IFNG and infection: Interestingly, immunization of Syrian Golden hamsters with single PS-sensitized and photo-inactivated L. amazonensisin vivo was shown to protect them against challenge infection with L. donovani: the splenic parasite load was drastically reduced by 99%, concomitant with significant increase in the expression of iNOS, IFN-γ, and IL-12 (Kumari et al., 2009).