Antibody response to phosphorylcholine in vitro. II. Analysis of T-dependent and T-independent responses.
Spleen cells from BALB/c mice primed with keyhole limpet hemocyanin (KLH), were stimulated with heat-killed vaccine of rough Pneumococcus pneumoniae R36A (Pn) and/or phosphorylcholine (PC)-coupled KLH to induce an anti-PC response in vitro. The response to PC-KLH was found to be T-dependent while it is T-independent to Pn. The antibodies induced with either antigen had similar avidity and expressed the TEPC 15 idiotype exclusively; thus T cell involvement in the response to PC-KLH failed to alter these parameters of the anti-PC response. At the precursor cell level, Pn induced small clones with an average size of 10 plaque-forming cells (PFC), whereas PC-KLH gave rise to larger clones of 40-50 PFC. This difference in the proliferative potential of PC precursor B cells hinted at the possibility that Pn and PC-KLH were stimulating different precursors. This was corroborated by the observation that a) when Pn and PC-KLH were added to the same cultures a synergistic effect was seen, i.e. the number of plaques was greater than the sum of the responses induced by each antigen, and b) in microcultures, under conditions limiting B cells only, Pn plus PC-KLH induced a higher fraction of responding wells than either antigen on its own. We postulate that Pn and PC-KLH stimulate subpopulations of PC precursor cells which are T-independent and T-dependent, respectively.
D000818:Animals; D000917:Antibody Formation; D001402:B-Lymphocytes / Q000276:immunology*; D001666:Binding Sites, Antibody; D002352:Carrier Proteins / Q000276:immunology; D002794:Choline / Q000031:analogs & derivatives*; D002999:Clone Cells / Q000276:immunology; D005260:Female; D006433:Hemocyanins / Q000276:immunology; D007126:Immunoglobulin Allotypes; D051379:Mice; D008807:Mice, Inbred BALB C; D010767:Phosphorylcholine / Q000276:immunology*; D013154:Spleen / Q000276:immunology; D013296:Streptococcus pneumoniae / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology*
D002352:Carrier Proteins; D007126:Immunoglobulin Allotypes; D010767:Phosphorylcholine; D006433:Hemocyanins; D002794:Choline