High Hemagglutinin Research Articles

The replication of the Kilham rat virus (RV) in various host systems: immunofluorescent studies.

The replicative cycle of the Kilham rat virus (RV-13) in rat embryo (RE), hamster embryo (HE), and L-929 cell cultures was studied under conditions of high viral input multiplicity. The synthesis of RV antigen in infected cells was followed by the indirect fluorescent antibody (FA) technique and correlated with the appearance of extracellular hemagglutinin. The synthesis of specific antigen in RE and HE cell cultures appeared to follow a similar pattern. Cytoplasmic fluorescence was observed early in the replicative cycle of RV in both host systems. Nuclear fluorescence was detected 6–8 h later after a decline in the number of cells exhibiting cytoplasmic fluorescence. Nuclear fluorescence appeared more extensive and more intense in RE cells. In addition, a significantly higher hemagglutinin titer was obtained from the infection of RE cells. The replicative cycle of RV in L-929 cells appeared aborted. Although the synthesis of RV structural antigen was detected in the cytoplasm of these cells, subsequent nuclear fluorescence was totally absent and extracellular hemagglutinin was not detected.

Enhancement of cytopathic effects of reoviruses in rolled cultures of rhesus kidney.

SummaryCytopathic effects of reoviruses in rhesus kidney tube cultures were markedly enhanced by incubation on a roller drum. Higher hemagglutinin and infectivity titers were attained after a shorter incubation period in rolled cultures, but the striking effect is in the increased cytocidal nature of reovirus replication under these conditions. Also, when cultivated in rolled monkey kidney culture tubes, infectious reovirus was still detected after incubation for 3-5 weeks at 37†C and after 45 minutes at 56†C.

Studies on the enzymatic properties of influenza viruses: I. The action of influenza B virus and RDE on the hemagglutinin inhibitor of human meconium

In purified preparations of human meconium, inhibitors of hemagglutination by influenza viruses have been described which are destroyed upon incubation with active virus. We have attempted to identify chemically the products liberated during such interaction. A solution of purified meconium of high hemagglutinin inhibitory titer (HAI) was incubated with strain Lee of influenza B virus. HAI was abolished overnight, no drop in HAI occurred in meconium solutions incubated with uninfected allantoic fluid or with virus previously rendered noninfective by heating at 56°. Dialyzates from meconium treated with active virus gave a violet color with Bial's orcinol reagent; dialyzates from control preparations were Bial-negative. From the Bial-positive dialyzates an acid was obtained in crystalline form which, on the basis of its X-ray powder diffraction diagram, melting point, optical rotation, and infrared spectrum was found to be identical with N-acetylneuraminic acid, as isolated by mild acid hydrolysis from the hemagglutinin inhibiting mucoproteins of sheep submaxillary mucin, human milk, and meconium. Thirteen per cent of the total neuraminic acid present in meconium was consistently liberated by the virus; a preparation of receptor-destroying enzyme (RDE) was more active and liberated as much as 48% of the neuraminic acid of meconium. In addition, dialyzates from virus or RDE-treated meconium contained a still unidentified ninhydrin-positive substance absent from control dialyzates.