The relationship between the soluble antigens and the virion of adenovirus type 3: II. Identification and characterization of an incomplete hemagglutinin

Abstract

An incomplete hemagglutinin (HA), causing visible agglutination only in the presence of a heterotypic (type 11) adenovirus antiserum, was identified in preparations of soluble adenovirus type 3 components fractionated by zone centrifugation. The incomplete HA sedimented considerably more slowly than the complete HA and was recovered in the same region of the gradient as group-specific complement-fixing (hexon) antigen. Anion exchange chromatography resulted in the appearance of the three activities in separate peaks. The sequence of elution was hexon antigen, incomplete HA, and complete HA. Toxin activity accumulated mainly in the peak of incomplete HA, but some activity was also recovered in the peak of complete HA. Repeated absorptions of virus material with erythrocytes rapidly eliminated complete HA, whereas incomplete HA to a major extent remained unabsorbed. However absorption in the presence of an anti-adenovirus type 11 serum resulted in a disappearance also of incomplete HA as well as the toxin. An intimate relationship between complete and incomplete HA was evident from several experiments. The two HA's exhibited similar temperature requirements of agglutination, and absorption tests showed that they reacted with the same HI antibodies. Incubation at 52 ° for 1–3 hours of an eluate from erythrocytes, which was found to contain almost exclusively complete HA, led to a degradation into incomplete HA. It is postulated that the incomplete HA represents isolated penton antigens, i.e., vertex capsomers plus projections.