On the basis of the fact that recovery from VL is always associated with immunity to subsequent infection and induction of Th1 cytokines dominated by IFN-γ, we identified several Th1 stimulatory proteins from soluble fraction and sub-fraction of L. donovani ranging from 89.9 to 97.1 kDa through proteomics which was also found to be protective against experimental VL [15], [16], [52]. This evidence concerns the gene IFNG and infection.