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Feline fibrosarcoma virus: Quantitative focus assay, focus morphology and evidence for a “helper virus”
Author(s) -
McDonald Ruth,
Wolfe Lauren G.,
Deinhardt Friedrich
Publication year - 1972
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/ijc.2910090108
Subject(s) - biology , marmoset , virus , fibrosarcoma , fibroblast , virology , callithrix , cell culture , microbiology and biotechnology , paleontology , genetics
Feline fibrosarcoma virus (FeSV) was assayed by focus formation in feline and marmoset fibroblast cultures overlaid with agar and re‐fed with fluid media. The FeSV titers were consistent from experiment to experiment and were about four times higher in feline fibroblasts than in marmoset fibroblasts in parallel assays. Clones of FeSV‐infected cells grown in soft agar, and foci of transformed cells produced by FeSV in monolayer cell cultures were both of two morphological types: round cells (r) and a loose meshwork of fusiform and round cells (fr). Thermal stability experiments indicated that the morphological differences of the foci were virus‐dependent. The titration pattern of FeSV grown in marmoset or feline cells indicated that these preparations were either competent or contained an excess of helper virus. Preliminary challenge experiments with Snyder‐Theilen FeSV grown in marmoset cells indicated that a 10‐ to 100‐fold excess of non‐transforming, interfering virus (helper virus) was present in this FeSV preparation.