Of the ten CXC chemokines, two homologs of cxcl11, two of cxcl18, one of cxcl20 and one of cxcl8, also known as interleukin-8 (il8), were up-regulated in susceptible fish, whereas in resistant fish, three homologs of cxcl8/il8 were up-regulated in response to infection. This evidence concerns the gene CXCL8 and infection.