Comparative study by immunofluorescence of T and P antigens induced by adenovirus type 12 in permissive and nonpermissive cells

The development of adenovirus type 12 T antigen and of the complex of antigenic early proteins designated as P antigen was studied by immunofluorescence in productively infected KB cells and abortively infected RK-13 cells. T antigen is detected in both cell types very early in infection. In KB cells it presents the well known pattern of nuclear dots and flecks but in RK-13 cells at the time of maximum abundance, 18 hours p.i., T antigen forms a net of long filaments that fills the nucleus. Later, part of the filaments condense into a large aggregate that finally is apparently degraded. P antigen in infected RK-13 cells looks like T antigen in KB cells. In these cells, besides an early phase wherein P antigen is almost indistinguishable from T antigen, a late component is evident under the form of large balls and rosettes. The possible identification of this component with the DNA binding protein is discussed.