A Viral growth enhancing factor (enhancer) was produced in the chorioallantoic membranes of eggs infected with influenza virus (PR8) and was released into the allantoic fluids. Enhancer was detected by its activity to enhance HA production by HVJ in roller tube cultures of shell-membrane pieces. The enhancement of HA production was obtained either by preincubation of the cultures with enhancer at 37°C for 24hours before challenge of HVJ, or by its addition into the cultures simultaneously with challenge.
The production and release of enhancer occurred in the early stages of infection with PR8 virus, Enhancer activity of the allantoic fluid and chorioallantoic membranes declined rapidly after 24hours of infection and was followed by the appearance of interferon activity. The time when enhancer activity was increasing and maintained a high level corresponds with the time when virus was growing approximately at a linear slope. Interferon activity first appeared in the chorioallantoic membranes and allantoic fluids at 36hours after infection with PR8 virus, when virus growth had reached a maximal level. Subsequent rise in interferon titers was associated with decline of cellular virus titers.
Interferon blocked enhancer activity when added to cultures of shell-membrane pieces before or after the enhancer, as well as when added at the same time as enhancer. Alternatively, enhancer blocked to some extent interferon activity when added before or after the interferon, as well as when added at the same time as interferon.

抄録全体を表示

感染細胞の核について, 光学顕微鏡的封入体と電子顕微鏡的ウイルス粒子存在部位との相互係を観察し, さらにネガテイブ染色法を行なつてビリオンの構造を観察した. ウイルス感染初期の細胞では, 核内にエオジン好性で電子密度の高い物質が分散してみられ, その付近にはウイルスの結晶状配列が認められた. さらに感染が進めば, 核内周辺部からしだいに中心に向つて透過性を示すようになり, 中心部は紫赤色濃染性の封入体をみるようになつた. この透過性部分には不規則散在性のウイルス粒子を多数認めた. 濃染封入体部分は結晶状配列ウイルス粒子, 核物身, 電子密度の高い物質, 代謝産物と思われるエオジン好性で電子密度高く無構造辺縁円滑な顆粒の混在からなる. 感染末期の核は全体が透過性となり, ウイルス粒子群と代謝産物様顆粒のみが存在していた.
ビリオンの形態については, 切片像では限界膜と芯とが区別され, ネガテイブ染色像では正二十面体を示す.

抄録全体を表示