Invivo and Invitro studies on carboxy terminal domains of leptospiral immunoglobulins of L. interrogans Icterohaemorrhagiae

Carboxy terminal domains of leptospiral immunoglobulins of r Lig A and r Lig B were assessed its hemolytic, cytotoxicity effects invitro and its protective efficacy was studied in hamster models. Experimental recombinant proteins of Leptospira interrogans Icterohaemorrhagiae were individually cloned, expressed in prokaryotic system. Purified expressed proteins confirmed by western blot, assessed for its protective efficacy using hamster models. 100% and 93% protection on homologues challenge was observed with r Lig A and r Lig B with adjuvant respectively which is evident with increased levels of antibody levels of r Lig A and r Lig B with 98% and 95% specificity. Cytotoxicity was maximum with 14% in Daudi cells with with r Lig B and 7% and r Lig A. 17% and 4% hemolytic activity with r Lig A, and r Lig B protein and 11% and 10% in pH-7.0 respectively. E. coli (harboring pET15b) membrane fraction used as placebo neither exerted cytotoxicity nor hemolysis was used to compare the leptospiral proteins. Leptospiral immunoglobulins showed least cytotoxicity and hemolytic activity with increased homologues protection in experimental animals Keywords: Leptospira recombinant protein, Leptospiral immunoglobulins, immune response, challenge studies, cytotoxic and hemolytic activity. REFERENCES Alves, V.A., Gayotto, L.C., Brito, T.De., Santos, R.T., Wakamatsu, A., Vianna, M.R., and Sakata. E.E (1992). Leptospiral antigens in the liver of experimentally infected guinea pig and their relation to the morphogenesis of liver damage. Exp. Toxicol. Pathol. (44): 425-434. Andre-Fontaine, G., Branger, C., Gray, A.W and Klaasen, H.L. (2003). Comparison of the efficiacy of three commercial bacterins in preventing canine leptospirosis. Vet. Rec. (153): 165-169. Bartlett, J.M.S. and Stirling, D. (2004). DNA Extraction form Fungi, Yeast and Bacteria. PCR Protocols Second Edition, Methods in Molecular Biology, Humana Press, (226): 53-54. Bernheimer, A.W. and Bey, R.F. (1986). Copurification of Leptospira interrogans serovar ...