Changing Viral Susceptibility of a Human Cell Line in Continuous Cultivation

Section: Methodsmentioning

confidence: 99%

Adherence of Yersinia enterocolitica to Mammalian Epithelial Cell Lines

Okamoto¹,

Inoue

Ichikawa

et al. 1980

“…Hemagglutination (HA), neuraminidase (NA) assay, complement-fixation (CF) test and infectivity titration were described previously (12). Clone 1-5C-4 cells were grown in medium 199 containing 10% fetal calf serum (23).…”

Section: Methodsmentioning

confidence: 99%

Analysis of Nuclear Accumulation of Influenza NP Antigen in von Magnus Virus‐Infected Cells

Maeno

Aoki

Hamaguchi

et al. 1981

When 1-50-4 cells were infected with von Magnus virus derived from influenza AJRIJ5+ virus by four successive undiluted passages in chick embryos, virus-specific proteins were synthesized but production of infectious virus was inhibited. In these cells the synthesis of viral RNA was suppressed and the nucleoprotein (NP) antigen was found predominantly in the nucleus in contrast to standard virus-infected cells in which the antigen was distributed throughout the whole cell. The intracellular location and migration of NP were determined by isotope labeling and sucrose gradient centrifugation of subcellular fractions. In standard virus-infected cells NP polypeptide was present predominantly in the cytoplasm in the form of viral ribonucleoprotein (RNP) and intranuclear RNP was detected in reduced amounts. In contrast, in von Magnus virus-infected cells NP polypeptide was present predominantly in the nucleus in a non assembled, soluble form and the amount of cytoplasmic RNP was considerably reduced. After short-pulse labeling NP was detected exclusively in the cytoplasm in a soluble form and after a chase a large proportion of such soluble NP was seen in the nucleus. It is suggested that a large proportion of the NP synthesized in von Magnus virus-infected cells is not assembled into cytoplasmic RNP because of the lack of available RNA and the NP migrated into the nucleus and remained there.Canavanine, an arginine analog, is a potent inhibitor of the growth of influenza virus (11). It inhibits the synthesis of viral RNA and the formation of viral RNP.Under these conditions, most of the NP is found in the nucleus in a nonassembled, soluble form, in contrast to untreated cells in which a large amount of NP is distributed in the cytoplasm in the form of RNP. Influenza RNP consists of multiple molecules ofNP and one segment of virion RNA (vRNA) or cRNA complementary to vRNA (2, 17). We have suggested the possibility that the NP synthesized in the presence of canavanine is not assembled into cytoplasmic RNP because of the lack of available RNA and that the NP readily migrates into the nucleus and ac-1 Present address: Gamagori-Fukashi Hospital, Gamagori, Aichi 433. 283

“…Continuous lines of L, BHK and clone 1-5C-4 cells (25,27) grown in medium 199 supplemented with 10% fetal calf serum were used. Medium 199 without serum was used as a maintenance medium.…”

Section: Methodsmentioning

confidence: 99%

Intracellular Development of Membrane Protein of Influenza Virus

Maeno

Yoshii

Yoshida

et al. 1977

The intracellular development of membrane protein (MP) of influenza A virus was investigated by immunofluorescent staining. Monospecific antiserum was prepared by immunizing rabbits with MP eluted from SDS-polyacrylamide gels of SDS-disrupted NWS virions. In the productive infection in clone 1-5C-4 cells, MP antigen was first detected over the whole cell at 4 hr after infection, concomitantly with the appearance of hemagglutinin (HA) antigen in the cytoplasm, and bright nuclear fluorescence was then observed. Nucleoprotein (NP) antigen was detected in the nucleus prior to the appearance of fluorescence of MP antigen and thereafter the cytoplasmic fluorescence developed. Late in infection, all of these three antigens were observed predominantly in the cytoplasm with stronger fluorescence at the cell surface. Essentially similar findings were obtained in the abortive infections in L cells and BHK cells.The above results suggest that the membrane protein of influenza A virus is present in the nucleus as well as in the cytoplasm of infected cells.