Gram-positive and gram-negative bacteria induce different patterns of cytokine production in human mononuclear cells irrespective of taxonomic relatedness.
Upon bacterial stimulation, tissue macrophages produce a variety of cytokines that orchestrate the immune response that clears the infection. We have shown that Gram-positives induce higher levels of interleukin-12 (IL-12), interferon-gamma (IFN-gamma), and tumor necrosis factor (TNF) from human peripheral blood mononuclear cells (PBMCs) than do Gram-negatives, which instead induce more of IL-6, IL-8, and IL-10. Here, we study whether these patterns follows or crosses taxonomic borders. PBMCs from blood donors were incubated with UV-inactivated bacteria representing 37 species from five phyla. IL-12, TNF, IL-1beta, IL-6, IL-8, and IL-10 were measured in the supernatants after 24 h and IFN-gamma after 5 days. Irrespective of phylogenetic position, Gram-positive bacteria induced much more IL-12 (nine times more on average) and IFN-gamma (seven times), more TNF (three times), and slightly more IL-1beta (1.5 times) than did Gram-negatives, which instead induced more IL-6 (1.5 times), IL-8 (1.9 times), and IL-10 (3.3 times) than did Gram-positives. A notable exception was the Gram-positive Listeria monocytogenes, which induced very little IL-12, IFN-gamma, and TNF. The results confirm the fundamental difference in innate immune responses to Gram-positive and Gram-negative bacteria, which crosses taxonomic borders and probably reflects differences in cell wall structure.
Skovbjerg
Susann
S
Department of Infectious Medicine/Clinical Bacteriology, Institute of Biomedicine, University of Gothenburg, Göteborg, Sweden. susann.skovbjerg@vgregion.se
Martner
Anna
A
Hynsjö
Lars
L
Hessle
Christina
C
Olsen
Ingar
I
Dewhirst
Floyd E
FE
Tham
Wilhelm
W
Wold
Agnes E
AE
D000942:Antigens, Bacterial / Q000276:immunology; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D006090:Gram-Negative Bacteria / Q000276:immunology*; D006094:Gram-Positive Bacteria / Q000276:immunology*; D006801:Humans; D007113:Immunity, Innate; D018836:Inflammation Mediators / Q000378:metabolism*; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism* / Q000382:microbiology* / Q000473:pathology; D008213:Lymphocyte Activation; D010587:Phagocytosis / Q000276:immunology; D013045:Species Specificity; D014466:Ultraviolet Rays
D000942:Antigens, Bacterial; D016207:Cytokines; D018836:Inflammation Mediators