To determine the global gene transcriptional changes in channel catfish anterior kidney after immersion vaccination with attenuated Edwardsiella ictaluri compared to sham vaccinated catfsih control. The attenuated Edwardsiella ictaluri used for vaccination was Aquavac-ESC which was commercially available. Overall design: A six chip study using total RNA samples including 3 control and 3 vaccinated samples. Each RNA sample used for microarray was poold fish anterior kidney samples (5 fish anterior kidney samples were pooled as one). Each chip measrues the expression level of 65,182 genes. For each sequence, 3 probes were selected. Two copies were prepared on arrays.