Using mass spectrometry and immunological approaches, a heat shock protein 70 associated with lymphatic filariasis (LF) has been identified from a bovine filarial parasite Setaria cervi. A heat shock protein was detected in different life stages of S. cervi when exposed to an elevated temperature of 44 degrees C. A combination of ATP-agarose column chromatography and electro-elution was used for its purification from adult female extract. On closer examination, it migrated as a single band at 68 kDa on 10% SDS-PAGE. Peptide sequences TTPSYVAFTDTER, DSGAIAGLNVLR, IINEPTAAAIAYGLDK, NALESYAFNMK and LLSDFFSGK were obtained through MALDI-LC/MS analysis. Confirmation of peptides was accomplished by MASCOT database which showed substantial sequence homology with S. digitata, Wuchereria bancrofti, and Caenorhabditis elegans. Multiple sequence alignment using Clustal W showed 98% identity with W. bancrofti and only 28% with human HSP70. Furthermore, the antigenicity plot has shown that the highly antigenic amino acid residues are constituted within the conserved peptides. These observations suggest a plausible biological connection of ScHSP70 with the disease and its strong immunogenic nature. ScHSP70 showed antigenic cross-reactivity with IgG class of antibody in different categories of filarial sera. However, when IgG subclasses were tested, IgG4 showed high specificity and sensitivity with asymptomatic microfilaraemic sera.
(c) 2009. Published by Elsevier Ltd.