Immunomodulatory role of arabinosylated lipoarabinomannan on Leishmania donovani infected murine macrophages.

Arabinosylated lipoarabinomannan (Ara-LAM), a surface glycolipid antigen isolated from avirulent Mycobacterium smegmatis is involved in modulation of host cell signaling. In this study, we investigated Ara-LAM-mediated modulation of impaired immune responses during visceral leishmaniasis caused by protozoan parasite Leishmania donovani. Ara-LAM treatment at dose of 3 microg/ml in L. donovani infected murine peritoneal macrophages as well as J774A.1 macrophage cell line exhibited a distinct up-regulation of pro-inflammatory cytokines like TNF-alpha and IL-12 both at the protein and transcriptional level. In addition, generation of nitric oxide and iNOS expression were also observed. The present study showed that Ara-LAM was significantly effective in elimination of L. donovani parasites from both peritoneal as well as J774A.1 macrophages. Thus, it could be utilized as an immunomodulatory agent in prevention of leishmanial pathogenesis.