2D and E). Upon further analysis of pro-inflammatory cytokine production, we found that CD3+CD4− γδ TCR+ cells accounted for approximately 50%
of total IFN-γ-producing cells (Fig. 3A). The kinetic analysis of cytokine production revealed that resident γδ T cells were the predominant cytokine-producers in the mesLN and LP of TCR-β−/− recipient mice during the early phase of intestinal inflammation (Fig. 3B and C). We observed that γδ T cells from TCR-β−/− recipient mice reconstituted with CD4+CD25− TEFF cells alone produced either IFN-γ or IL-17 (15 and 5% respectively) (Fig. 3D and E) throughout colitis development, and this represented over 80% of total IFN-γ- and IL-17-producing cells 4 days post CD4+ T-cell transfer (Fig. 3B and C). At a later stage of intestinal inflammation, the balance of cytokine high throughput screening compounds R428 supplier expression between γδ and αβ T cells tipped in favor of αβ T cells, as 70–80% of IFN-γ-/IL-17-secreting cells in the LP originated from donor CD4+ TEFF pool (Fig. 3B and C). In all instances, co-transfer of CD4+CD25+ TREG cells potently inhibited the priming, differentiation and accumulation of IFN-γ-/IL-17-producing CD4+ and γδ T cells in mesLN and LP (Fig. 3D and E). It is noteworthy
to mention that, although some recent studies suggest functional differences in peripheral (non-mesenteric) γδ T cells between WT and TCR-β−/− mice 48, the cytokine profile of mesenteric γδ T cells isolated from TCR-β−/− mice was similar to the cytokine profile of WT mesenteric γδT cells in our experiments (data not shown). While CD4+ T cells are the primary mediators of disease in our model, it has been suggested that B cells largely play an important regulatory role as the onset of colitis is delayed in immunodeficient recipients 19, 49–51. As the role of γδ T cells in colitis development is unknown in our system, we compared the onset and severity
of T-cell-induced intestinal inflammation between TCR-β−/− (lacking only αβT cells) and RAG2−/− (lacking all lymphocyte lineages) mice. To this end, both host strains were reconstituted with WT CD4+CD25− TEFF cells, and the onset of colitis Hydroxychloroquine mw as well as cytokine profile was compared. By 10 days post TEFF cells transfer, TCR-β−/− recipient mice rapidly began to show clinical signs of colitis development and lost 30% of their initial body weight within 3 wk (Fig. 4A). In contrast, RAG2−/− recipient mice showed a delayed onset of colitis and less severe body weight loss (>20%) by 3–5 wk post T-cell transfer (Fig. 4A). Histological analysis of colonic tissues of TCR-β−/− and RAG2−/− recipient mice 30 days post TEFF cell transfer revealed similar levels of global, intestinal inflammation. However, we observed some differences in the cellular architecture of the inflamed, colonic tissues of TCR-β−/− and RAG2−/− mice.