Visceral leishmaniasis (VL) is a neglected tropical disease with high mortality and limited treatment options. Amphotericin B (AmB) remains the most effective drug but is constrained by dose-dependent Show more
Visceral leishmaniasis (VL) is a neglected tropical disease with high mortality and limited treatment options. Amphotericin B (AmB) remains the most effective drug but is constrained by dose-dependent toxicity. Immunotherapy using parasite-derived components may potentiate host defenses and host protective responses and attenuate drug-induced cytotoxicity. This study investigated the therapeutic efficacy and immune response-modulating mechanism of AmB in combination with ultradiluted Leishmania antigen (udLA) in a murine model of VL. BALB/c mice were experimentally infected with L.donovani promastigotes and subsequently treated with AmB, udLA, or their combination. Parasite burden in hepatic and splenic tissues was quantified via Leishman-Donovan Units and quantitative PCR. Cellular immune responses were characterized by flow cytometric analysis of CD4 All therapeutic regimens significantly reduced parasite load relative to untreated controls, with the AmB+udLA combination achieving up to 96% reduction. Combination therapy elicited pronounced expansion of CD4 Co-administration of AmB with ultradiluted Leishmania antigen markedly enhances antileishmanial efficacy through potentiation of Th1-biased immune response and activation of macrophage effector mechanisms, while concurrently minimizing drug induced toxicity. These findings underscore the potential of udLA as a rational safer strategy for the management of VL. Show less