title: Characterization by a monoclonal antibody and functional analysis of a subset of bovine T lymphocytes that express BoT8, a molecule analogous to human CD8.
abstract: Monoclonal antibody (mAb) IL-A17 characterizes a subset of bovine T lymphocytes. IL-A17 recognizes a 34,000-35,000 MW doublet, designated BoT8, which is expressed on the surface of approximately 20% of peripheral blood mononuclear leucocytes (PBM), a subpopulation of lymphocytes in T-dependent areas of lymph nodes and spleen, and about 70% of thymocytes. This molecule is not expressed on B lymphocytes, monocytes/macrophages or granulocytes. Double labelling of PBM showed that the BoT8+ population is distinct from the T lymphocyte subset expressing BoT4. BoT8+ lymphocytes purified with a fluorescence-activated cell sorter (FACS) proliferated poorly in response to mitogenic and alloantigenic stimulation in the absence of exogenous growth factors. IL-A17 had no inhibitory effect on proliferation of PBM to mitogens (Con A and PHA) or alloantigens and no measurable effect on the in vitro generation of cytolytic effector cells. However, in some experiments IL-A17 was found to block partially allospecific cytolytic function mediated by bulk effector cell populations when included in 51Cr-release assays. Fractionation of effector cells generated in an allogeneic mixed leucocyte culture (MLC) demonstrated that cytotoxic cells specific for class I major histocompatibility complex (MHC) antigens reside within the BoT8+ population. Based on these data, and information reported elsewhere on alloreactive bovine T-cell clones, BoT8 is considered to be analogous to CD8 in humans and equivalent molecules in other species.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D001853:Bone Marrow / Q000276:immunology; D002417:Cattle; D002469:Cell Separation; D003602:Cytotoxicity, Immunologic; D000939:Epitopes / Q000032:analysis*; D005434:Flow Cytometry; D006801:Humans; D007124:Immunoenzyme Techniques; D007519:Isoantigens / Q000276:immunology; D008213:Lymphocyte Activation; D008221:Lymphoid Tissue / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008934:Mitogens / Q000494:pharmacology; D013601:T-Lymphocytes / Q000145:classification*
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D007519:Isoantigens; D008934:Mitogens