Abstract
A survey was made of mycoplasma contamination in cell lines and transplantable tumor lines maintained in laboratories in Japan. A total of 60 cell lines were tested and 52 (86.7%) of which were contaminated by mycoplasmas. These mycoplasmas were isolated from the cell lines of human origin 10/13 (77%), from monkeys 3/3 (100%), from rats 14/19 (74%) and from mice 25/25 (100%). Mycoplasmas were not found in any of the 99 samples of tumor materials, Mycoplasma colonies, upon primary isolation from cell lines, could be differentiated into three morphological types. However, all colonial types showed similar biological properties. All but one of the isolated mycoplasmas could be identified as Mycoplasma hominis type 1 by both growth inhibition tests and by fluorescent antibody technique.
