Pentraxin family members of largemouth bass (Micropterus salmoides): Cloning, characterization and expression responses to LPS, Poly (I:C) and Nocardia seriolae.

Pentraxins (PTXs) are highly conserved soluble pattern recognition molecules, and play important roles in the innate immunity and autoimmune diseases. In present study, ten PTXs including CRP1, SAP, NPTX1-like, NPTX2a, NPTX2b, NPTXR-like, NPTXRb, PTX3a, PTX3-like and PTX4 were identified from largemouth bass (Micropterus salmoides). These PTXs exhibited high sequence identities with their counterparts of other fish species, and contained conserved motifs and structures of the PTX family, except of PTX3-like. Phylogenetic analysis revealed that these largemouth bass PTXs were closely clustered with their counterparts of other fish species, confirming the correctness of the obtained sequences. Realtime qPCR analysis showed that these PTX genes were widely expressed in all examined tissues, and lipopolysaccharide (LPS), Poly (I:C), and Nocardia seriolae stimulation significantly induced their expressions in head kidney (HK), spleen, gill, and intestine. These results demonstrated the crucial roles of PTXs members in the immune response of largemouth bass against pathogen invasion. To the best of our knowledge, this study represents the first identification of NPTX1, NPTX2b, NPTXRa, NPTXRb, and PTX4 in fish species, as well as the initial documentation of PTXs in largemouth bass.