Construction and analysis of subtractive hybridization library of differentially expressed genes in spleen of C57BL/6 and A/J mice with Streptococcus suis serotype 2 infection

Abstract

Streptococcus suis is an important swine and human pathogen, and it has presented a considerable challenge to the global public health community. Domínguez-Punaro et al. (2007) showed that two strains of mice were differentially susceptible to S. suis. The attainment of information on the differential expression of host response genes following S. suis infection is relevant to the understanding of the molecular mechanism of this disease. The intent of this study was to select and isolate differentially expressed genes from A/J and C57BL/6 mice that are associated with the host response to S. suis infection. These baseline data will allow for the screening and cloning of specific resistance genes, and further our understanding of the molecular mechanism of S. suis infection. Eightweek- old C57BL/6 and A/J mouse were infected with S. suis serotype 2, a 200-μL volume of a bacterial suspension (1 × 10⁸ CFU/mL) was administrated by intraperitoneal injection to the mice, and cDNA subtraction libraries were constructed by suppression subtraction hybridization (SSH). Genes involved in immune function, such as lysozyme, interferon-active protein, macrophage activation 2-like protein, complement component-3 and Ly108 protein were up-regulated in the spleen of C57BL/6 mice to a greater extent than they were in the spleen of A/J mice, subsequent to infection with S. suis serotype 2. Interestingly, we observed that several splenic signaling factors associated with phospholipid metabolism were up-regulated to a greater extent as well in C57BL/6 mice than they were in A/J mice following infection with S. suis serotype 2. These data suggest that phospholipid metabolism may be involved in the host defense response to S. suis invasion, thereby contributing to the organism’s overall immune response to this pathogen.

Key words: Streptococcus suis serotype 2, suppression, subtractive hybridization, differentially expressed genes, mouse spleen.