Retrovirus-Like Particles Released by Human Prostatic Cells

A cell strain has been obtained from an explant culture of a human prostatic tissue. The tissue was diagnosed as benign prostatic hyperplasia. Cultured cells displayed human male karyotype and chromosome modal number of 43–46. Cultures of these cells appear to release retrovirus-like entities. The extracellular particulate material obtained from the culture medium showed the following characteristics: (1) it banded at a density of 1.12–1.18 g/ml in a sucrose density gradient; (2) it contained particles with a sedimentation rate approximating that of the known retroviruses; (3) these particles contained RNA and RNA-directed DNA polymerase; (4) the RNA-directed DNA polymerase utilized poly (Cm) as a template, and (5) the particles synthesized DNA in an endogenous DNA polymerase reaction. The DNA thus synthesized was associated with RNA, some of it with high molecular weight RNA. These observations can be interpreted to suggest that human prostatic cells produce retrovirus(es). However, we were not able to detect a 60–70S RNA species in the labeled RNA of the released particles. The isolated RNA, however, displayed a 30–35S component.