[Action of plant extracts on the natural immunity indices of animals].
The influence of extracts from oak bark, St. John's-wort leaves and pine buds on natural immunity characteristics of mice has been studied. The injection of these extracts into mice has been found to enhance their resistance to infection with Staphylococcus aureus and Bordetella pertussis virulent cultures, to decrease the enzymatic activity of 5'-nucleotidase in the peritoneal exudate macrophages of mice and to increase the level of lysozyme in their blood. The action of these extracts has proved to depend on their dosage and the time of observation.