylpyrrolidone); poly(acrylic acid) and salts thereof; and the like, as are known to those skilled in the art. Such films may have controlled delivery properties in order to provide a sustained delivery of lectin to the target organism or dermal receptor. Other vehicles, for either controlled or bolus delivery of lectins, will be apparent to one of ordinary skill in the art. The concentration or proportion of the lectin active ingredient in the dosage forms used in the method of the invention will vary widely depending on the particular application. It is even possible to use the lectins in neat form, i.e., as pure solids without admixture of any vehicle, e.g., as a dusting powder of finely divided lectins applied to the skin. When the lectins are applied in a vehicle or excipient, the concentration will be determined by the amount of lectin to be applied to the dermal tissues, among other factors. If a high concentration of lectins on the dermal tissues is required a dosage form such as a lotion, ointment, or the like having a high concentration of lectins, e.g., greater than 50% by weight may be used. If a lesser concentration of lectins on the dermal tissues is sufficient to achieve the therapeutic or prophylactic goal, a less concentrated formulation, e.g., less than 50% by weight can be used. It is also according to the invention to apply the lectins dispersed in a fugitive vehicle, e.g., a vehicle that is absorbed into the skin or a volatile vehicle such as water or a pharmaceutically acceptable volatile alcohol, which serves to disperse the lectins over the surface of the tissues to be treated and then evaporates or is absorbed by the skin to leave a coating of lectins on the surface of the tissues. Lectins dispersed in such a vehicle may be applied to the skin by manual distribution or by spraying and allowed to remain on the surface until the fugitive vehicle has disappeared leaving a deposit of lectins on the skin surface. Such vehicles may merely deposit the solid lectins on the skin surface or may also contain non-volatile ingredients that can serve to hold the lectins in place on the tissues after the fugitive vehicle has departed. Duration and amount of dosage will be determined by the type and severity of condition, including the number of pathogens to be neutralized, and whether prophylaxis or therapy is intended. Dosage is also dependent upon the strength of binding between the lectin and the pathogen receptor or dermal receptor, on the binding constant for the interaction between the lectin and the receptors, and on the number of receptors that have to be saturated with lectin in order to produce an effective response. Dosage will also be affected by the bioavailability of the lectin to interact with the receptors. Accordingly, while the practitioner can gain some guidance as to an effective dose from the experimental determination of the binding effectiveness of a given lectin for a particular dermal condition, it must be expected that determination of an effective dose will involve some experimentation of the type that is entirely conventional in the development of pharmaceutical treatment for the skin diseases and disorders which are the subject of this disclosure. 
 EXAMPLE This example illustrates the binding of various lectins to Propionibacterium acnes, which is a principal organism involved in the development of lesions associated with acne vulgaris. P. acnes (ATCC 6919) was grown under anaerobic conditions at 37° C. for 3-4 days on blood agar plates containing 5% sheep blood. The bacteria were harvested with 0.01 M sodium phosphate buffer (pH 7.2) containing 0.15 M NaCl (PBS), washed twice with PBS, and suspended to a final optical density of 0.9 in sodium bicarbonate buffer, pH 9.5. Bacteria (100 mL) were added to flat-bottomed wells of polystyrene microtiter plates (Corning) and incubated at room temperature overnight. The coated plates were then washed three times with Hanks balanced salt solution supplemented with HEPES buffer containing 0.1% (v/v) Tween 20 (HBSST), pH 7.2, followed by the addition of 15 &mgr;g (150 &mgr;g/mL HBSST) of the appropriate biotinylated lectin. After two hours at ambient temperature, the wells were emptied and washed three times with HBSST. Bound biotinylated lectin was detected by the addition of 100 ng of streptavidin alkaline phosphatase (10 ng/&mgr;L), followed after one hour by washing the cells as above, followed by the addition of 100 &mgr;g of p-nitrophenol phosphate (1 mg/mL). Color production was quantified using a spectrophotometer at 405 nm. Lectins were evaluated for their possible reactivity with immobilized P. acnes in vitro. The lectins LcH, STA, ConA, PSA, VFA, and MPA showed markedly strong binding to P. acnes, producing optical densities that were greater than 3.00. The lectins GNA, CPA, NPA, LEA, Jacalin, UEA, and BPA showed strong binding, while CAA, LAA, SBA, WFA, RPA, and LBA bound moderately with P. acnes in vitro. Other lectins reacted weakly with these bacteria. The experimental data are summarized in Table 2 below. 2 TABLE 2 Lectin Optical Density LcH >3.00 STA >3.00 ConA >3.00 PSA >3.00 VFA >3.00 MPA >3.00 GNA 2.16 CPA 1.65 NPA 1.42 LEA 1.32 Jacalin 1.20 UEA 1.15 BPA 1.12 CAA 0.91 LAA 0.87 SBA 0.76 WFA 0.70 RPA 0.63 LBA 0.54 VVA 0.45 DSA 0.43 PHA 0.43 CSA 0.42 Lotus 0.41 ECA 0.40 HAA 0.40 PNA 0.38 ABA 0.32 MAA 0.31 WGA 0.31 SJA 0.27 suc-WGA 0.26 TKA 0.26 The invention having now been described, it should be understood that it may be embodied in other specific forms or variations without departing from its spirit or essential characteristics. Accordingly, the embodiments described above are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.