Immunotherapeutic potential of Leishmania (Leishmania) donovani Th1 stimulatory proteins against experimental visceral leishmaniasis

An effective therapeutic vaccination strategy is required for controlling visceral leishmaniasis (VL), a fatal systemic disease, through boosting the immunosuppressed state in Leishmania-infected individuals, as the majority of them living in the endemic regions exhibit either subclinical or asymptomatic infection which further often develops into a full-blown disease. Previously in our laboratory, several Th1 stimulatory recombinant proteins were successfully cloned, purified and assessed for their prophylactic efficacy against Leishmania challenge. Due to their immunostimulatory property, these proteins are needed to be evaluated for their immunotherapeutic potential in Leishmania-infected hamsters. Four proteins namely, aldolase, enolase, p45 and triose phosphate isomerase were taken up to immunize animals at different doses (50, 25 and 12.5 μg/animal). Immunization with lower doses of aldolase and enolase, i.e., 25 and 12.5 μg showed a significant decline (∼60%) in parasitic load along with an enhanced cellular immune response. These findings indicate that vaccination with above -stated Th1 stimulatory proteins is an effective immunotherapeutic approach against experimental VL. However, their efficacies may further be improved in combination with known therapeutic regimens or immunomodulators.