Interferon Preparations as Modifiers of Immune Responses

Within certain dose ranges, preparations of mouse serum interferon or tissue-culture interferon show a modest capacity to increase the number of antibody-forming spleen cells in mice as measured by the Jerne plaque technique. When low levels of polyadenylic polyuridylic acid (= poly A:U), i.e., an amount that causes only modest stimulation, were used together with amounts of the interferon preparations that also by themselves are ineffective, a good stimulation of early appearance of antibody-forming cells was produced. High concentrations of IF preparations reduced antibody formation, and the potent immunoenhancing effects of chlorite-oxidized amylose (COAM) were almost completely abolished in the presence of low concentrations of interferon preparations. These findings suggest certain similarities between the effects of interferon preparations and those of agents known to modify the cyclic AMP system. Such suspected relationships are supported by preliminary data demonstrating a capacity of IF preparations to elevate adenyl cyclase activity and cAMP levels in mouse spleen cells.