A mushroom derived 'carbohydrate-fraction' reinstates host-immunity and protects from Leishmania donovani infection.

AIM The anti-leishmanial effect of the 'carbohydrate fraction' (designated as Ahf-Car ), isolated from an edible mushroom Astraeus hygrometricus, was evaluated against Leishmania donovani infection both in vitro and in vivo. METHODS AND RESULTS Ahf-Car induced the expression of inducible nitric oxide synthase 2 (iNOS2) and pro-inflammatory cytokines like TNF-α and IL-12, with subsequent down-regulation of the anti-inflammatory cytokines as TGF-β and IL-10, in vitro and in vivo along with a remarkable increase in the expressions of IL-6, IL-1β, IFN-γ, and IRFs, IRF-7 and IRF-8 in vivo. Ahf-Car also reduced the parasite burden in spleen and liver dose-dependently along with the proliferation of Ly6C+  cells in the bone marrow of Leishmania-infected experimental animals with an increase in monocyte population along with a dose-dependent increase in the expression of the myeloid transcription factor PU.1, in vivo. CONCLUSION Ahf-Car is capable of inducing the pro-inflammatory pathways of the anti-leishmanial immune responses in the hosts. Additionally, Ahf-Car -induced increased proliferation of Ly6C+  cells in the bone marrow and elevated expressions of PU.1 in a pro-inflammatory environment presumably signify the expansion of protective macrophages. Thus, Ahf-Car might be a potent anti-leishmanial lead with unique and effective adjuvant capacity.