Promotion of fibronectin independent invasion by C5a peptidase into epithelial cells in group A Streptococcus.
OBJECTIVE
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.


CONCLUSIONS
These results suggested that SCPA acted as a potential invasin of group A streptococcus and promoted invasion independent of fibronectin.
Purushothaman
Sai Sudha
SS
Department of Microbiology, University of Minnesota, MN 55455, USA. psai98@yahoo.com
Park
Hae-Sun
HS
Cleary
P Patrick
PP
D018829:Adhesins, Bacterial / Q000378:metabolism*; D015153:Blotting, Western; D002460:Cell Line; D010450:Endopeptidases / Q000378:metabolism*; D004847:Epithelial Cells / Q000382:microbiology*; D005353:Fibronectins / Q000502:physiology*; D006801:Humans; D013297:Streptococcus pyogenes / Q000502:physiology*
D018829:Adhesins, Bacterial; D005353:Fibronectins; D010450:Endopeptidases; C053088:C5a peptidase