Recombinant Wolbachia Surface Protein from Brugia malayi modulates human monocyte function in vitro.

Kalyanaraman, H.; Vijayan, K.; Sreenivas, K.; Babu, S.; Narayanan, R.B.

International Trends in Immunity; 2014; 2; 53-61.

Abstract: Wolbachia , an endosymbiont that resides inside the parasite Brugia malayi contributes to the pathogenesis of human filarial infections. In order to examine the immunomodulatory effects of Wolbachia proteins, recombinant Wolbachia surface protein (rWSP) was produced and its effect on human monocytes in vitro was studied. rWSP reduces the phagocytic ability of THP-1 macrophages and does not influence the release of nitric oxide post phagocytosis. This was further supported by insignificant alteration in iNOs gene expression in rWSP treated THP-1 cells. rWSP induces the gene expression of pro-inflammatory cytokines IL-1ß, TNF- a and IL-6 in addition to diminished IL-12 and IL-10 gene expression in THP-1 cells. The role of rWSP in apoptosis of peripheral blood mononuclear cells from endemic normal individuals suggests that this protein initiates apoptosis of monocytes and not lymphocytes. This was further confirmed with purified monocytes from the same individuals. These observations suggest that rWSP down-regulates human monocyte function in vitro and thus promotes parasite survival leading to the filarial disease in humans.

Keywords: Apoptosis; Cytokines; Macrophage; Phagocytosis; THP-1 cells; Wolbachia

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