Rabbits exposed repeatedly to aerosols of endotoxin-containing microvesicles (ECMV) of the outer membrane of the Pantoea agglomerans strain isolated from airborne grain dust showed a large increase in the concentration of circulating cytokines: total interferon (IFN), interleukin-1 alpha (IL-1 alpha), and tumor necrosis factor alpha (TNF alpha). The increase was significantly higher compared to animals exposed to control saline (p<0.001). Aerosol exposure to ECMV also induced the formation of specific precipitin antibodies and lymphocyte activation. The results indicate strong immunomodulative properties of ECMVs produced in nature by Pantoea agglomerans bacteria, and heavily contaminating organic dusts.
Three different strains of NDV and antiviral veterinary vaccines, i.e. Poxvac I, Poxvac K, Canivac F, Lapest and Suivac A, were used as inducers of interferon production. The following cells were used: bovine embryo cells (tracheal and nosopharyngeal epithelium), skin and kidney fibroblasts, MÍDBK cell line and cultures of blood and spleen leukocytes. Of the viruses used, only three strains of NDV, Suivac A and Bayferon were active in the induction of bovine IFN. Synthetic RNA poly: poly C also elicited IFN production in the bovine skin fibroblasts and in blood leukocytes, especially when the cells were treated before induction with low concentrations of interferon („priming”), or when inhibitors of transcription and translation were used for the inhibition of IFN genes repressors synthesis („superinduction”). Superinduction caused a high increase in the final IFN yield, i.e. 5-fold from Bf and 16-fold from bovine leukocytes.