Idiotype and antigen-specific T cell responses in mice on immunization with antigen, antibody, and anti-idiotypic antibody

Idiotypic determinants of immunoglobulin molecules can evoke both CD4(+) an d CD8(+) T responses and exist not only as the integral components of a bon a fide antigen binding receptor but also as distinct molecular entities in the processed forms on the cell surface of B lymphocytes. The present work provides experimental evidence for the concept that regulation of memory B cell populations can be achieved through the presentation of idiotypic and anti-idiotypic determinants to helper and cytotoxic cell (1). The potential of B cells to present antigens to helper and cytotoxic T cells through cla ss II and class I MHC suggests a mechanism by which both B and T cell homeo stasis can be maintained. We provide evidence for the generation of idiotyp e- and antigen-specific Th and Tc cells upon immunization of syngenic mice with antigen or idiotypic antibody (Abl) or anti-idiotypic antibody (Ab2). The selective activation and proliferation of the antigen-specific Th and T c cells mediated by idiotypic stimulation observed in these experiments sug gests a B-cell-driven mechanism for the maintenance of antigen-specific T c ell memory in the absence of antigenic stimulation, under certain condition s. (C) 2001 Academic Press.