Mycoplasma Isolates from Primary Cell Cultures and Human Diploid Cell Strains.

Mycoplasmas were isolated from “uninoculated” cultures of human diploid cell strain (HDCS) WI-26, and primary cultures of African green monkey kidney and chick embryo. These 3 Wistar mycoplasma strains were characterized by their ability to produce CPE in cultures of HEK, GMK, CE, and HDCS; ferment sugars; and cause beta hemolysis of guinea pig erythrocytes. HDCS cultures subcultured routinely after infection with these strains could not be propagated for their usual finite life span and “early senescence” occurred 10 to 20 passages before that in uninoculated control cultures. Complement fixation and growth inhibition studies revealed that these mycoplasma strains were serologically similar to each other, if not identical, and were related to the unclassified GDL strain of Butler and Leach (14). However, the Wistar strains were not related to the known human prototypes of mycoplasmas nor to 16 animal serotypes for which standard typing reagents were available.