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 balance (8.6), produced a significant protective effect when injected in a dose of 2000 microg/mouse 2 days before
aerosol infection of mice with influenza virus. A moderate protective effect was also observed using a second preparation, designated N2. One day after
aerosol infection, animals pre-treated with 2000 microg 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 spleen and thymus weights was, observed in the mice. One day after injection of these preparations, the number of lymphocytes in the bronchoalveolar tract of the mice exceeded almost twice that seen in mice treated with placebo. After 3 days, relative and absolute numbers of macrophages decreased, whereas those of lymphocytes increased significantly. Three days after the administration of preparations N1 and N2, macrophages became approximately twice as active in absorbing zymozan granules. Preparation N1 affected the system of
superoxide radical anion production to a greater extent than preparation N2. The production of radical
anions by the macrophages of the bronchoalveolar tract in the mice, 1 day after
intramuscular injection of preparation 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
emulsions of
polyprenols that have relatively low hydrophilic-lipophilic balance, inhibit influenza virus
infection in mice through a modulation of the host immune response.