Background: Bioaerosol-related airborne dermatitis was reported on e.g. in farmers and sewage workers. Bioaerosols consist of Gram-negative bacteria and so-called microvesicles (MV) emerging as a result of disruption of the bacteria. The present study was aimed at assessing the proinflammatory properties of microvesicles in vitro.
Methods: MV were produced through disruption of the bacterial wall of the Gram-negative bacterium Pantoea agglomerans (Erwinia herbicola). Peripheral blood mononuclear cells (PBMC) of five healthy volunteers were cultured for 6 h, 24 h, 3 days, and 5 days with dilution series of MV ranging from 0.48 - 1500 µg/ml. The following variables were observed: secretion of IFN-γ and TNF-α (ELISA and ELISPOT assays), intensity of cell proliferation (LPT), expression of surface markers CD8, CD14, CD16, CD25, CD69, CD80, CD83, HLA-DR, the apoptosis marker Annexin V, and PI permeability (flow cytometry).
Results: After 24 hours, a clear dose-dependent response to MV was seen for IFN-γ production starting already with the lowest MV concentration of 0.48 µg/ml (p=0.042). As for TNF-α, a significant (p=0.05) increase in the production of this cytokine was seen after 3 days at MV concentrations of 300 µg/ml or higher. On the LPT, there was a clear and significant dose-response to MV after 5 days (p=0.001). Regarding expression of cell surface markers, the only phenomenon seen in all donors was the decrease in the number of CD14(+)CD83(+) cells with increasing MV concentration (probably due to increased MoDC maturation).
Conclusion: We have shown that microvesicles are biologically active in PBMC cultures in a dose-dependent manner. IFN-γ production was increased already at lowest MV doses tested. These results explain clinical observations on the proinflammatory effect of bioaerosols on the skin.
Sensimun (formerly Celimun) biomedical research outsourcing in allergy and immunology
ELISpot - training and implementation
ELISpot - scanning and analysis of ELISpot plates
Sensimun (dawniej Celimun)- badania biomedyczne na zlecenie
Institute of Dermatology, Krakow, Poland
Instytut Dermatologii w Krakowie
© Radoslaw Spiewak. (contact).
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Document created: 29 August 2006, last updated: 25 November 2021.