Polyadenylic-polyuridylic acid: biological response-modifying activities in mice. In vivo organ distribution and pharmacokinetics in rabbits.

Lack of toxicity of polyadenylic-polyuridylic acid [poly(A).poly(U)] in rodents is demonstrated. This immunomodulator has antitumor activity when used as an adjuvant to surgery or to chemotherapy. Biological mediator properties that shed some light on the mechanism of tumor inhibition are the potentiating effects of poly(A).poly(U) on T cells, natural killer cells, and interferon activity as indicated by the level of the enzyme 2-5 A synthetase. In vivo organ distribution and pharmacokinetic studies in rabbits by a scintigraphic technique, subcellular fractionation, and sucrose sedimentation profiles indicate a surprising metabolic stability (measured in days).