Nucleases and adenosine 3',5'-cyclic monophosphate phosphodiesterase activities in murine sarcoma virus (Moloney)-infected mice.

To provide information on the role of nucleases in oncogenic virus infection, the activities of 3'-nucleotide phosphodiesterase (3'-NPDase), 5'-nucleotide phosphodiesterase (5'-NPDase), acid deoxyribonuclease (DNase II), and 3',5'-cyclic AMP phosphodiesterase (cAMPDase) in spleen extracts of murine sarcoma virus-infected C57BL/6 inbred mice were studied. At the peak of tumor growth and of the cell-mediated cytotoxic response (CMC) against tumor-associated antigens, 3'-NPDase, 5'-NPDase, and DNase II all showed depressed activities in the spleen, whereas the activity of cAMPDase in the spleen increased at the peak of CMC and remained elevated thereafter. Serum enzyme activities of the infected mice were also determined, and only 3'-NPD-ase in serum correlated well with CMC. Inasmuch as the correlation of the tumor growth with CMC was established in this system, further study on tumors with variance between CMC and growth is necessary to determine if serum 3'-NPDase is a useful biochemical marker for CMC in vivo.