Abstract: The cascade of innate immunity in organisms was regulate d by a set of genes. The gene immune deficiency of Drosophila plays an important role in the pathway of humoral immunity. We got a homolog of Drosophila imd from Bombyx mori successfully through silico cloning, and named it Bmimd. The gene is 1 092 bp in length, consisting of 4 exons and 3 introns, containing an ORF of 750 bp, encoding a protein with 250 amino acids, and the predicted molecular weight is 28.6 kD. Bmimd contains a death domain, which is similar to mammalian RIP by sequence analysis. Prokaryotic expression of the gen e recombinant with six-His tag and a Nus·Tag was successfully carried out through sub-cloning into PET-50b vector. The result of Western blotting showed that the gene was expressed in head, fat body, germen, cuticle and midgut, but its ex pression was not detected in silk glands of the silkworm.

Key words: Bombyx mori, imd, cloning, expression, innate immunity