Identification and expression profile of multiple genes in the anterior kidney of channel catfish induced by modified live Edwardsiella ictaluri vaccination.

Using PCR-select subtractive cDNA hybridization technique, 57 expressed sequence tags (ESTs) were isolated from 240 clones of a modified live Edwardsiella ictaluri vaccinated vs. sham-vaccinated channel catfish anterior kidney subtractive library. The transcription levels of the 57 ESTs in response to E. ictaluri vaccination were then evaluated by quantitative PCR (QPCR). Of the 57 ESTs, 43 were induced at least 2-fold higher in all three vaccinated fish compared to unvaccinated control fish. Of the 43 upregulated genes, five were consistently upregulated greater than 10-fold, including two highly upregulated (>20-fold) glycosyltransferase and Toll-like receptor 5. The transcriptional levels of GTPase 1, coatomer protein complex zeta 1, and type II arginine deiminase were consistently induced greater than 10-fold. MHC class I alpha chain and transposase were upregulated greater than 10-fold in two of the three vaccinated fish. The 43 upregulated genes also included 19 moderately upregulated (3-10-fold) and 17 slightly upregulated (2-3-fold). Our results suggest that subtractive cDNA hybridization and QPCR are powerful cost-effective techniques to identify differentially expressed genes in response to modified live E. ictaluri vaccination.