Type-specific opsonophagocytosis of group A Streptococcus by use of a rapid chemiluminescence assay.
A whole-blood chemiluminescence (CL) assay was developed to determine the presence of type-specific opsonic antibodies against group A streptococcus (GAS). Convalescent sera with high bactericidal activities against an M-1 serotype were used to opsonize different M-types of GAS. CL responses were monitored for 20 min, and results were expressed as integral counts/minute per phagocyte. CL responses of phagocytes incubated with M-1 GAS opsonized with homologous (M-1) serum were significantly higher than responses of phagocytes incubated with heterologous (M-3) GAS. Adsorption of convalescent serum against the homologous, but not the heterologous, strain markedly reduced the CL response, demonstrating type specificity. The CL assay showed a high correlation with the indirect bactericidal test (r=0.90). In conclusion, this CL assay is a rapid, highly sensitive, specific, and reproducible method for quantifying type-specific opsonic antibodies against GAS and will be a useful tool for future clinical, basic science, and epidemiological studies.
Villaseñor-S
A
A
Division of Infectious Diseases, Instituto Mexicano del Seguro Social, Guadalajara, Jalisco CP 45400, Mexico.
Bryant
A E
AE
Stevens
D L
DL
D001770:Blood Bactericidal Activity; D015169:Colony Count, Microbial; D006801:Humans; D008163:Luminescent Measurements; D009895:Opsonin Proteins / Q000097:blood*; D010587:Phagocytosis; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012703:Serotyping; D013290:Streptococcal Infections / Q000276:immunology*; D013297:Streptococcus pyogenes / Q000145:classification / Q000276:immunology*
D009895:Opsonin Proteins