Lack of correlation between thymidine kinase activity and the antiviral or antiproliferative response to interferon.

Murine L cells lacking thymidine kinase activity (Ltk-) do not respond to the antiviral or antiproliferative activity of interferon, whereas human tk- cells show a normal response. Furthermore, a clone of tk+ cells derived from Ltk- cells by DNA-mediated transfer of the tk herpes gene does not respond to interferon. Cells of this clone and Ltk- cells do not produce interferon when infected with Newcastle disease virus or treated with poly(I) X poly(C) and DEAE-dextran. Possible reasons for this inability to produce interferon and the lack of response to interferon are discussed.