@article{15370, keywords = {Animals, Concanavalin A, Humans, Immune Tolerance, Interleukin-2, leprosy, Lymphocyte Activation, Mice, Mice, Inbred C57BL, Mycobacterium Infections, Mycobacterium leprae, T-Lymphocytes, T-Lymphocytes, Regulatory, Tuberculin}, author = {Bach M A and Hoffenbach A and Lagrange P H and Wallach D and Cottenot F}, title = {Mechanisms of T-cell unresponsiveness in leprosy.}, abstract = {

We analysed the mechanisms of T-cell unresponsiveness to Mycobacterium leprae antigens and to unrelated antigens or T-cell mitogens in human leprosy and in an experimental model of murine infection by M. lepraemurium (MLM). In human leprosy, monoclonal antibodies OKT3, OKT4 and OKT8 were used to enumerate T-cell subpopulations within peripheral blood. Increased percentages of OKT8+ cytotoxic/suppressor cells were observed in untreated, non-reactional lepromatous patients. Conversely, lepromatous patients suffering from erythema nodosum leprosum, an Arthus-like phenomenon, exhibited a transient drop in the percentage of OKT8+ cells with a correlative increase in the proliferative response to T-cell mitogens. We studied the proliferative response to M. leprae of OKT4+ and OKT8+ cells isolated by a negative selection procedure using antibody-induced cytotoxicity plus complement. None of these subpopulations proliferated when incubated with M. leprae. In some patients, control treatment of mononuclear cells with complement alone induced the reappearance of a strong proliferative response to M. leprae, suggesting the existence of an active suppressor mechanism through soluble factors of an unknown nature. In MLM-induced murine leprosy, a progressive decrease was observed in the proliferative response to concanavalin A (ConA), and an early decrease in interleukin 2 activity in supernatants from ConA-stimulated spleen cells. Splenic T cells from MLM-infected mice transferred into naive recipients accelerated the local MLM growth in these recipients, suggesting that suppressor T cells may play a pathogenic role in the progression of MLM infection.

}, year = {1983}, journal = {Annales d'immunologie}, volume = {134D}, pages = {75-84}, month = {1983 Jul-Aug}, issn = {0300-4910}, language = {eng}, }