02418nas a2200325   4500000000100000008004100001260001300042653001900055653001100074653002100085653001200106653002600118653001600144653004400160653001600204653001800220653002500238653003600263653001800299653003000317653001700347100001600364700001800380700001400398245012200412300001200534490000700546520152500553022001402078       1983                            d  c1983 Jun10aConcanavalin A10aHumans10aImmune Tolerance10aleprosy10aLymphocyte Activation10aLymphokines10aMacrophage Migration-Inhibitory Factors10aMacrophages10aMycobacterium10aMycobacterium leprae10aSuppressor Factors, Immunologic10aT-Lymphocytes10aT-Lymphocytes, Regulatory10aTime Factors1 aSalgame P R1 aMahadevan P R1 aAntia N H00aMechanism of immunosuppression in leprosy: presence of suppressor factor(s) from macrophages of lepromatous patients.  a1119-260 v403 a<p>Human peripheral blood mononuclear cell proliferation induced by Mycobacterium leprae could be inhibited by the suppressor factor in the lysate of the macrophages of lepromatous leprosy patients. Macrophages from normal subjects and tuberculoid patients did not show production of a suppressor factor. Inhibition occurred only when the factor was present in the initial stages of lymphocyte culture. The factor is heat stable and nondialyzable. Proliferation induced by some mycobacteria and concanavalin A could also be blocked by the factor. Interestingly, blastogenic response by a few other antigens and phytohemagglutinin could not be inhibited by the suppressor factor. Mononuclear cells pretreated with such lysate from lepromatous macrophages for 24 h could induce suppressive activity in the cells in vitro in an autologous system. Treatment of these cells with carbonyl iron after the induction phase, to remove phagocytic cells, did not abolish their suppressive activity. The lepromatous macrophage lysate also generated suppressive activity in a T-lymphocyte-enriched population of normal subjects. These studies are interpreted to indicate that immunosuppression in lepromatous patients is produced by both macrophages and T lymphocytes. The exact phase in which either of these cells acts as a suppressor may be different. Specific suppression by macrophages to M. leprae can be an early event, and nonspecific suppression by T lymphocytes may be a later event in the course of lepromatous leprosy.</p>  a0019-9567