Effect of 2′5′-oligoadenylic acid on a mouse cell line partially resistant to interferon

We have investigated the sensitivity of a mouse cell line, NIH 3T3 (clone 1), that was found to be resistant to the anticellular and certain antiviral activities of interferon, to 2′,5′-oligoadenylate (2′5′A). The 2′5′A was introduced into the cells by coprecipitation with calcium phosphate and by increasing cell permeability with lysolecithin. In both cases neither cellular protein nor DNA synthesis was inhibited by 2′5′A in the NIH 3T3 cells. In contrast, the synthesis of proteins and DNA in L cells, an IFN sensitive line, was inhibited by low concentrations of 2′5′A. Furthermore, treatment of the infected cell cultures with 2′5′A resulted in the inhibition of vesicular stomatitis virus (VSV) replication in L cells but not in NIH 3T3 cells. The production of MuLV in NIH 3T3 cells was also not affected by 2′5′A. These observations, together with our previous finding that NIH 3T3 (clone 1) cells are deficient in RNase F activity suggest that activation of the RNase F by 2′5′A is responsible for the inhibition of both protein and DNA synthesis in sensitive cells.