Abstract |
Crossreactions between bacteria occurring more or less frequently in the respiratory tract were investigated using an enzyme-linked immunosorbent assay (ELISA) developed for the detection of pneumococcal C-polysaccharide. A collection of 218 strains was investigated: 30 Streptococcus pneumoniae, 120 alpha-streptococci, and 68 strains representing other species. Strong crossreactions were observed with 36% of the alpha-streptococci and with two of 11 Staphylococcus aureus strains. The collection of alpha-streptococci consisted of 90 fresh clinical isolates and 30 stock strains. Almost all crossreactions of alpha-streptococci were found among the clinical isolates. Among the stock strains only one of four Streptococcus mitis strains was positive. Pneumococcal C-polysaccharide and phosphorylcholine inhibited the reactions in ELISA with monoclonal antibodies against pneumococcal C-polysaccharide, as well as with a polyclonal antiserum against pneumococcal C-polysaccharide. We suggest that the cross reactions between alpha-streptococci and pneumococci depend on the presence of phosphorylcholine as a common antigenic determinant. The crossreaction in the ELISA with some Staphylococcus aureus strains may be explained by the presence of protein A binding to the Fc portion of the antibodies. When the 10 alpha-streptococci that showed the strongest crossreactions and ten pneumococci representing different types were tested in different concentrations the absorbance values were lower for most alpha-streptococci compared with the pneumococci. This explains that false positive results with alpha-streptococci do not seem to constitute a practical problem in this ELISA developed for detection of pneumococcal C-polysaccharide in samples from patients with pneumonia.
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Authors | A M Sjögren, H Holmberg, A Krook |
Journal | Diagnostic microbiology and infectious disease
(Diagn Microbiol Infect Dis)
Vol. 6
Issue 3
Pg. 239-48
(Mar 1987)
ISSN: 0732-8893 [Print] United States |
PMID | 3568596
(Publication Type: Journal Article)
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Chemical References |
- Antigens, Bacterial
- Polysaccharides, Bacterial
- polysaccharide C-substance (Streptococcus)
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Topics |
- Antigens, Bacterial
(analysis, immunology)
- Cross Reactions
- Enzyme-Linked Immunosorbent Assay
- Humans
- Pneumonia, Pneumococcal
(diagnosis)
- Polysaccharides, Bacterial
(immunology)
- Staphylococcus aureus
(immunology)
- Streptococcus
(immunology)
- Streptococcus pneumoniae
(immunology)
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