Antibody to human adenovirus early antigens during acute adenovirus infections

The antibody (Ab) response to human adenovirus (AV) early antigens (EA) in acute AV infections was studied by the immunoperoxidase antibody technique for determining virus-specific immunoglobulin G (IPA-IgG). AV-EA-Ab appeared about 5 days after the onset of clinical symptoms, reached a peak 15 to 30 days later, and declined in titer after a few months. The staining pattern in the IPA-IgG reaction was usually nuclear; however, in most primary infections sera obtained 2 to 3 weeks after the onset of infection also showed cytoplasmic staining. According to the recent deoxyribonucleic acid homology classification of human AV in five groups (A, B, C, D, and E), the EA-Ab response in primary human infections was found to be group specific for groups A to D, with consistent cross-reactions with group E. In AV type 4 (group E) infections, EA-Ab appeared to be directed against all groups, although at different titers. Comparable results were obtained using AV type-specific animal antisera. Thus, it was concluded that group E shares EA with all the other groups. Furthermore, in each individual with remote AV infections, the current infection elicited an anamnestic EA-Ab response to all AV groups responsible for previous infections. In diagnostic virology these findings can be applied to the rapid diagnosis of a current (or recent) AV infection on a single serum sample and to the rapid group identification of clinical isolates by using type-specific animal antisera containing EA-Ab (one for each group) or sera from patients with primary AV infections.