THE SUPPRESSIVE EFFECT OF MYCOBACTERIUM-LEPRAE ON THE INVITRO PROLIFERATIVE RESPONSES OF LYMPHOCYTES FROM PATIENTS WITH LEPROSY

Abstract

Peripheral blood lymphocytes from 60 leprosy patients and 8 healthy contacts known to be responsive to M. leprae were stimulated in vitro with concanavalin (Con) A or PPD [purified protein derivative] alone or in combination with autoclaved, whole M. leprae. Time kinetics and the percentage of inhibition induced by M. leprae differed in the 2 disease groups and contacts. Antigen-generated suppression of Con A-stimulated lymphocyte transformation was observed on day 4 in 17 of 21 (80%) tuberculoid patients, and 6 of 17 (35.3%) untreated lepromatous patients. Healthy contacts and 53% of the lepromatous individuals showed enhanced Con A responses in the presence of antigen. On prolongation of antigen presence to 6 days, a marginal effect was noted in the tuberculoid group. All healthy individuals and some lepromatous patients showed increased inhibition of Con A responses. M. leprae antigens showed uniform inhibition of PPD-induced 3H-thymidine incorporation in leprosy patients and healthy contacts.