MICROFLORA-ASSOCIATED DEFENSE STIMULATING FACTORS

Mucosal surfaces are habitats for the physiological microflora and are closely related to the mucosal immune compartment (mucosa-associated lymphoid tissue, MALT). Recently, considerable evidence has accumulate d showing that various members of the physiological microflora liberat e low molecular weight substances which, apparently, are essential for the adequate immune response of the host. Antibiotic decontamination (e.g. of the BALB/c mouse gastrointestinal tract) results in a lack of generation of immunopriming microbial substances leading to immunosup pression. Biochemical analysis of the microbial substances revealed re producible chromatographic fractions which selectively influence matur ation, proliferation and activation of mononuclear immune cells.