Toll like receptor induces Ig synthesis in Catla catla by activating MAPK and NF-κB signalling

[Display omitted] •TLR induction differentially activates fish immunoglobulin (IgZ, IgM) expression.•ERK and NF-κB play crucial role in TLR-mediated IgZ and IgM synthesis.•ERK inhibition attenuates NF- κB-triggered cytokine and immunoglobulin synthesis.•TLR-ERK-NF-κB axis regulates bacterial and PAMP stimulated IgZ and IgM expression. The molecular crosstalk of proximal innate immune receptor signaling mediated by Toll-like receptors (TLRs) is crucial in generating an adaptive immune response. The extracellular-signal regulated kinases (ERK) participate in propagating intracellular signals initiated by stimulated TLRs to transcription factors eliciting cytokine release. Although ERK signaling has been extensively studied in mammalian counterparts, very little is known about its existence in carps and its role in augmentation of immunoglobulin (Ig) synthesis. Therefore, to gain insights into the efficacy of MAP kinase cascade in orchestrating fish antigen receptor generation, Catla catla fingerlings were induced with various TLR agonists or pathogen associated molecular patterns (PAMPs). Analysis of upstream signaling events revealed that PAMPs stimulated the tissues leading to a significant upregulation (P