[Mechanism of the negative action of a bacterial lipopolysaccharide (pyrogenal) on the course of experimental ornithosis infection].

The intravenous injection of pyrogenal into mice following their intravenous infection aggravates the course of ornithosis infection and leads to more intensive multiplication of the infective agent. After the injection of pyrogenal is discontinued a change in the course of the infectious process occurs and the infective agent is quickly eliminated from the body. This is accompanied by increased formation of specific antibodies. The negative effect of pyrogenal is due to its high toxicity for macrophages containing the colonies of the infective agent, the suppression of the reaction of neutrophil leukocytes at the sites of the destruction of infected cells and the suppression of the general reaction of the mononuclear phagocytic system. Pyrogenal does not damage lymphoid tissue and even produces an immunostimulant effect on it, but the increased immune response can be completely realized only after pyrogenal injections are stopped and the reaction of mononuclear phagocytes is restored.