[Some parameters of the production of a type D retrovirus (PMFV) in human cells (author's transl)]

The production of a type D retrovirus (PMFV) was analysed using different conditions of cultivation. Both in cell culture flasks and in roller culture bottles with discontinuous change of medium an increase of virus amount was determined within 12 h after seeding of virus-infected cells. Then the virus production considerably fluctuated around an apparent mean value until the end of the experiment at 56 h. In case of a continuous change of cell culture medium in roller bottles a maximum of virus production was measured at a retention time of 24 h of cell culture medium. The production of PMFV could be essentially increased when virus-producing cells were co-cultivated with non-infected cells of the same type.