[Inflammation and antibacterial resistance. III. Influence of an inflammatory reaction induced by the injection of polyacrylamide gels on the resistance of mice to Listeria monocytogenes infection].

Inflammation was induced in the dorsal area of pathogen-free mice following subcutaneous injection of polyacrylamide microbeads (Biogel) of varying particle size (200-400 mesh) and pore size (exclusion limit ranging from a molecular weight of 2,000 to 300,000). Six days after injection of the microbeads, mice were infected with 10(5) Listeria monocytogenes. Only animals injected with "Biogel P2, P4, P6" (exclusion limit 2,000, 4,000 and 6,000 respectively) survived this lethal inoculum of Listeria. A study of the kinetics of this increased resistance revealed that homogenates of granulomas, induced eight days before injection into mice, significantly decreased the number of listeria in the spleen of treated mice. Such increased resistance was not found in cell homogenates, but only in the exudate of 8-day old granulomas. Fractionation studies of the inflammatory exudates with ammonium sulfate showed that immunostimulating substance were present in the supernatant following precipitation with 80% saturated (NH4)2SO4.