A proline-rich polypeptide (PRP) with immunoregulatory properties isolated from ovine colostrum. Murine thymocytes have on their surface a receptor specific for PRP.
A proline-rich polypeptide (PRP) was isolated from ovine colostrum. The polypeptide exhibits immunoregulatory properties. It induces maturation of murine thymocytes into functionally mature helper or suppressor T cells. To elucidate the mechanism of interaction of the polypeptide with thymocytes, effect of PRP immobilized on insoluble carriers on thymocytes was compared with the effect of soluble PRP. It was found that PRP covalently linked to cellulose discs or AffiGel 702 or adsorbed on polystyrene latex beads shows activity similar to activity of PRP in solution. A contact of PRP with the cell surface is satisfactory to induce maturation of thymocytes. PRP adsorbed on polystyrene latex beads forms rosettes with thymocytes. Formation of rosettes is specifically inhibited by soluble PRP. The results obtained suggest that murine thymocytes have on their surface a receptor specific for PRP.
D000818:Animals; D003126:Colostrum / Q000032:analysis* / Q000276:immunology; D005260:Female; D051379:Mice; D010455:Peptides / Q000276:immunology / Q000302:isolation & purification*; D011247:Pregnancy; D055232:Proline-Rich Protein Domains; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018000:Receptors, Peptide; D012397:Rosette Formation; D012756:Sheep; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism*
D010455:Peptides; D011956:Receptors, Cell Surface; D018000:Receptors, Peptide; C051035:proline-rich polypeptide receptor