Identification of a HSP14-3-3 in Setaria cervi and its cross-reactivity with W. bancrofti infected human sera

Abstract

Aim: Identification of a 29 kDa heat stress protein in filarial parasite Setaria cervi and evaluation of its diagnostic potential against lymphatic filariasis.

Methods and results: The Heat shock proteins (HSPs) were induced in filarial parasite S. cervi by incubated at 42 ◦C for 2 hrs. The 10% SDS PAGE of cytosolic extract showed several over-expressed bands. The MALDI LC/MS analysis of 29 kDa band showed 100% similarity with Bm14-3-3 like protein 2. Multiple sequence alignment of Bm14-3-3 like protein 2 sequence with W. bancrofti, Caenorhabditis elegans; Loa loa and Homo sapiens showed 100%, 86%, 83% and 78%, sequence similarity respectively. The antigenic efficacy of Sc14-3-3 protein was evaluated with different filarial sera using ELISA which showed cross reactivity in order to Endemic Normal(EN)<Microfilaraemic(MF)<Chronic(CH) with IgG1 and EN<CH<MF in IgG4 ELISA. IgG1 and IgG4 specific immunoblotting with CH and MF sera further explicated its specific antigenic cross-reactivity.

Conclusion: A 29 kDa heat shock protein of S. cervi was identified as 14-3-3 protein having 100% homology to human filarial parasite B. malayi. It showed strong reactivity with IgG1 and IgG4 subclass antibodies of W. bancrofti infected human sera suggesting that 14-3-3 protein could be used as a vaccine/ diagnostic marker.