Detection Of Glyceraldehyde Phosphate Dehydrogenase Gene Of Streptococcus Suis Type 2 And Its Adhesin Activity

A pair of primer was synthesized based on the published Streptococcus suis type 2(SS2) glyceraldehyde-3-phosphate dehydrogenase gene (gapdh) and PCR was applied to detect 39 streptococcal strains including SS2 .The gapdh was found in all tested strains, but not in SS2 T15. The gapdh of HA9801 ZY05719 and SS2-D were sequenced and logged in GenBank. The gapdh of the above three strains were analysised by BLAST and DNAStar with published SS2 gapdh in GenBank. The homology of them was 99.9%, 99.8% and 99.7%. GAPDH gene was ubiquitous in Streptococci.The gapdh of SS2 Sichuan isolation ZY05719 was cloned by PCR and inserted in prepared vector pET-32 a (+).The recombined vector pET-32a-GAPDH was introduced in E. coli BL21.A 58 kD GAPDH protein was expressed and purified by His·Bind~R Purification Kit (70239-3).An adherence assay with SS2 and HEp-2 cells pre-incubated with purified GAPDH and non-incubated cells was showed a significant reduction in the adhesion of SS2 in the purified GAPDH pre-incubated cells compared to the non-incubated cells. The GAPDH protein of SS2 seems to be involved in the bacterial adhesion to host cells.The aim of the study was to certify whether the extracellaluar proteases of Streptococcus suis 2 type (SS2) Jiangsu isolation could enhance the infection ability of H3N2 Swine Influenza virus (SIV) A/Swine/Guangdong/4/2003, based on the hypothesis that extracellaluar proteases produced by SS2 can cleave the hemagglutinin(HA) of SIV. MDCK cells were used for study model. CPE, haemagglutination litre of cell culture supernatants and immunoflourescence intensity of the cells were all enhanced when the extracellaluar proteases of SS2 existed .