NITRIC-OXIDE INHIBITS PROLIFERATION BUT INCREASES LIFE-SPAN OF T-LYMPHOCYTES IN TUMOR-BEARING RATS

Nitric oxide (NO) has been shown to inhibit the proliferation of lymph ocytes. However, in tumour-bearing rats treated with the immunomodulat or OM 163, the regressing nodules were heavily infiltrated by T lympho cytes, although they contained high levels of NO. We show here that NO , while inhibiting the proliferation of lymphocytes, increased their l ife-span, pointing to the ambivalence of this molecule in the course o f tumour growth and regression.