INTERFERENCE BETWEEN NEISSERIA-MENINGITIDIS AND PC-KLH INDUCED ANTIPHOSPHORYLCHOLINE PFC RESPONSES IN NZB W AUTOIMMUNE MICE/

In this work, we demonstrate that the simultaneous injection of PC-KLH and Neisseria meningitidis-derived antigens [NMB or PC-(NMB)HI] induc ed in old NZB/W mice defective responses as does PC-KLH challenge. On the other hand, the simultaneous injection of both immunogenic prepara tions of N. meningitidis evoked responses similar to those shown by ol d mice challenged with NMB alone. Alteration in PC-specific PFC respon ses also affected hapten-free inhibition profiles and their heterogene ities. The increase in PC(50)s of anti-phosphorylcholine PFC responses and their heterogeneities induced by certain antigens with aging is c orrelated with a decrease in T15 idiotype expression, suggesting that after the T15 dominant clone disappears no other clone takes control o f the anti-PC response. These results suggest that the mechanism(s) in volved in the regulation of T15 marker expression play an important ro le in the inability of old NZB/W mice to mount good anti-PC responses and suggest that regulatory mechanisms induced by PC-KLH dominate thos e elicited by NMB.