Abstract: | Three hybridoma cell lines producing monoclonal antibodies to lambda phage were cultured for 9 months in Dulbecco's modified Eagl's medium supplemented with 10% fetal calf serum or with 5% swine serum. Under these conditions all the clones had the same proliferation rates and maximum population densities. The cultuvation in the medium with swine serum enhanced the stability of hybridomas: all clones retained the ability to produce antibodies throughout the experiment; one of the clones examined enhanced the activity by 10(3)-10(4) times. When the same three clones were cultured in the medium with the fetal calf serum, two of them lost their ability to produce antibodies 3-15 weeks after the beginning of the experiment. |