Augmentation of natural killer activity by pyran copolymer in mice.

Treatment of older mice with pyran copolymer, a known interferon-inducer, was found to result in a rapid boosting of cell-mediated cytolytic activity against YAC-1 tumor target cells. The effector cells were characterized as being non-adherent and were presumed to be natural killer (NK) cells. Augmentation occurred in various lymphoid organs and was detectable 2-3 days after drug treatment. Differences in the levels of boosted activity among the lymphoid organs resulted when the route of administration was varied. The degree of augmentation was largely independent of the dose of pyran, but did vary among different strains of mice. Augmentation, moreover, was followed by a rapid decline by 5-7 days.