Expression analyses of interferon gamma, tumor necrosis factor alpha and inducible nitric oxide synthase in the hemocyte morphotypes of two commercially important Indian molluscs

• First report of IFNγ, TNFα and iNOS in the hemocytes of Indian molluscs.
• IFNγ expression was higher in the agranulocytes and semigranulocytes of Bellamya bengalensis and Lamellidens marginalis.
• Expression of TNFα was more prominent in the agranulocytes and semigranulocytes in both experimental specimens.
• In B. bengalensis, iNOS expression was recorded to be the highest in semigranulocytes followed by agranulocytes, granulocytes.
• Nonidentical expression of IFNγ, TNFα and iNOS in two species was indicative to species specific immune status of mollusc.

Bellamya bengalensis and Lamellidens marginalis are the two common species of molluscs of Indian subcontinent which bear immense aquacultural prospect. These edible varieties of freshwater molluscs have nutritional, ecological, ethnomedicinal and industrial significance. Report of nonspecific immunological status of them is grossly inadequate in the current scientific literature. Hemocytes, the circulating blood cells of invertebrate molluscs play a pivotal role in cell mediated immunity. Information of existence of cytokines like IFNγ, TNFα and enzyme iNOS is very limited and controversial in molluscan hemocytes. We detected IFNγ, an immunomodulatory molecule and TNFα, a tumoricidal and apoptosis inducing cytokine in hemocyte morphotypes of molluscs B. bengalensis and L. marginalis by flow cytometry, iNOS had been detected in the hemocyte morphotypes of B. bengalensis and not in L. marginalis. We report the existence of IFNγ in molluscs for the first time. Comparative expression of IFNγ, TNFα and iNOS in hemocytes would provide a better information base to understand biology, evolution and immunological role of these molecules in molluscs and related metazoans.