CONTRIBUTION OF ALPHA BETA AND GAMMA/DELTA T-LYMPHOCYTES TO IMMUNITY AGAINST MYCOBACTERIUM-BOVIS BACILLUS-CALMETTE-GUERIN - STUDIES WITH T-CELL RECEPTOR-DEFICIENT MUTANT MICE/

Mutant mice with defined T cell deficiencies were infected with Mycoba cterium bovis bacillus Calmette Guerin (BCG) and the relative contribu tion of alpha/beta T cells and gamma/delta> T cells to the host immune response was assessed. Recombinase activating gene (RAG-1)(-/-) mutan ts as well as T cell receptor (TcR) beta(-/-), but not TcR-delta(-/-), mutants succumbed to M. bovis BCG infection and failed to develop gra nulomatous lesions. Antigen-induced IFN-gamma production by spleen cel ls in vitro was abrogated in RAG-1(-/-) mutants and markedly diminishe d in TcR-beta(-/-) and TcR-delta(-/-) mice. Reconstitution experiments suggest that both alpha/beta and gamma/delta T cells are essential fo r antigen-specific IFN-gamma secretion. Our data formally prove the cr ucial role of alpha/beta T cells and reveal accessory functions of gam ma/delta T cells in optimum immunity against M. bovis BCG.