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Leptospiral immunoglobulin-like protein (LigB) was truncated into conserved (LigBcon) and variable (varB1, varB2) fragments and expressed as GST/His-tag fusion proteins. Four-week-old hamsters were immunized with equal amounts of each fragment individually or combined in alum adjuvant at days 0 and 21 and subsequently challenged three weeks after the booster with 2.5 LD₅₀ live virulent Leptospira interrogans serovar Pomona. Our results demonstrate that immunization with LigB produced strong humoral immune responses as revealed by high titers against each fragment and significant enhancement in Th2 cytokines (IL-4, IL-10). A significant activation of CMI is revealed by enhanced proliferation of lymphocytes and up regulation of Th1 cytokines (IL-12p40, IFN-γ) was also noted. Of the peptides studied, rLigBcon was able to impart maximum protection (71%), followed by rVarB1 (54%), whereas …