PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Serial Passage”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1984

Selection of attenuated dengue 4 viruses by serial passage in primary kidney cells. I. Attributes of uncloned virus at different passage levels.

Attempts were made to attenuate prototype dengue (DEN) 4 (H-241) virus. The original viremic human serum was passed once in a susceptible monkey and twice in Aedes albopictus mosquitoes and then serially passed in primary dog kidney (PDK) and African green monkey kidney (GMK) cells. Weekly transfers of undiluted virus were carried to the 50th passage in both primary cell cultures. Biological markers were studied at passages 7, 15, 30 and 50. Parental DEN-4 phenotype characteristics included large plaque formation in LLC-MK2 cells, plaque formation in GMK cells, cytopathic effect in LLC-MK2 cells, growth in human monocyte cultures, growth at 39 degrees C, consistent production of viremia in monkeys and short-incubation neurovirulence in mice. At the seventh passage in both PDK and GMK cell cultures, DEN-4 viruses exhibited reduced plaque-size in LLC-MK2, and failed to plaque in GMK, to produce cytopathic effect in LLC-MK2, or to grow in human monocytes. Serial passage in PDK, as opposed to GMK, resulted in a graduated loss of monkey virulence. Rhesus monkeys inoculated with the PDK 50 strain failed to develop detectable viremia and only 1 of 4 developed an antibody response. Also, replication of PDK 50 was completely shut-off at 39 degrees C. The graduated change in biological properties noted, particularly those in PDK cells, provide a range of potential vaccine candidates for evaluation in human beings.

Aedes↗
PubMed1951

Studies on host-virus interactions in the chick embryo-influenza virus system. V. Simultaneous serial passage of the agents of influenza A and B in relation to variations in the growth cycle of influenza B virus.

The combined passage of influenza A and B viruses in series, as reported by Sugg and Magill, has been confirmed. When the mixed passage materials were not too highly diluted both agents could be traced through 10 transfers. Growth curve experiments revealed that both agents developed independently, as measured by hemagglutination-inhibition tests in the presence of specific immune sera against one or the other type. However, the hemagglutinin titers of the 2 viruses in the mixed series were always substantially lower than those recorded when the strains were used individually as seed in the same concentrations as were employed in the mixed series. Assay of the infectivity titers of the individual strains in the presence of appropriate immune sera led to the demonstration that the time required for the growth cycle of influenza B virus varied with the dose of seed virus. With undiluted infected allantoic fluid as seed only 4 to 5 hours elapsed before new generations of virus were liberated. With increasing 10-fold dilution of the seed the constant period became increasingly longer until it stabilized at 8 to 10 hours. This finding offers an explanation for the seeming discrepancy between the observations on interference between the 2 viruses and the difference reported previously in the extent of their growth periods, on the one hand, and the fact that the 2 agents could be carried simultaneously in series through numerous passages in the chick embryo.

Humans↗