Research progress on the mollusc immunity in China

The economical and phylogenic importance of mollusc has led an increasing number of investigations giving emphasis to immune defense mechanism. This review discusses the advances in immunological study of mollusc in China, with special reference to dominant aquaculture species over the past decades. As an invertebrate group, molluscs lack adaptive immunity and consequently they have evolved sophisticated strategies of innate immunity for defense against pathogens. This review aims to present the various immunologically significant pattern recognition receptors (PRRs), such as Toll-like receptors (TLRs), lectins, lipopolysaccharide and β-1, 3-glucan binding protein (LGBP), scavenger receptors (SRs) employed by mollucans. This work also highlights immune proteolytic cascade, TLR signaling pathway and an extensive repertoire of immune effectors including antimicrobial peptide, lysozyme, antioxidant enzyme and heat shock protein. Further, the review presents the preliminary progress made on the catecholaminergic neuroendocrine system in scallop and its immunomodulation function to throw light into neuroendocrine-immune regulatory network in lower invertebrates.