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We characterized the changes induced by treatment for 48 h with 100 U/ ml interferon gamma (IFN-gamma) on HeLa and CaSki cells, derived from human uterine carcinomas and containing human papillomavirus (HPV) type 16 and HPV type 18 respectively, by studying cell growth, cell morphology, the cell cycle and expression of epidermal growth factor (EGF) receptor, filaggrin-profilaggrin and MHC class II antigen, HLA-DR. The response of the two cell lines to IFN gamma differed in some cases. In both cell lines, the cells remained viable; cell growth was similarly inhibited as shown by cell counts. Signs of morphological changes were essentially observed in HeLa cells. The cell cycle phases, analyzed by flow cytometry were more disturbed in CaSki than in HeLa cells; the proportion of CaSki cells in S phase increased and those in G2 + M decreased. Expression of EGF receptors related to proliferation increased only in CaSki cells while expression of filaggrin-profilaggrin, a marker of differentiation, and HLA-DR, a marker of epithelial cell immune response, was enhanced in both cell lines. The presence of filaggrin-profilaggrin being unexpected in these cells, the specificity of the reaction with the monoclonal antibody AKH1 was confirmed by immunoblotting. In conclusion, our results show that the two cell lines reacted differently to IFN gamma although they are of similar origin and the different antigens studied may be useful to predict the progression of lesions infected with HPV towards malignancy or the reactivity to IFN gamma of such lesions. However, enhanced synthesis of EGF receptors is probably independent of the antiproliferative effect of IFN gamma but an increase in HLA-DR antigen expression by epithelial cells, which corresponds to an immune response favored by IFN gamma, could act synergistically with cell growth inhibition and differentiation to exclude tumoral and/or HPV-infected cells.

Six colonies producing antibodies were obtained by fusing mouse myeloma SP2-O cells with spleen cells from mice immunized with cytomegalovirus Davis strain. Among 88 surviving clones, 29 produced antibodies detectable by immunofluorescence on infected MRC5 cells and 2 others produced neutralizing antibodies against a homologous virus. Supernatants from these 31 positive clones and 4 others which were negative in immunofluorescence or neutralization were tested for their capacity to bind polypeptides from labelled Davis-infected cell extracts. Only 8 were found to be positive: five clones (A8, E3, F2, F8 and F20) precipitated 76 K, 60 K and 54 K bands; three others (A4, B9 and C24) precipitated 76 K and 54 K only. Surprisingly, these 8 monoclonal antibodies recognized a unique polypeptide 67 K of Towne-infected MRC5 cells. No correlation was found between (1) the pattern of fluorescence on MRC5 cells infected with Davis strain, (2) the neutralizing activity, and (3) the polypeptides recognized by the monoclonal antibodies.

Various parameters of the local cellular response have been studied in 16 laryngeal papillomas from ten patients with recurrent papillomas as well as normal control laryngeal and tracheal tissue by indirect immunofluorescence on frozen sections using monoclonal antibodies specific for T-cell subsets, Langerhans cells (LC) and HLA-DR antigens. Keratinization was investigated with a monoclonal antibody KL1 recognizing an acidic 56.5 Kd keratin, which is a marker of suprabasal cells in stratified squamous epithelium and is absent from the basal layer. The presence of viral antigen was detected with a rabbit antiserum raised against SDS-dissociated purified virus. A mild inflammatory response was observed in most biopsies. Cytotoxic/suppressor T-cells were the predominant cells found in the lesions. Compared with normal epithelium, the number of LC was dramatically reduced in the papillomatous epithelium. High densities of HLA-DR-positive cells were found mainly in the corium. The keratinization process was disturbed in most specimens in that both basal and suprabasal compartments reacted positively with the KL1 monoclonal antibody. Viral antigen was present in the nucleus of very occasional epithelial cells in some samples.

Two strains of cytomegalovirus (CMV) from patients with renal transplants and two other strains of CMV from young children were successfully propagated in human diploid cells, MRC5. Analysis by SDS-PAGE of these viruses passaged only 4 to 6 times revealed 21 to 29 polypeptides. The freshly isolated strains differed from reference strains, Ad 169 and Davis, in the number of bands, in the intensity of labeling of each band and also in molecular weight of the polypeptides. Some bands were common to all six strains. Some bands of molecular weight above 105 K were present in some strains and not in others. This was also the case for some bands between 64 and 76 K and two to five bands at low molecular weight between 17 and 22 K were detected. The band at 68 K was the most intensely labeled. Several polypeptides were precipitated by immune sera containing antibodies to CMV (one positive human serum and one guinea pig antiserum to Davis strain). Different bands were observed after precipitation, depending on the antiserum used and the strain of virus. Interstrain differences were found to be associated with antigenic heterogeneity. However, these cannot be correlated as yet with primary infection or reactivation.