[The inhibition of the cellular immune response by Pseudomonas aeruginosa extracts]

Aquatic-phenol trichloroacetic and salt extracts of Pseudomonas aeruginosa have been studied for their effect on hypersensitivity of the delayed type to guinea pig antigen in mice. It is found that salt extracts of wild strains contain thermostable immunosuppressive factors which are of the lipid nature, have high molecular weight and can be inactivated by trichloroacetic acid and phenol. The salt extracts of museum strains as well as aquatic-phenol and trichloroacetic extracts obtained from wild and museum strains had no immunosuppressive activity.