Terminal dilution purification of adenovirus prototypes, and the antigenic relationship between types 4, 16 and 14

Two terminal dilution purifications in HEK cells were performed with adenovirus prototypes of types 1 to 7, 12, 16, 19 and 9-15, and one terminal dilution with a freshly isolated type 8 strain. The antisera prepared against viruses after terminal dilution neutralized the original and the purified virus to the same extent, indicating the antigenic purity of the respective prototypes. Cross-reactions in neutralization with other types within the subgroup were also identical. Only the prototype of type 16 (Ch 79) showed a cross-neutralization with type 4, while four type 16 wild strains showed cross-neutralization with type 14, but none with type 4. The prototype (CH 79) is a "prime strain" in relation to the type 16 wild strains.