T and Tumour Antigens of Adenovirus Group C-infected and Transformed Cells

ONCOGENIC human adenoviruses are readily divisible into two chief subgroups: A (types 12, 18, 31), and B (types 3, 7, 14, 16, 21 and probably 11) based on similar biological and biophysical properties 1,2 . Recently, Freeman et al. 3 showed that adenovirus type 2, representative of a third subgroup of human adenoviruses, morphologically transformed rat embryo cells. The viruses of this subgroup, types 1, 2, 5 and 6, are similar in many biologic properties; they produce a partial haemagglutination pattern with rat erythrocytes, the agglutination being enhanced by the presence of heterotypic antibody 4 . Adenovirus type 4 also partially agglutinates rat cells, but in other respects, such as T antigen reactivity 5 , DNA–DNA homology 6 and homology with tumour cell m RNA 7 , seems related to the B oncogenic subgroup. The rat cells transformed with adenovirus 2 contain an antigen which reacted in both complement-fixation (CF) and immunofluorescent tests with sera from hamsters inoculated with tumour extracts and with cells transformed by adenovirus 1- and 2- SV 40 hybrid viruses 3,8 . These results suggested, as shown here, that other members of the adenovirus 1, 2, 5 and 6 subgroup would transform rat cells and that a common T antigen could be demonstrated. Evidence obtained by the fluorescent antibody method for a shared T antigen for adenoviruses 1 and 2 has already been reported 8 .