Learn More
Two methods for simple and rapid plating of single HeLa cells, human, carcinomatous cells, are described. These result in growth and formation of colonies from each single cell. One of these procedures uses irradiated, non-multiplying "feeder" cells to condition the medium. The second requires more gentle handling of the cells, but otherwise is virtually(More)
Naturally selected variants of influenza virus encoding truncated NS1 proteins were tested in chickens as candidate live-attenuated influenza vaccines. Their effectiveness correlated with the amount of interferon (IFN) induced in chicken cells. Effective variants induced large amounts of IFN and contained subpopulations with high ratios of(More)
The effects of x-irradiation have been quantitatively studied on single cells of a human cervical carcinoma (HeLa) under conditions such that 100 per cent of the unirradiated cells reproduce in isolation to form macroscopic colonies. This technique eliminates complexities due to interactions of members of large cell populations. Survival of single cells(More)
A gene encoding chicken interferon (ChIFN) was cloned from a cDNA library made from primary chick embryo cells that had been "aged" in vitro so as to produce copious amounts of IFN upon induction. The coding region is predicted to produce a signal peptide of 31 amino acids and a mature protein of 162 amino acids with a molecular weight of 18,957. There are(More)
The infectious particles of plaque-derived, low multiplicity passaged wild-type VSV of New Jersey origin consistently induce about 1800 units of interferon (IFN)/10(7) aged chick embryo cells. This inducing capacity is sensitive to both uv radiation and heat (50 degrees). Virus obtained after two successive high multiplicity passages in GMK-Vero cells(More)
Infectious bronchitis virus (IBV) causes an economically important respiratory disease in poultry worldwide. Previous studies have shown that CD8(+) cytotoxic T lymphocytes (CTL) are critical in controlling acute IBV infection, but the role of innate immunity is unknown. This study describes the in vitro and in vivo anti-IBV activity of natural spleen(More)