A 38-KDA ANTIGEN OF MYCOBACTERIUM-TUBERCULOSIS PREDOMINANTLY INDUCES THE SECRETION OF INTERLEUKIN-2, INTERFERON-GAMMA AND IGG2A ANTIBODIES

In the present study, mice of 3 different haplotypes (H-2d, H-2k and H -2b) were sensitized subcutaneously with heat-killed H37Ra or 38-kDa a ntigen of Mycobacterium tuberculosis. Lymphocytes obtained from immuni zed animals were challenged in vitro with 38-kDa antigen in both cases . The dominant pattern of Th1-like lymphokines (IL-2 and IFN-gamma) an d preferential production of 38-kDa specific IgG2a-type antibody were observed, It was noted that 38-kDa antigen was recognized permissively by all 3 strains of mice used in the present study. It was interestin g to note that C3H/HeJ mice, which express BCG-resistant alleles showe d a higher level of proliferative as well as cytokine response as comp ared to BALB/c and C57BL/6 mice, which bear BCG-susceptible alleles. T hese results suggest that not only in recall responses but also during the induction as well as expression phase of the immune response medi ated by 38-kDa antigen of M. tuberculosis the Th1-like immune response predominates.