Immunological evaluation of fusion protein of Brugia malayi abundant larval protein transcript-2 (BmALT-2) and Tuftsin in experimental mice model

Introduction: Filariasis, a neglected tropical helminth disease needs vaccine besides mass drug administration for its successful eradication. Methods: An attempt was made to produce a fusion protein (P-TUFT-ALT-2) of abundant larval transcript protein-2 and Tuftsin to enhance its immunogenicity. The fusion construct was expressed in Pichia pastoris, a nonexpensive commercial expression system. This study focused on the evaluation of immunological response produced by P-TUFT-ALT-2 in Balb/c mice. Result and discussion: P-TUFT-ALT-2 showed an enhanced IgG peak titre compared to E. coli expressed E-ALT-2 and P. pastoris expressed P-ALT-2. IgG2b, IgG2a and IgG1 production were predominant indicating a balanced Th1/Th2 response. P-TUFT-ALT-2 also induced about 28% and 9.5% higher splenocyte proliferation over control and E-ALT-2 respectively. Splenocytes produced predominant IFN-γ followed by IL-5, IL-2 and IL-10 specifying a balanced Th1/Th2 response. P-TUFT-ALT-2 showed 55% to 80% with an average of 65% cytotoxicity in B. malayi L3 larvae in in vitro ADCC assay. Conclusion: This experiment validates P-TUFT-ALT-2 as a potential vaccine candidate for human lymphatic filariasis. Keywords: Lymphatic filariasis, Abundant larval transcript-2, Tuftsin, Vaccine candidate, Pichia pastoris, Balb/c mic