title: Immune response to group A streptococcal C5a peptidase in children: implications for vaccine development.
abstract: The group A streptococcal C5a peptidase (SCPA) is a major surface virulence protein that facilitates the establishment of local infection by group A streptococci (GAS). We measured the human immune response to SCPA, using a standardized indirect enzyme-linked immunosorbent assay. Paired acute and convalescent serum samples from children with GAS-associated pharyngitis were assayed, and a strong immune response to SCPA was demonstrated that was independent of the infecting M type and the age of the patient. Western blot analysis of bacterial extracts revealed that all tested M types expressed SCPA. The immune response to SCPA correlated with the anti-streptolysin O and anti-DNase B responses. These data confirm the immunogenicity of SCPA in humans. Previous knowledge of SPCA's role in virulence, its highly conserved nature, and the results of mouse protection studies make SCPA an ideal vaccine candidate for the prevention of GAS disease.
authors.affiliation: Department of Pediatrics, World Health Organization Collaborating Center for Reference and Research on Streptococci, Minneapolis, USA. shetx002@umn.edu
authors.forename: Anita
authors.initials: A
authors.lastname: Shet
authors.forename: Edward L
authors.initials: EL
authors.lastname: Kaplan
authors.forename: Dwight R
authors.initials: DR
authors.lastname: Johnson
authors.forename: P Patrick
authors.initials: PP
authors.lastname: Cleary
mesh_terms: D000208:Acute Disease; D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial / Q000097:blood*; D000918:Antibody Specificity; D001428:Bacterial Vaccines / Q000276:immunology*; D015153:Blotting, Western; D002648:Child; D002675:Child, Preschool; D015195:Drug Design; D010450:Endopeptidases / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D010612:Pharyngitis / Q000276:immunology / Q000517:prevention & control*; D011994:Recombinant Proteins / Q000276:immunology; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013290:Streptococcal Infections / Q000276:immunology / Q000517:prevention & control; D013297:Streptococcus pyogenes / Q000145:classification / Q000201:enzymology / Q000276:immunology* / Q000302:isolation & purification
chemical_list: D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D001428:Bacterial Vaccines; D007074:Immunoglobulin G; D011994:Recombinant Proteins; D010450:Endopeptidases; C053088:C5a peptidase