[Effect of the size of the continuous poly(G) site in poly (G, A).poly (C) complexes on their interferon-inducing activity and their capacity to stimulate the development of immunity].

It was established that the level of interferon-inducing activity of poly(G90A1).poly(C) complex in cell cultures and in mice was comparable to that of poly(G).poly(C). As the size of the continuous sites of poly(G) in the purine strand in poly(G, A).poly(C) complexes decreased to 60 and 28 nucleotides, the interferon-inducing activity decreased progressively, was still marked, or approached the zero at G:A ratios equal to 17:1 or 10:1, respectively. All this indicates that the cell receptors responsible for switching on of the induction mechanisms for interferon synthesis still recognize the stimulus 17 and possibly less so stimulus 10 of successively located guanosine nucleotides complementary to poly(C) and provide for the highest interferon production level when their number is equal to or exceeds 90-100. With the exception of poly(G10A1).poly(C) in which the interferon-inducing activity did not exceed its detection threshold, all complexes enhanced noticeably or markedly specific immune response in mice to tick-borne encephalitis after immunization with inactivated unadsorbed tissue culture vaccine against this infection. The level of this immunostimulating activity correlated irregularly with the intensity of their interferon-inducing activity.