A review of innate immunity of silkworm, Bombyx mori

Bombyx mori is an important economic insect for silk production. However, many kinds of pathogens cause serious economic loss every year during sericulture. B. mori lack an acquired immune system but have a sophisticated innate immune system against foreign microorganisms. The innate immunity system of B. mori is composed of humoral and cellular immune reactions, including production of antimicrobial peptides (AMPs), phenoloxidase, phagocytosis, nodule formation, encapsulation and melanization. Three immunity pathways had been reported in the B. mori to control the gene expression and defending invading microorganisms: Toll pathway, Imd pathway and JAK-STAT pathway. It has been shown that gene families associated with recognition, modulation and effectors are conserved from vertebrates to invertebrates. Recent accomplishment in molecular immunology of B. mori has been reviewed in this paper. The development of zinc-finger nuclease technique and silkworm genome information is expected to accelerate silkworm immunity studies.   Key words: Bombyx mori, innate immunity, signal pathway, pattern recognition receptors.