Figure 1
Neisseria gonorrhoeae (Ngo) induces abundant production of interleukin (IL)-10 and type 1 regulatory T (Tr1) cells in BALB/c mouse iliac lymph node (ILN) cells, CD4+ T cells, and genital tract explants. (a) Cytokine secretion by ILN cells stimulated with N. gonorrhoeae or with Escherichia coli (multiplicity of infection (MOI) 10:1 or 50:1). After 4 days of culture, supernatants were collected and the cytokine levels were measured by enzyme-linked immunosorbent assay. (b) Intracellular staining for IL-10 in different immune cell types in ILN cell cultures after stimulation with N. gonorrhoeae (MOI 10:1) for 4 days. Cells were recovered, stained for surface markers and intracellular IL-10, and analyzed by flow cytometry. (c) Time course of cytokine production by ILN cells stimulated with N. gonorrhoeae (MOI 10:1). (d) Intracellular staining for IL-10, IL-4, and forkhead box p3 (Foxp3) in CD4+ T cells after stimulation with N. gonorrhoeae (MOI 10:1) for 4 days. The expression levels of cytokines and Foxp3 were analyzed by flow cytometry with gating on live CD4+ T cells. (e) Intracellular staining for transforming growth factor-β (TGF-β) in gated CD4+/IL-10+/IL-4–/Foxp3– Tr1 cells after stimulation with N. gonorrhoeae (MOI 10:1) for 4 days. (f) Cytokine secretion by purified CD4+ T cells stimulated with N. gonorrhoeae (MOI 10:1 or 50:1) in the presence of mitomycin C-inactivated antigen-presenting cells (APC) for 4 days. (g) Comparison of the percentages of induced Tr1 cells in CD4+ T cells between ILN cell cultures and purified CD4+ T-cell cultures stimulated with N. gonorrhoeae (MOI 10:1 or 50:1) for 4 days. (h) Cytokine secretion by genital tract explants stimulated in vitro with N. gonorrhoeae (1 × 107 or 5 × 107 colony-forming units (CFUs) ml−1) for 4 days. All data shown are representative of four independent experiments. *P<0.01 N. gonorrhoeae- vs. E coli-stimulated (a) or purified CD4 T cells vs. lymphocyte culture (g). IFN, interferon.
