Get access

Lipopolysaccharide elicits expression of immune-related genes in the silkworm, Bombyx mori


Minoru Yamakawa, Innate Immunity Research Unit, National Institute of Agrobiological Sciences, 1-2 Owashi, Tsukuba, Ibaraki, 305-8634, Japan. Tel.: +81 29 838 6154; fax.: +81 29 838 6028; e-mail:


Lipopolysaccharide (LPS), a major cell wall component of Gram-negative bacteria, was found to be unable to activate immune-related genes in Drosophila melanogaster. In contrast, highly purified LPS elicited immune-related gene expression in the fat body of Bombyx mori. However, the level of activation by highly purified LPS was lower than crude LPS and peptidoglycan. Furthermore, synthetic lipid A also activated these genes, suggesting that B. mori possesses unknown signal pathways to activate immune-related genes by LPS. Up-regulation of antimicrobial peptide genes by highly purified LPS was not confirmed in the immune-responsive cell line, NIAS-Bm-aff3, suggesting that some factors necessary for signal transduction activated by LPS are deficient in this cell line.