Effect of intramuscularly injected polyprenols on influenza virus infection in mice

This study demonstrates the possibility of achieving a prophylactic effect by intramuscular injection of Abies sibirica polyprenols for the control of influenza virus infection in mice. One of the five polyprenol preparations tested, preparation N1. which had the lowest hydrophilic-lipophilic balanc e (8.6), produced a significant protective effect when injected in a dose o f 2000 mu g/mouse 2 days before aerosol infection of mice with influenza vi rus. A moderate protective effect was also observed using a second preparat ion, designated N2. One day after aerosol infection, animals pre-treated wi th 2000 mu g doses of the polyprenol preparations or Hanks' solution showed no difference in the level of interferon accumulation in the lungs. Three days after injection of preparation N2 and N1, a significant decrease in sp leen and thymus weights was observed in the mice. One day after injection o f these preparations, the number of lymphocytes in the bronchoalveolar trac t of the mice exceeded almost twice that seen in mice treated with placebo. After 3 days, relative and absolute numbers of macrophages decreased, wher eas those of lymphocytes increased significantly. Three days after the admi nistration of preparations N1 and N2, macrophages became approximately twic e as active in absorbing zymozan granules. Preparation N1 affected the syst em of superoxide radical anion production to a greater extent than preparat ion N2. The production of radical anions by the macrophages of the bronchoa lveolar tract in the mice, 1 day after intramuscular injection of preparati on N1, was significantly higher than that seen on day 3 and that induced by preparation N2 1 and 3 days after injection. These data indicate that emul sions of polyprenols that have relatively low hydrophilic-lipophilic balanc e, inhibit influenza virus infection in mice through a modulation of the ho st immune response.