Recombinant translation initiation factor-1 of Wolbachia is an immunogenic excretory secretory protein that elicits Th2 mediated immune protection against Brugia malayi

Abstract

Wolbachia, the intracellular alpha-proteobacteria are required for the development, fertility and survival of filarial parasites. Wolbachia Translation initiation factor-1 (Wol Tl IF-1) is one of the factors required for Wolbachia growth and viability. In the present study, we cloned, over expressed and purified Wol Tl IF-1 that exhibited strong immuno-reactivity with various categories of bancroftian sera. Immunization with the recombinant protein resulted into significant reduction in microfilarial density (70-72%) and adult worm establishment (61-63%) in susceptible Mastomys coucha. Protection offered by Wol Tl IF-1 was found associated with humoral immune arm as observed by an increased antibody level with preponderance of IgE, IgM, IgG1 and IgG2a isotypes. The anti-Wol Tl IF-1 antibodies promoted profound adherence of peritoneal exudates cells to the surface of microfilariae and infective larvae causing cytotoxicity and their death. The present study indicates potential of recombinant Wol Tl IF-1 as a promising vaccine candidate against human lymphatic filarial infection.