Pathogen-associated gene expression profiles in rainbow trout macrophages

Pathogens can be distinctively recognized by the cells of the immune system through interactions between the Pathogen-Associated Molecular Patterns (PAMPs) that they produce and the innate immune receptors of leukocytes. The present paper reports on the PAMP-modulated expression of a group of genes expressed in trout macrophages. The genes were identified in subtracted libraries from lipopolysaccharide (LPS)-stimulated macrophages and their expression was analyzed using quantitative real time PCR following stimulation of the cells with E. coli LPS, poly (I:C) and zymosan; representing Gram-negative bacteria, viruses and fungi, respectively. Genes (SPINT1L, DDIT4L, STEAP4, and TNFAIP3), the expression of which was induced by LPS and zymosan, were not significantly up-regulated by poly(I:C) and the opposite was found for transcripts (HMGB1 and PSMB9) up-regulated by poly(I:C). Overall, the differences in gene expression were greater at a later stage of macrophage activation (24 h) at a time when stimulation with poly(I:C) resulted in substantially different responses as compared to LPS and, to a lesser extent, zymosan.