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An attempt was made to study the immunoprophylactic efficacy of recombinant Brugia malayi transglutaminase (BmTGA) as protein vaccine along with two other recombinant proteins, Brugia malayi abundant larval transcript-2 (BmALT-2) and Brugia malayi thioredoxin peroxidase (BmTPX), in single and multiple antigen form for human lymphatic filariasis. Parasite challenge studies in jirds exhibited protection of 30%, 69%, and 43% against BmTGA, BmALT-2, and BmTPX, respectively, in single antigen vaccination mode. The protective efficacy of BmTGA was enhanced significantly (74%) by immunizing the jirds in multiple antigen vaccination mode along with BmTPX, whereas immunizing with the combination of BmTGA and BmALT2 conferred only 47% protection. The same protection profiles were obtained by in vitro antibody-dependent cellular cytotoxicity, using live microfilariae and L3 stage larvae. The immune response was Th2 biased, irrespective of single or multiple vaccinations. The combination of BmTGA and BmTPX seems to be a promising vaccine candidate against lymphatic filariasis.

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The present research was undertaken to study the probiotic characteristics of Pichia kudriavzevii isolated from frozen idli batter. Polymerase chain reaction amplification with 18S rRNA primers confirmed Pichia kudriavzevii, a xylose-utilizing probiotic strain. It was resistant to physiological concentrations of bile salts, pepsin and pancreatic enzyme. It also showed efficient auto-aggregation as well as co-aggregation ability with four commercial probiotic yeasts and exhibited good hydrophobicity in xylene and toluene. The strain inhibited the growth of 13 enteropathogens and showed a commensal relationship with four commercial probiotic yeast and bacteria. Moreover, it was resistant to 30 antibiotics with different modes of action. The yeast exhibited thermotolerance up to 95°C for 2 h. The cell-free supernatants were also found to be heat stable, indicating the presence of thermostable secondary metabolites. Hence it could be exploited as starter culture, co-culture or probiotic in the preparation of fermented products or incorporated in heatable foods as well.

A homologue of Brugia malayi venom allergen (BmVAH) was cloned from the infective stages (L3) of Wuchereria bancrofti. Sequence analysis showed 90% sequence identity between WbVAH and BmVAH. Recombinant WbVAH was then expressed and purified. VAH from other nematode parasites is being evaluated as potential vaccine candidates. Because W. bancrofti infections are more prevalent than B. malayi, it will significantly benefit using W. bancrofti antigens for vaccine development. In this study, we have evaluated the human immune responses to rWbVAH in putatively immune individuals who live in the endemic regions (endemic normal, EN) to determine the vaccine potential of WbVAH. These responses were then compared to those in infected individuals (microfilaraemic, MF and chronic pathology, CP). Results show that EN subjects carry WbVAH-specific IgG1, IgG2, and IgG3 circulating antibodies. It is interesting to note that CP patients also carried antibodies against WbVAH that was mainly of the IgG3 isotype. Peripheral blood mononuclear cells (PBMC) from EN individuals responded strongly to rWbVAH by proliferating and secreting IFN-γ. PBMC from MF patients also proliferated in response to rWbVAH but secreted mainly IL-10. Thus, there was a clear dichotomy in the cytokine production by infected patients vs individuals who are putatively immune (EN). Although vaccine potential of WbVAH has not been established yet, our findings suggest that WbVAH mediated immune responses in EN individuals is primarily Th1-biased. Further vaccination studies are underway in animal models to determine the role of WbVAH in protective immunity against W. bancrofti and B. malayi infections.