Adenovirus type 12 surface antigen detected by immunofluorescence in infected KB cells

Close association of virus-specific cell surface and H-2 antigens in Ad12-infected and -transformed mouse cells

A virus-specific cell surface (S) antigen in adenovirus type 12 (Ad12)-transformed mouse cells has been assumed to be a direct target for cytotoxic thymus derived lymphocytes (CTL). In this study, the spatial proximity between the S and H-2 antigens was determined by three different methods, the proximity and co-capping tests, and the test for blocking of CTL-mediated lysis by anti-H-2 serum. In the proximity test with Ad12-infected thymic and splenic lymphocytes, and an Ad12-transformed line of C3H-He (H-2k) mouse cells, anti-H-2k and anti-S sera reciprocally inhibited fluorescent-antibody staining of the opposite antigens. By contrast, anti-Thy-1, 2 serum as well as anti-Ia and anti-Ig sera failed to show any appreciable effect in this test, when paired with anti-S serum. In addition, the S and H-2 antigens co-capped in the infected thymic lymphocytes, and CTL-mediated lysis of the transformed cells was abrogated equally by treatment of cells with anti-S and anti-H-2 sera. These results clearly demonstrate that there is a close proximity between the S and H-2 antigens on the surface of Ad12-infected and -transformed mouse cells.

Complement-dependent cytotoxicity in rats bearing human adenovirus type 12-induced primary retinoblastoma-like tumor in the eye

Using an animal model of retinoblastoma in inbred rats and cultured human adenovirus type 12-induced retinoblastoma-like tumor cells (RAO 188), complement-dependent cytotoxicity was determined by measuring release of 3H-uridine labelled RNA. Sera from rats in which tumors did not grow after adenovirus type 12 inoculation had higher cytotoxicity against RAO 188 cells than sera from rats bearing primary adenovirus type 12-induced retinoblastoma-like tumor. These results showed that the rat which could raise antibodies against adenovirus type 12-induced retinoblastoma-like tumor cells did not allow the tumor growth in the eye after virus inoculation.

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.

Surface antigens on HeLa cells persistently infected with HVJ (Sendai virus)

Surface antigens of HeLaHVJ cells, a cell line persistently infected with HVJ, were studied by fluorescent antibody staining. After absorption with concentrated HVJ virions and HeLa cells, anti-HeLaHVJ antiserum was able to demonstrate specific surface fluorescence on HeLaHVJ cells, while this serum no longer reacted with original HeLa cells nor with HVJ virions. During cytolytic infection of HeLa cells with HVJ, this specific surface antigen appeared at an early stage of infection prior to the appearance of newly synthesized HVJ viral antigens and moreover appeared in spite of the inhibition of viral protein synthesis. This antigen was detected neither on HeLa cells infected with other myxoviruses except HVJ nor on various other kinds of cells infected with HVJ. The specific surface antigen was still found on the HeLaHVJ cell surface after incubation at 38 degrees C for two days, while HVJ structural antigens on the cell surface no longer could be detected. Mild short-term treatment of HeLa cells with trypsin, neuraminidase from vibrio cholerae, phospholipase-C and hyaluronidase failed to expose specific antigen. The antigen was distinguishable from the Forssman and human blood type antigens. The mechanism of appearance of a new antigen on the surface of HeLaHVJ cells remains unclear.

Beta-glucuronidase response of cells infected with Adenovirus types 5 and 12

Beta-glucuronidase activity was investigated during a 48-h period in which virus replication and changes in cell morphology occurred. Infection of an established line of chimpanzee liver cells with either nononcogenic adenovirus 5 or highly oncogenic adenovirus 12 under one-step growth conditions produced differing patterns of enzyme activity. There was an increase in total activity and also enhanced leakage of beta-glucuronidase from cells infected with adenovirus 12. In contrast, the enzymatic pattern of cells infected with adenovirus 5 was similar to that of uninfected cells. Hydrocortisone prevented the abnormal release of beta-glucuronidase from adenovirus 12-infected cells. The compound had no effect on total enzyme activity or on virus replication and the development of cytopathology.