Figure 1.
The CD81 genotype of Balb/c macrophage cells in continuous tissue culture was assessed over time. Upper Panel) Balb/c cells were assessed after 13, 20, 35, 42, and 50 in vitro passages for the presence of CD81 DNA by PCR using primers and conditions described in the Materials and Methods. The passage number (P) is presented below the Figure and the amplicon is identified on the left side of the Figure. Lower Panel) Ratio of CD81/14S ribosomal protein DNA over time. Ratio was determined semi-quantitatively by densitometry. The points indicated are from the data in the upper panel.