Mechanism of interferon action. Activation of macrophages and antagonism to alpha-feto-protein by pppA2'p5'A2'p5'A.

pppA2'p5'A2'p5'A(2'-5'P3A3) activates macrophages and increases the phagocytosis of macrophages from different species including human beings. This indicates that the activation of macrophages may be a general action of 2'-5'P3A3. This discovery broadens the effect of 2'-5'P3A3 beyond the antiviral field. alpha-Feto-protein (AFP) inhibits the phagocytosis of macrophages and may be involved in the development of hepatoma. Data presented here show that 2'-5'P3A3 can antagonize this suppressive effect of AFP. Methods used so far for introducing 2'-5'P3A3 into the cells were made with the aid of CaCl2, etc. under conditions which may not be the same as those used clinically. It was found that 2'-5'P3A3 can develop its biological effect without the aid of CaCl2, etc.