Antiidiotype stimulation of antigen-specific antigen-independent antibody responses in vitro. I. Evidence for stimulation of helper T lymphocyte function.

Abstract

Antibodies specific for the idiotypes of B10 anti-(T,G)-A--L [synthetic polypeptide poly-L-(Tyr,Glu)-poly-D,L-Ala-poly-L-lysine] antibodies (anti-Id) induced in vivo (T,G)-A--L-primed lymphocytes [mouse] to secrete anti-(T,G)-A--L antibodies in vitro in the absence of antigen. Responses to anti-Id were quantitatively and qualitatively similar to responses to antigen. Responses were specific in that: only lymphocytes primed in vivo with (T,G)-A--L (but not other antigens or unprimed cells) were inducible; only anti-Id (but not a variety of control antibodies) induced responses and only anti-(T,G)-A--L antibodies were secreted. Antigen-primed T lymphocytes mixed with unprimed B plus accessory cells also responded to anti-Id; the phenotype of the responding T cells was Lyt-1+, Lyt-2-. Supernatants obtained from antigen-primed T cells incubated for 3 days with anti-Id (but not when incubated with controls) provided help to unprimed B plus accessory cells in the presence of anti-Id, thus providing direct evidence for induction of T lymphocyte helper function by anti-Id. In contrast to responses to (T,G)-A--L, responses to anti-Id did not appear to be regulated by H-2-linked Ir genes. The system described is a powerful tool for delineation of the mechanisms whereby antiidiotype antibodies affect lymphocyte function.