Streptococcus suis 2 (SS2) is an important zoonotic agent, and its pathogenesis has been extensively studied recently. Our earlier study showed that there were different responses between pig breeds after SS2 infection, which is similar to the previous observation in two mice lines. Bases on our previous transcriptome sequencing profiles, 15 target genes in spleen, lymph node, brain, lung, and liver were compared between Enshi black and Landrace breeds after SS2 infection, by qPCR in this study. Gene Resistin was up-regulated in lymph and spleen of both breeds, whereas it was significantly down-regulated in lung and liver of Enshi black. IL-1b and CD300c was significantly up-regulated in the brain and lymph of Enshi black and the liver of Landrace, whereas CXCL10 was significantly up-regulated in the brain and liver of Enshi black, and the lymph of Landrace pig. Gene NPG3 was highly induced in the brain and lymph of Enshi black, but not so high in Landrace. S100A8, S100A9 and S100A12 were significantly increased in the brain of Enshi black but S100A9 was significantly decreased in the lymph node of Enshi. MMP9 in the brain was up-regulated in Enshi black whereas it was down-regulated in Landrace. We observed differential performances from 5 immunoglobulin genes, especially IGLV5 and IGKV6. Our results suggested that Enshi black and Landrace have significant differences of innate and adaptive immune responses after SS2 infection. The results could lay foundation for further deep study of resistance/ susceptibility mechanism in pigs.

Key words: Enshi black and Landrace pigs, Gene expression, Immune response Streptococcus suis