Capsid Mosaics of Intermediate Strains of Human Adenoviruses

Antisera against isolated capsid components of intermediate adenovirus strains, types 3-16 (the San Carlos agent) and 15-9 and of "parental" prototype strains were compared in neutralization tests, hemagglutination-inhibition (HI) tests employing soluble and virion-associated hemagglutinin as antigens, and by electron microscopy. Hexons of the intermediate strains were found to be similar to, but not identical to, those of the prototype strains with which a cross-reaction occurred in neutralization tests (types 3 and 15). In contrast, fibers of intermediate strains displayed characteristics relating them to the corresponding components of prototype strains to which a relationship has been found in HI tests. Fibers (and possibly even pentons) of types 9 and 15-9 appeared to be identical, whereas fibers of types 3-16 and 16 displayed antigen specificities of both common and unique nature.