Hematopoietic Cancer Cell Lines Can Support Replication of Sabin Poliovirus Type 1

Figure 1

Viral titer in CCID50 value (a) or D-antigen level (c) of Sabin poliovirus type 1 per mL during serial passaging of Sabin poliovirus type 1 in hematopoietic tumor cell lines. Vero cells were used as a positive control cell line, whereas CHO cells served as a negative control. For the first infection, cells were infected with an MOI of 1, and cells together with supernatant were harvested after 3–6 days. After freeze-thawing of the material, half of it was used to reinfect fresh cells. This was repeated for 4 times. The virus titer in the 5 viral passages was determined by titration assay and the results are shown in (a). In (b) light microscopic images of uninfected or cells infected with Sabin poliovirus type 1 from passage 4 at day 6 (KG1 and K562) or day 3 (U937) are shown, whereas in (c) the D-antigen levels/10⁷ CCID50 for the fifth viral passage is shown.

(a)

(b)

(c)