Mycoplasma Contamination Revisited: Mesenchymal Stromal Cells Harboring Mycoplasma hyorhinis Potently Inhibit Lymphocyte Proliferation In Vitro
Figure 5
Mycoplasma-infected MSC inhibit T lymphocyte proliferation in vitro as measured by CFSE dilution.
Previously uninfected (light gray histograms) and intentionally infected PVG.7B MSC (dark gray; cf. Figure 4B) were added to CFSE-labeled, Con A-stimulated PVG.7B LNC (values to the left denote the log of MSC:LNC ratios). LNC alone were cultured either with (black histogram) or without (white) Con A as positive and negative controls, respectively. CFSE dilution indicating cell divisions was measured by flow cytometry after 3 d of incubation. Histogram plots (percent of maximum count) are representative of triplicates and show the fluorescence intensity of lymphocyte populations gated on CD3+CD4+CD8− (CD4 T cells) and CD3+CD4−CD8+ (CD8 T cells). The potent inhibition of lymphocyte proliferation by infected MSC measured by CFSE dilution cannot be explained by degradation of [3H]TTP. For the highest dilution (−6) of mycoplasma-infected MSC, individual cultures displayed either full inhibition or full proliferation (cf. Figure 3); one replicate in which full lymphocyte proliferation was detected is shown. Data are representative of three independent experiments.