Streptococcus Suis Serotype 2 Binding To Collagen

Streptococcus suis is one major swine pathogen that cause septicemia,meningitis,endocarditis and arthritis. Of the 35 known serotypes, serotype 2 is most frequently isolated and associated with diseases. One suspected case of streptococcus suis 2 was first reported in Guang dong province in 1990. A acute infectious septicemia of swine broke out in Jiangsu province in 1998-1999, and a certain people were infected, the pathogen is streptococcus suis 2, other than C group streptococcus suis. The original classification of S.suis 2 into Lancefield groups R. However, in China, most of researches focus on Streptococcus suis in group C,D,E and L .In order to preliminary establish one elisa of diagnostic kits, we prepared successfully the polyclonal antibody of whole bacterium, and detected the tite of antibody reach up to 1/512. We use the way of whole bacterium coat flat-bottom microtiter 96-well plates, establish the optimum concentration of bacterial coated in primary, condition of coat, blocking time, the optimum dilution of polyclonal antibody, the best dilution of horseradish peroxidase-labelled anti-rabbit IgG and the optimum reaction time etc. In a word, we set up the way of Elisa of diagnostic kits in primary.Binding of virulent bacteria to host cells is the first step in the colonization of mucosal. surfaces. Binding may also be a first step in the invasion of host cells, a process that may lead to bacteremia and sepsis .The pathogenesis of infections caused by S. suis is not fully understood and many steps are probably involved. S.suis is able to bind to invadeendothelial and epithelial cells of human and porcine origin. Since one hypothesis of the pathogenesis of S.suis infection is that bacteria enter the bloodstream and invade the meninges and other tissues in close association with mononuclear phagocytes, but bacterium can not be phagocyted completely. Therefore, adherence plays an important role in the pathogenesis function. However, the mechanisms involved in these interactions are unknown. Recently some scholars study the adherence between streptococcus suis 2 and vascular endothelial cell, tracheal epithelial cell,phagocytic cell.The test study the the ability of S.suis type 2 bind to collagen, one of extracellular matrix proteins(ECM), was evaluated by ELISA. Results indicate that the virulent strain bond to collagen is obviously higher than the weakly virulent strain(p<0.01). After the live bacterial suspension were primed by trypsogen, proteinase K and heat, the bacterial adhesion can be almost blocked (p<0.01). While cholesterol and galactose just partly block bacterial adhesion. The results suggest that the adhesins for these ECM proteins are proteinaceous in nature. Capsular polysaccharide may not participate in the adherent process, but the hemolysin participate in the process of bacterial adhesion. Anyway, the mechanism are waiting for our research in further.