Fig 2: Differences between contact and prostaglandin blocked co‐incubations of activated CD4+ T‐cells with MSCs. A, With contact, co‐incubations with MSCs reduced CD4+ T‐cell expression of IFNγ. However, without prostaglandin signaling, IFNγ expression was not reduced. B, Expression of intracellular FoxP3 was reduced in the presence of MSCs both with and without prostaglandin signaling. C, While co‐incubations with MSCs reduced CD25 expression in contact co‐incubations, without prostaglandin signaling, no reduction of CD25 was seen. D, CD62L expression by activated CD4+ T‐cells was reduced in co‐incubations both with and without prostaglandin signaling. *P < .05; PGE, prostaglandin

Fig 3: Differences between contact and no contact co-incubations of activated CD4+ T-cells with MSCs. Co-incubation with MSCs induced a reduction in expression of intracellular IFN? (A) and FoxP3 (B) both with contact and without contact. (C) While co-incubation with MSCs reduced activated CD4 + T-cells expression of CD25 with contact, without contact, no reduction of CD25 was seen. (D) Co-incubations with MSCs without contact did not reduce CD4+ T-cell expression of CD62L. *P < .05

Fig 4: CD4+ T-cells have a lowered activation phenotype after four day co-incubation with MSCs. (A) CD4+ T-cells had lowered expression of CD25 when co-incubated with MSCs, both with and without activation by PHA. (B) Intracellular IL-10 showed no change based on co-incubated with MSCs. Intracellular FoxP3 (C), intracellular IFN? (D), and surface CD62L (E) expression was lowered in activated CD4+ T-cells that were co-incubated with MSCs. Data are presented as mean ± standard error of the mean. *P < .05; CD4, CD4+ T-cells; MSC, mesenchymal stem cells; PHA, phytohemagglutinin

Fig 5: CD4+ T-cells show increased levels of IFN? expressing CD4+ T-cells. (A-C) ERU horses and control horses express similar levels of CD25+, IL10+ and FoxP3+ CD4+ T-cells. (D-E) ERU have significantly higher levels of IFN?+ CD4+ T-cells and CD62L+ CD4+ T-cells. Data are shown as box and whisker plots with a mean value shown as the middle bar and the range being from minimum to maximum value. Open dots represent outliers. *P < .05