[Spontaneous contamination of primary green monkey kidney cell cultures by foamy virus].

Examinations of 1653 batches of green monkey kidney cell cultures revealed contamination with foamy virus (FV) in 243 (16%) batches. From some of these cultures 65 strains of virus belonging to two serotypes were isolated. Tests on sera from 1122 monkeys revealed antibody to FV in 985 (87.8%) animals. No correlation between the presence of antibody in the serum and virus recovery from monkey kidney cell cultures was observed, however. This might be due either to the lack of the virus in the kidneys or to the failure in its isolation from primary cultures. Passages of cell cultures were shown to facilitate additional recovery of FV. These experimental results may be used for screening and selection of FV-free cultures and for control purposes in the course of vaccine manufacture.