title: Lymphocyte major histocompatibility complex-encoded class II structures may act as sperm receptors.
abstract: Human sperm and blood cells were cocultured in vitro to determine whether specific interactions occur between gametes and blood cells. Evidence for cell type-specific sperm binding and penetration of lymphocytes is presented together with findings that suggest that either or both events involve major histocompatibility complex-encoded class II molecules on lymphocytes and a sperm ligand that is immunoreactive with antibodies to T-cell surface antigen T4. Involvement of HLA-DR is suggested by the pattern of sperm interactions with HLA-DR-positive and -negative cells and by inhibition of sperm binding to HLA-DR-positive cells by a monoclonal antibody that identifies a nonpolymorphic determinant on the HLA-DR molecule. That the complementary sperm ligand may be a T4-like structure is suggested by specific inhibition of sperm-lymphocyte binding with monoclonal antibodies OKT4 and OKT4A. The results are discussed in terms of possible roles for immunoglobulin-related structures in human fertilization and in the sexual transmission of the acquired immunodeficiency syndrome.
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000276:immunology; D000911:Antibodies, Monoclonal; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D006681:HLA-D Antigens / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation; D008285:Major Histocompatibility Complex; D008297:Male; D011971:Receptors, Immunologic / Q000276:immunology; D013094:Spermatozoa / Q000166:cytology / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D006681:HLA-D Antigens; D011971:Receptors, Immunologic