The effects of CD200R and CD200 mAb on T cell activation.

<p>(A) Schematic representation of the assay showing engagement of Moth Cytochrome C peptide (MCC), MHC-TCR and CD200/CD200R between the antigen presenting cell (APC) (CHO cells stably expressing IE^k and CD200) and 2B4 Reay T cells expressing CD200R(1) with IL-2 production as the readout. (B) <b>Left panel</b>: flow cytometry plots showing IE^k expression on CHO-IE^k CD200 cells (tinted solid line) compared to untransfected CHO cells (dashed line). <b>Right panel</b>: flow cytometry plots showing CD200 mAb staining of CHO IE^k CD200 cells (tinted solid line) compared to isotype control (dashed line). (C) Effect of different mAb on IL-2 release. Either CHO-IE^k cells <b>(left panel)</b> or CHO-IE^k CD200 cells <b>(right panel)</b> were used together with CD200R(1) expressing T cells and IL-2 concentrations were measured. Effects of mAb were statistically compared with no mAb applied condition (representative of more than seven experiments). (D) Changes in IL-2 secretion from CD200R(1) 2B4 Reay cells in response to increasing doses of mAb. CHO-IE^k CD200 cells as APC. IL-2 levels obtained with OX90 and OX131 mAb were compared (representative of three experiments). (E) 10 µg/ml of OX110, OX131, OX132 (control) or no mAb were immobilized onto plates together with 0.5 µg/ml of CD3 mAb. CD200R(1) expressing 2B4 Reay cells were incubated overnight and IL-2 release in each condition was assayed. IL-2 levels obtained by each mAb stimulated condition were statistically compared with no mAb stimulated control. (representative of three experiments). Statistically significant (p<0.05) results were shown with asterix. (*) indicates p<0.05, (**) indicates p<0.01 and (***) indicates p<0.001 (C–E).