Characterization of the 130kd Antigenic protein and Gene from Streptococcus agalactiae Cell Wall

• Main Author: 林悅予
• Other Authors: 邱卓凡
• Format: Others
• Language: zh-TW
• Published: 1999
• Online Access: http://ndltd.ncl.edu.tw/handle/17267775838124749055

碩士 === 國立臺灣大學 === 微生物學研究所 === 87 === Streptococcus agalactiae, GBS, is always the major cause of neonatal sepsis, pneumonia and meningitis. However, the cases of infection with GBS in adults have been increasing recently. In the meantime, GBS causes more kinds of diseases, such as puerpural fever, soft-tissue infection, and endocarditis, etc. The mechanism by which GBS causes disease is not well understood. To speed up the clinical diagnosis of GBS, therefore, a GBS specific gene of hippuricase was chosen to clone in this study. Surprisingly, a DNA fragment encoding for GBS surface protein was obtained. The DNA contained the sequence of the start codon and Shine-Dalgarno sequence. The result of genebank search was shown that the nucleotide sequence of the cloned DNA having 60% homology with sspB gene of Streptococcus gordonii, and the putative amino acid sequence of the cloned DNA having similarity with some streptococcal surface protein, such as Enn15, FcrA15 , Enn18, M5, and M25 of Streptococcus pyogenes, SspB of Streptococcus gordonii, Ssp5 of Streptococcus sanguis, and SpaA of Streptococcus sobrinus. By using rabbit immune-serum against GBS whole cell with indirect fluorescent antibody technique (IFA) and immunostaining assay, the transformed E.coli containing cloned GBS DNA did not demonstrate GBS protein on the surface in IFA study. However, a 130kD gene product same as GBS antigenic protein was detected from the cell lysate of the transformant by western blot and immunostaining assay. Therefore, the cloned DNA is a gene fragment of an antigenic GBS cell surface protein.