ABSTRACT
Ninety-seven adenoid vegetations (AV) originating from children aged 2 to 11 years were examined for the presence of adenoviruses. No infectious virus was detected in cell-free homogenates. However, adenovirus was recovered in 30 instances from either fragment or trypsinized cell cultures, or both, of the same tissues. The viruses belonged to types 1, 2, 5 and 6. It was determined by the infectious center assay that the frequency of virus-producing cells in different AV varied between 1 of every 10(5) cells to 1 of every 10(7) cells. Cells reactive with hamster sera containing antibody against the adenovirus early ("T") antigen and with rabbit sera containing antibody against the virus structural antigens were detected in cell smears from trypsinized virus-positive AV. The frequency of positive cells was very low. Nearly 80 per cent of extracts from virus-positive AV contained substances neutralizing the homotypic viruses. Adenovirus-neutralizing substances were only rarely detected in extracts from virus-negative AV. The neutralizing substances could be removed from the extracts by absorbtion with concentrates of the homotypic viruses. Most of the subjects from whom AV containing neutralizing substances were obtained, possessed high levels of homotypic serum antibodies.