Anita Shet1, Edward Kaplan, Dwight Johnson, Patrick Paul Cleary. 1. Department of Pediatrics, World Health Organization Collaborating Center for Reference & Research on Streptococci, University of Minnesota Medical School, Minneapolis, MN 55455, USA. shetx002@umn.edu
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.
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: Vinzenz Lange; Johan A Malmström; John Didion; Nichole L King; Björn P Johansson; Juliane Schäfer; Jonathan Rameseder; Chee-Hong Wong; Eric W Deutsch; Mi-Youn Brusniak; Peter Bühlmann; Lars Björck; Bruno Domon; Ruedi Aebersold Journal: Mol Cell Proteomics Date: 2008-04-13 Impact factor: 5.911