title: Subpopulations of B cells distinguished by cell surface expression of Ia antigens. Correlation of Ia and idiotype during activation by cloned Ia-restricted T cells.
abstract: We have investigated in vitro the induction of antibody responses to phosphorylcholine (PC) by cloned T helper (Th) cell lines. The cloned Th cells are antigen specific, in this case ovalbumin (OVA), self-Ia recognizing, and induce antibody secretion only if the hapten, PC, is physically linked to the carrier (OVA) molecule. The plaque-forming cell (PFC) response generated in the presence of cloned Th cells is idiotypically diverse with 5-40% of the secreting B cells bearing the TEPC-15 (T15) idiotype. The interaction of the cloned Th cells and unprimed B cells requires recognition of B cell surface Ia glycoproteins for all B cells activated to secrete anti-PC antibody, whether they be T15-bearing or not. More importantly, however, effective interaction between a cloned Th cell and a B cell is determined by the quantity of B cell surface Ia glycoproteins. Our results indicate that quantitative differences in B cell surface Ia antigens are directly related to B cell activation by the cloned Th cell. The high Ia density B cells are most easily activated by cloned Th cells, and these appear to be mainly non-T15-bearing. These data suggest that the failure of cloned Th cells to effectively activate T15-bearing B cells in vitro may be due to the lower relative Ia density of these B cells and therefore to their inability to interact effectively with cloned Ia-recognizing Th cells. These results imply that monoclonal T cells may distinguish between T15-bearing and non-T15-bearing B cells based on their Ia density.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology; D000921:Antibody-Producing Cells / Q000145:classification / Q000276:immunology; D001402:B-Lymphocytes / Q000145:classification* / Q000276:immunology; D002999:Clone Cells / Q000276:immunology; D000939:Epitopes; D006462:Hemolytic Plaque Technique; D000949:Histocompatibility Antigens Class II / Q000032:analysis* / Q000276:immunology; D007130:Immunoglobulin Idiotypes / Q000032:analysis*; D008213:Lymphocyte Activation; D051379:Mice; D008807:Mice, Inbred BALB C; D008808:Mice, Inbred CBA; D010047:Ovalbumin / Q000276:immunology; D010767:Phosphorylcholine / Q000276:immunology; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D000949:Histocompatibility Antigens Class II; D007130:Immunoglobulin Idiotypes; D010767:Phosphorylcholine; D010047:Ovalbumin