A lipopeptide facilitate induction of Mycobacterium leprae killing in host cells

Little is known of the direct microbicidal activity of t cells in leprosy,so a lipopeptide consisting of the n-terminal 13 amino acids lipopeptide (lipok) of a 33-kd lipoprotein of mycobacterium leprae,was synthesized. lipok activated m. leprae infected human dendritic cells (dcs) to induce the production of il-12. these activated dcs stimulated autologous cd4 + or cd8 + t cells towards type 1 immune response by inducing interferon-gamma secretion. t cell proliferation was also evident from the cfse labeling of target cd4 + or cd8 + t cells. the direct microbicidal activity of t cells in the control of m. leprae multiplication is not well understood. the present study showed significant production of granulysin,granzyme b and perforin from these activated cd4 + and cd8 + t cells when stimulated with lipok activated,m. leprae infected dcs. assessment of the viability of m. leprae in dcs indicated lipok mediated t cell-dependent killing of m. leprae. remarkably,granulysin as well as granzyme b could directly kill m. leprae in vitro. our results provide evidence that lipok could facilitate m. leprae killing through the production of effector molecules granulysin and granzyme b in t cells. © 2011 maeda et al.