Enzyme-linked immunosorbent assay for acute adenovirus infection

An enzyme-linked immunosorbent assay (ELISA) is described for demonstrating antibodies to the hexone antigen of adenoviruses. The antigen-coated, flat-bottomed microtiter plates are incubated sequentially with dilutions of patients' sera (2 h at 37°C) and peroxidase-coupled anti-human IgG (2 h at 37°C). After a final washing, orthophenylenediamine is added to the plates, and the absorbance ( A) measured 30 min later. The ELISA was found to be a hundred-fold more sensitive than complement fixation. An evaluation method for determining antibody concentration is described which correlates the absorbance of sera diluted 10 −3 to the absorbance of a reference serum containing an arbitrary value (100) of antibody. This method avoids titration of sera and day-to-day assay variations by different background reactions. A significant increase in antibody concentration of acute-phase serum over that of convalescent phase serum is observed. The ability to test sera in a single dilution and the automatic reading of results and their evaluation by computer make this assay suitable for diagnostic laboratories.