Effect of the properties of enzyme-antibody conjugates on the quantitation of serum antibodies to Escherichia coli 02 antigen by the enzyme-linked immunosorbent assay, Elisa.
Immunoglobulins conjugated to horseradish peroxidase (HRP) or to alkaline phosphatase (AP) were compared for determinations of antibodies to Escherichia coli 02 antigen using the enzyme-linked immunosorbent assay (Elisa). AP-IgG conjugates had a higher avidity for their antigen than HRP-IgG conjugates. The avidity of AP-IgG conjugates was higher than that of the native IgG fraction from which it was derived, whereas HRP-IgG conjugates had the same avidity as the native IgG fraction. The Elisa method was more sensitive when performed with AP-IgG conjugates. However, differences in antibody titer between sera from convalescent and acutely ill patients with urinary tract infection caused by E. coli were detected with a higher degree of accuracy with the Elisa-HRP method than with the Elisa-AP method. The differences between Elisa-AP and Elisa-HRP are discussed in relation to the qualities of the conjugates.
D000042:Absorption; D000469:Alkaline Phosphatase; D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D001667:Binding, Competitive; D004797:Enzyme-Linked Immunosorbent Assay; D004926:Escherichia coli / Q000276:immunology*; D006735:Horseradish Peroxidase; D006801:Humans; D007136:Immunoglobulins; D010544:Peroxidases; D010655:Phenylenediamines / Q000494:pharmacology
D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D007136:Immunoglobulins; D010655:Phenylenediamines; D006735:Horseradish Peroxidase; D010544:Peroxidases; D000469:Alkaline Phosphatase