Detection of adenovirus by enzyme-linked immunosorbent assay

A solid-phase direct enzyme-linked immunosorbent assay (ELISA) was developed for the detection of adenovirus antigen in extracts of infected cells by using antihexon serum. Results with simulated clinical specimens consisting of normal nasal wash specimens seeded with varying concentrations of adenovirus type 5 showed that antigen could be detected in extracts of HEp-2 cell cultures inoculated with 10(2.5) 50% tissue culture infective doses (TCID50) and 10(1.5) TCID50 after 2 and 4 days of incubation, respectively. Fifty-three clinical nasal wash specimens containing adenovirus type 5 (stored for 5 years at -70 degrees C) were used to evaluate antigen detection by ELISA in HEp-2 cell extracts and by manifestation of cytopathic effect in human embryonic kidney cells. After 2 days of incubation, 62% were positive by ELISA, whereas none was positive for cytopathic effect. After 4 days of incubation, 76% were ELISA positive and 47% were positive for cytopathic effect. The results according to infectivity titers indicated that clinical specimens containing 10(3.0) TCID50 or greater were all positive by ELISA after 2 days of incubation in HEp-2 cells, and by 4 days all but one specimen containing 10(2.0) TCID50 or greater were ELISA positive. ELISA and immunofluorescent methods for antigen detection were compared using 24 of the 53 clinical specimens containing adenovirus type 5. Nearly equivalent sensitivities were demonstrated. These results suggest that ELISA may provide an alternative method of detecting and identifying adenoviral infections in humans.