Lymphocytes of small mammals: spontaneous transformation in culture to blastoids.

Small lynmphocytes froni rabbit and guinea pig, grown in tissue culture in the absence of phytohemagglutinin, can transform spontaneously into cytologically immature cells that are indistinguishable morphologically from blast cells. The transformation occurs in 38 to 75 percent of peripheral lymphocytes and 55 to 75 percent of splenic lymphocytes on the 5th day of culture. The altered cells can synthesize RNA and DNA and show mitotic division; synthesis of DNA occurs after the 5th day of culture, whereas RNA is synthesized throughout the duration of culture.