Promotion of fibronectin independent invasion by C5a peptidase into epithelial cells in group A Streptococcus
Purushothaman, S.Sudha.; Park, H-Sun.; Cleary, P.Patrick.
Indian Journal of Medical Research 119(Suppl): 44-47
2004
ISSN/ISBN: 0019-5340 PMID: 15232161 Document Number: 581549
Background & objectives: Group A Streptococcus, causative agent of several clinical manifestations codes for multiple protein invasins which help the bacterium to enter non-phagocytic cells. C5a peptidase (SCPA) is a surface protein conserved among different serotypes of M1 strain. The present study was taken up to study SCPA promoted fibronectin independent entry of GAS into epithelial cells. Methods: An isogenic 90226 emm1DELTAAB (M1-) mutant was constructed, with thermosensitive pGhost vector. This isogenic M1- mutant expressed SCPA on the surface as determined by Western blotting and immunofluorescence. Results: On preincubation with anti-SCPA serum, the isogenic M1- strain exhibited 54 per cent decreased invasion as compared to the bacteria incubated with control serum. Also, purified recombinant SCPA proteins blocked internalization of M1- streptococci into HEp-2 cells. The M1- strain invaded at the same efficiency in the presence or absence of fibronectin. Interpretation & conclusion: These results suggested that SCPA acted as a potential invasin of group A streptococcus and promoted invasion independent of fibronectin.