02566nas a2200313   4500000000100000008004100001260001300042653002300055653002400078653001100102653002900113653002100142653001200163653002600175653002100201653002400222653002500246653002400271100001700295700001800312700001200330700001800342700001600360245013800376300001100514490000700525520170600532022001402238       1988                            d  c1988 May10aAntibody Formation10aAntigens, Bacterial10aHumans10aImmunosorbent Techniques10aInterferon-gamma10aleprosy10aLymphocyte Activation10aMolecular Weight10aMycobacterium bovis10aMycobacterium leprae10aPhytohemagglutinins1 aConverse P J1 aOttenhoff T H1 aGebre N1 aEhrenberg J P1 aKiessling R00aCellular, humoral, and gamma interferon responses to Mycobacterium leprae and BCG antigens in healthy individuals exposed to leprosy.  a515-250 v273 a<p>Protective immunity against mycobacteria is dependent on antigen-specific T cells. The antibodies induced upon immunization with mycobacteria have no apparent role in host protection. Serological techniques have detected some antigens that are also recognized by human T cells but may fail to recognize others. Potentially, there may be differences in the epitopes seen by the T and B cell anti-mycobacterial antigen repertoires. We have screened the different components of sonicated BCG or Mycobacterium leprae that were separated according to their molecular weight (MW) by SDS-PAGE and then electroblotted on nitrocellulose paper. The blots were cut into squares and tested directly in a T cell proliferation assay. Our results indicate that peripheral T cells of healthy leprosy patient contacts respond preferentially to the lower MW (less than 70,000) and not the higher MW fractions of M. leprae and BCG, in contrast to the humoral response of these same individuals. The most important fractions in inducing a lymphoproliferative response were in the regions of 11-16 kDa of BCG and M. leprae and to the 22-26 kDa region of M. leprae. These fractions appeared to represent molecular weight regions that were in some instances clearly distinct from previously defined antigens. It was further shown that lymphoproliferation in response to mycobacterial fractions correlated with the production of gamma interferon, a lymphokine required for macrophage activation and elimination of mycobacteria. These studies allow the direct assessment of antigens involved in protective T cell-mediated immunity, and should be helpful in selecting relevant antigens for skin testing and immunization.</p>  a0300-9475