Comparative studies on the soluble components of adenovirus types 9 and 15 and the intermediate strain 9-15.

Five different soluble components of adenovirus types 9, 9-15, and 15 have been identified. These are: (i) a slowly sedimenting, trypsin-resistant, incomplete hemagglutinin (HA). (This component was demonstrable by hemagglutination-enhancement (HE) tests in the presence of heterotypic antisera against members of Rosen's subgroups II and III, but not of subgroup I); (ii) a slowly sedimenting, trypsin-resistant, complete HA, causing only a partial agglutination of cells; (iii) a rapidly sedimenting, incomplete HA, demonstrable by HE tests in the presence of heterotypic antisera against members of all Rosen's subgroups. (Trypsin treatment of this component caused a conversion into slowly sedimenting incomplete HA); (iv) a group-specific complement-fixing (CF) antigen devoid of HA activity; and (v) a rapidly sedimenting, trypsin-sensitive, complete HA, which in the electron microscope was found to represent a dodecahedral aggregate of 12 pentons (a dodecon). On the basis of their biological and physicochemical characteristics, the first four components were interpreted to represent (i) fibers, (ii) a polymer of a few, probably two, fibers, (iii) pentons, and (iv) hexons, respectively. The length of fibers extending from dodecons and virions was estimated to be 11 to 14 nm. A similar value was suggested from exclusion chromatography experiments. Adenovirus types 9 and 15 fibers were recovered in a position intermediate to that of fibers of types 3 and 4, the lengths of which are 10 and 17 nm, respectively. The sequence of elution of different components of types 9 and 9-15 from an anion exchanger was fibers, fiber-aggregate, pentons, hexons, and dodecons. Type 15 components appeared in the same order except for the fact that dodecons eluted before hexons. The molarities of NaCl required to elute the different types 9 and 9-15 components, excluding hexons, were identical. They were distinctly different from those of the corresponding type 15 components. However, hexons of all three serotypes eluted in proximity to each other and there was a slight tendency for type 9-15 hexons to take a position intermediate to those of types 9 and 15.