In vivo toxicity to lymphoid tissue by 2'-deoxycoformycin.

The enzyme adenosine deaminase has an essential role in lymphocyte metabolism. To examine the in vivo effects of inhibition of this enzyme healthy BDF1 mice were injected intraperitoneally with 2'-deoxycoformycin, a stoichiometric tight-binding inhibitor of adenosine deaminase. Of the treated animals, 20% died of overwhelming infection, and histopathological examination of these, and surviving animals sacrificed 10 days following treatment indicated a selective toxicity to lymphoid cells. No toxicity to tissues other than the lymphoid system was observed, which is consistent with the hypothesis that 2'-deoxycoformycin offers a new and selective approach to the treatment of lymphoid malignancies.