Archives of Virology

Schiff, L. J.

doi: 10.1007/bf01240607pmid: 4209454

SummaryTracheal organ cultures of 4-day-old, 2-, and 4-week-old Syrian hamsters infected with influenza A/PR/8 virus were studied. Ciliary activity in infected explants from 4-day-old and 2-week-old hamsters declined rapidly after five days and by the 13th day was virtually undetectable. Cultures from 4-week-old hamsters showed a similar but slower effect. Histological sections of infected explants showed distinct cytopathologic changes which preceded ciliostasis. The columnar structure of the ciliated respiratory epithelium in all infected tracheal tissue became flattened and was eventually destroyed. When influenza A/PR/8 virus was added to whole tracheal explants from 4-day-old hamsters, approximately 70 per cent of the virus adsorbed in the first 30 minutes, and 90 per cent of the total adsorbed within 2 hours. Explants from 2- and 4-week-old hamsters adsorbed influenza virus at a much slower rate. Growth curves indicated that tracheal cultures from all three age groups support replication of A/PR/8 virus. Explants from 4-day-old hamsters yielded a maximum titer of 103.75HAD50/ml by the 9th day after injection; cultures from 2- and 4-week-old hamsters yielded a 5 and 15-fold lower infectivity titer. Interferon was demonstrated in infected cultures from the three different age groups in comparable concentrations.In vivo studies indicate that 4-day-old hamsters have a greater susceptibility than 2- and 4-week-old hamsters to hamsters-adapted influenza A/PR/8 virus. Observations from cultures of young suckling hamster tracheas indicate this model system will be useful in further investigations of tissue specificity in influenza viral infections.

Lomniczi, B.

doi: 10.1007/bf01240608pmid: 4837359

SummaryThe avirulent strain KF of Aujeszky's disease (pseudorabies) virus had a 10 to 100 times lower growth ability in chick embryo fibroblast cells than the virulent strain and it formed scarcely visible plaques, if any. Infection of permanent pig kidney cells (PK15) with avirulent strains resulted in higher virus yields than the virulent strain and easily visible, small plaques (0.5 mm) arose. The virulent strain formed plaques about 2 mm in diameter in both types of cells. The avirulent strains were not neuropathogenic for the chick, whereas the virulent strains showed a distinct neurovirulence. The avirulent strains stimulate a small amount of interferon in chick embryo fibroblast cultures from about 30 hours after infection and are 5–10 times more sensitive to interferon than the virulent strains.

Hara, K.; Beare, A. S.; Tyrrell, D. A. J.

doi: 10.1007/bf01240610pmid: 4857907

SummaryA study was made of human influenza A viruses and of recombinants in ring organ cultures of human and ferret tracheas. All these viruses had previously been given to man and their virulence defined by clinical observation. There was an apparent association between the ability to reduce ciliary activity and the ability to produce human disease. This association was more evident in the human organ cultures than in the ferret organ cultures. Attempts to relate virus growth in organ cultures to human virulence gave ambiguous results.Of 4 sets of recombinants examined, ciliary damage agreed well with virulence in 1 set, less well in 2 others and not at all in a 4th. Measurement of ciliary movement on the 10th day and titration of virus in the culture medium on the 5th day seemed to suffice for the differentiation of viruses in this system. The technique was not a general test of virulence, and 3 influenza B viruses of differing virulence for man all stopped the beating of cilia in human tracheal organ cultures in 3–5 days.It is suggested that the technique be studied further by genetic methods.

Schmidt, W. A. K.; Klein, Magdalena

doi: 10.1007/bf01240613pmid: N/A

ZusammenfassungEin Latex-Agglutinations-Hemmtest wird beschrieben, der zum Nachweis von Antikärpern gegen Enteroviren geeignet ist. Mit γ-Globulin aus Anti-Polio-, Anti-Coxsackie- und Anti-Echo-Hyperimmunseren beladene Latexpartikel dienten dabei als Indikatorsystem. Der Test ist spezifisch, empfindlich und liefert reproduzierbare Ergebnisse.