HLA-C and infection: As a guideline for elucidating the biological response of viral/LPS-induced challenge, the comparison of differentially expressed genes by the GO categories showed a marked induction of metalloproteinases and other collagen and extracellular matrix sculptors in LPS treated trout, coupled with a decrease in genes controlling the basal metabolism and an increase in the activity of immune related mediators of MHC antigen presenting and immunoglublin-mediated opsonisation (figures 2 and 5) 72 h post infection.