The response of human B cells to Mycobacterium leprae. Identification of target antigens following polyclonal activation in vitro.
We have investigated the B cell response to Mycobacterium leprae in leprosy patients and healthy controls. A comparison of Western-blotted proteins separated by two-dimensional gel electrophoresis and probed with pooled sera from LL and BT patients revealed distinct antigen recognition patterns for the two classifications of the disease. To characterize the circulating B cells capable of producing anti-M. leprae antibodies in vitro, peripheral blood lymphocyte cultures were activated polyclonally with an anti-CD3 mAb. The resulting culture supernatants were used to probe Western-blotted M.leprae proteins and contained antibody reactive with a 10 kd M.leprae antigen. This antibody was absent in stimulated culture supernatants from healthy occupational contacts or unexposed controls, suggesting the specificity of the response. Distinct repertoires of serum and culture supernatant anti-M.leprae antibodies were observed when Western-blotted antigens were probed after two-dimensional gel electrophoresis. This method for assay of specific antibody production against individual components present in a complex mixture of antigens after polyclonal activation in vitro may be used to study the regulation of B cell activation in leprosy and other diseases.