Myeloid peritoneal cells in MOSEC-bearing mice suppress T cell proliferation independently of NADPH oxidase.

<p>Purified myeloid (CD11b⁺) PECs from MOSEC-bearing WT and p47<i>^phox−/−</i> mice were co-cultured with CFSE-labeled splenocytes from naïve mice (E∶T ratio: 1∶1) in anti-CD3/B7.1-coated plates. After 72 h of culture, CD4⁺ and CD8⁺ T cell proliferation was assessed based on CFSE dilution as described in methods. A) Representation histograms showing that CD11b⁺, but not CD11b⁻, PECs from MOSEC-bearing WT and p47<i>^phox−/−</i> mice (day 90) completely suppress anti-CD3/B7.1-stimulated CD4⁺ T cells proliferation. Anti-CD3/B7.1 stimulated and unstimulated CD4⁺ T cells are used as positive and negative controls, respectively. B) CD11b-enriched PECs from MOSEC-bearing WT and p47<i>^phox−/−</i> mice at day 42 equally suppress both CD4⁺ and CD8⁺ T cell proliferation. In contrast, CD11b⁻ PECs from the same mice incompletely suppressed anti-CD3/B7.1-stimulated T cell proliferation. C) CD11b-enriched PECs from MOSEC-bearing WT and p47<i>^phox−/−</i> mice at day 90 completely suppressed T cell proliferation while the CD11b-negative fraction had no significant effect on T cell proliferation. Myeloid PECs collected on day 42 were pooled because of limited cell number, while non-pooled PECs from individual mice were analyzed from day 90 harvests. Individual experiments were performed using PECs from 3 mice per genotype per time point, and each experiment was repeated at least once using PECs from different mice, with similar results. Comparison between genotypes: p = NS.