Stimulation by anti-idiotype antibody of murine T cell responses to the 38 kD antigen of Mycobacterium tuberculosis.

Rabbit antisera raised against eight monoclonal antibodies (MoAb) binding to distinct mycobacterial antigens revealed individual anti-idiotype specificities following cross-absorption with normal mouse globulin. Only one of these antibodies (Rb71), directed towards an M. tuberculosis-specific epitope on the 38 kD protein antigen was able to stimulate mouse T cell responses which had 'internal image' characteristics. This was demonstrated by anti-Id induced in vitro proliferation of Lyt 1.2+ T cells and the elicitation of delayed type hypersensitivity (DTH) foot pad reactions in antigen stimulated BALB/c mice. The DTH reaction was equally strong in mice sensitized with either M. tuberculosis or M. bovis soluble extracts, thus showing a greater degree of cross-reactivity than antibody binding of the corresponding TB71 MoAb. The immunizing potency of the anti-Id in vivo was demonstrable in three strains of mice following injection of Rb71 emulsified with incomplete Freund's adjuvant. These mice showed 38 kD antigen induced DTH-reactions as well as in vitro proliferation of spleen cells. The display of T cell stimulatory internal image by anti-Id may be interpreted as a consequence of binding specificity of TB71 MoAb of a T cell epitope present in the 38 kD antigen.