Detection of shared antigenic determinants between Mycobacterium leprae heat shock protein 65 and human heat shock protein 60

Resumo

In these studies, it was investigated whether M. leprae and man share antigenic determinants which may be located on Heat Shock Proteins (HSPs), and which may be responsible for tissue destruction. Using immunoperoxidase singlestaining technique on cryostat sections it was observed that three antibodies which are directed against HSP 60 (polyclonal antibodies SPA 804 and SPA 805 and monoclonal antibody SPA 807) probably reacted specifically with macrophages and epitheloid cells in leprosy skin sections. On Western Blotting, it was observed that the antibodies against human HSP 60 and monoclonal antibodies (MoAbs) against M. leprae HSP 65 (F 47-10, F 67-18, F 88-1) all reacted strongly with sonicated M. leprae proteins with a molecular mass of 65 kDa indicating similarity of some antigenic determinants between human HSP 60 and M. leprae HSP 65. Subsequently, a comparative immunohistochemical study of the staining patterns of antibodies against human HSP 60 and antibodies against M. leprae HSP 65 using cryostat skin sections of paucibacillary (PB) leprosy, multibacillary (MB) leprosy and other granulomatous skin disorders revealed that the MoAbs F 47-10 and F 67-18 reacted only weakly with the granulomas in PB leprosy and in other granulomatous skin diseases, but stained MB leprosy granuloma strongly. The MoAb F 88-1 and the polyclonal antibodies SPA 804, SPA 805 and the MoAb SPA 807 stained granulomas of PB patients and of other granulomatous skin disorders with the same intensity as that MB patients. Using a double-staining technique, it was observed that the antigenic determinants recognized by the MoAb against human HSP 60 (SPA 807) and the MoAbs against M. leprae HSP 65 (F 67-18, F 47-10, F 88-1) were mostly located in the macrophages. These findings do not contradict our suggestion, that similarities between antigenic determinants on Heat Shock Proteins of M. leprae and the human host may be at least in part responsible for the induction of an autoimmune reaction causing granuloma formation with subsequent tissue damage in leprosy. The results of this study also indicated that some of these determinants are probably located on HSP 60. A similar explanation possibly applies to the findings in the other granulomatous diseases, e.g. sarcoidosis probably mycobacterial induced and necrobiosis lipoidica related to diabetis, in which antigenic similarities between bacterial HSP 65 and human HSP 60 are considered to play a part.