IGG RESPONSE TO PURIFIED 65-KDA AND 70-KDA MYCOBACTERIAL HEAT-SHOCK PROTEINS AND TO ANTIGEN-85 IN LEPROSY

IgG antibody response to mycobacterial heat-shock proteins (hsp) (the 70-kDa antigen from Mycobacterium tuberculosis and M. bovis BCG; the 6 5-kDa antigen from M. leprae and M. bovis BCC) and to the fibronectin- binding antigen 85 from M. bovis BCG was analyzed in a dot-blot assay in plasma from leprosy patients and their contacts. Most plasma-whatev er the status of the subjects-reacted to the hsp 70; 8 of 9 (89%) of p aucibacillary patients recognized the 65 mycobacterial hsp but only 2 of 9 (22%) recognized the antigen 85. In contrast, 12 of 12 (100%) of multibacillary patients reacted with the antigen 85 and only 4 of 12 ( 33%) reacted to the hsp 65 from M. leprae. On the one hand, 7 of 25 (2 8%) of the lepromin-positive contacts and 2 of 9 (22%) of the lepromin -negative contacts recognized the antigen 85. On the other hand, 11 of 25 (44%) of the lepromin-positive contacts but only 1 of 9 (11%) of t he lepromin-negative contacts reacted to the hsp65 from M. leprae. Fin ally, very few (10%) of the lepromin-positive controls showed a positi ve reaction to the M. leprae 65-kDa antigen, the BCG 65-kDa antigen, a nd the 85-kDa antigen of BCG. Thus, differences in binding to the hsp6 5 from M. leprae and to antigen 85 could be helpful in distinguishing different forms of the disease.