Development Of Vaccines Against Swine Streptococcosis

Nineteen isolates were obtained from diseased pigs in Shanghai area from 1997 to 2000 and the characterized isolates of nineteen belonged to genus Streptococcus. The four could be agglutinated by the antisrum of Step. suis type 2,and the eight could be agglutinated by the lancefild group A桮 latex diagnostic kit. It demonstrated that the pathogen of swine streptcoccosts in the shanghai area at present Were either the memher of lancefield C group or the group R, 1. e. Srep. stiis type 2.Before development of inactivated combined vaccine, Streptococcus equi suhsp. zooepidernicus and Strep. suis type 2 were selected from isolates . ATCC35246 and HA9801 were selected for high梫irulent and good梚mmunity. To optimization the culture conditions, different mediums and culture ways were compared.To detecte protective efficacy of vaccine against swine Streptoccosis, a piglet model infected Strep. siiis type 2 was established.An killed whole-cell hacterin was prepared with Streptococcus equz suhsp. zooepidernicus ATCC35246 and Strep. suis type 2 IIAYSOI . Piglet were inoculated i. m. with 2.1 per piglet at 28梔ay梠]d. The protective efficacy of Strep. suis type 2 reached l0t~6(l0/10) and Strep. equ subsp. zooepidernicus reached 90%(9/l0) post challenge with the virulent strains on the day 15 after the vaccine was inoculated. These results showed that the inactivated vaccine was able to provide an protection against Strep. suis type 2 and Si rep. ~ui subsp.76Abstractzooep.idemicus.An indirect ELISA was established for detecting antibodies of inactivate combined vaccine of swine Streptococcosis. The ELISA was of high specificity and its sensitivity was 200 times than AGD. Three adjutants ,alumiumn hydroxide gel, propalis and oil were compared.Previous studies had indicataed that M條ike protein of Streptococcus equi .subsp. zooepidemicus is an important virulence factor and protective antigen. The M梡rotein was extracted by hot梐cid ways, and partially purified by hydroxyapatite (HAT) chromatography and cold梐lcohol precipitate. The whole cell bacterin, the acid梕xtracted protein and partially purified M條ike protein were used to vaccinate mice. The protective efficacy were 83. 3%(1O/12),92%(ll/12), 100%(12/12)respectively. It suggest that the M條ike Protein could be developed a usful Vaccine against the infection Streptococcus equi subsp. Zooepidemicus.