Human immunogenicity studies on group A streptococcal C5a peptidase (SCPA) as a potential vaccine against group A streptococcal infections.

Abstract

BACKGROUND & OBJECTIVES:

Group A streptococcal C5a peptidase (SCPA) is a major virulence surface factor. Its highly conserved nature among all tested serotypes of group A streptococci (GAS) as well as animal protection studies make SCPA a prime vaccine candidate. The present study was undertaken to explore the human immunogenicity to SCPA using an indirect enzyme-linked immunosorbent assay.

METHODS:

Children (n=72) who had signs and symptoms of acute pharyngitis and had GAS isolated from the throat at initial visit were included. Acute and convalescent sera were collected 4 weeks apart. ELISA was performed using recombinant SCPA peptide as antigen.

RESULTS:

The mean convalescent anti-SCPA level was twice the level of mean acute anti-SCPA and the difference was statistically significant (P < 0.0001). There was a rise in convalescent anti-SCPA in all children aged 2-12 yr.

INTERPRETATION & CONCLUSION:

Our observations confirmed that SCPA was highly immunogenic in children infected with group A streptococcal pharyngitis. Further studies need to be done to characterize the immune response including antibody subclass.

• Authors: Anita Shet, Edward Kaplan, Dwight Johnson, Patrick Paul Cleary
• Journal: The Indian journal of medical research (Indian J Med Res) Vol. 119 Suppl Pg. 95-8 (May 2004) ISSN: 0971-5916 [Print] India
• PMID: 15232171 (Publication Type: Journal Article)

Chemical References

• Adhesins, Bacterial
• Endopeptidases
• C5a peptidase

Topics

• Adhesins, Bacterial (metabolism)
• Child
• Child, Preschool
• Endopeptidases (metabolism)
• Enzyme-Linked Immunosorbent Assay
• Humans
• Streptococcal Infections (immunology, prevention & control)
• Streptococcus pyogenes (enzymology)