Long-lasting thymus-independent immune responses to anti-idiotype lipopolysaccharide conjugates require continuous B cell renewal.

In the present investigation, we have studied the antibody response of both C57BL/6 lipopolysaccharide-responder mice (B6 LPS-R) and C57BL/10ScCr LPS-nonresponder mice (B10.Cr LPS-NR) upon immunization with copolymers of LPS and either Ac38 or Ac46 anti-idiotypes. As both strains of mice studied are of the Ighb allotype the antibody response obtained was quantified by estimating the serum levels of the complementary idiotype, B1-8, in immunized mice. The results show that while the injection of the LPS-R strain B6 with copolymers of LPS anti-idiotype resulted in a long-lasting idiotype response the immunization of the LPS-NR strain, B10.Cr, resulted in virtually no response. This finding allowed us to perform cell transfer experiments to study the response of isolated cells from B6 mice transferred into LPS-NR hosts. Using such a cell transfer model, the results obtained suggest that long-lasting idiotype responses observed in the LPS-R strain require continuous B cell production in bone marrow. The relevance of this finding to the understanding of the long-lasting (fluctuating) antibody responses to nondegradable thymus-independent polysaccharides is discussed.