Lation (data not shown). Considering the fact that T cells utilize IL-2 to sustain their development, we examined irrespective of whether the inhibitory impact of PAG on IL-2 secretion was the basis for the reduction in their CEACAM1 Proteins Purity & Documentation proliferation (Fig. 3G). To this end, T cells were stimulated with anti-CD3 alone or in combination with anti-CD28, in the presence or inside the absence of exogenous IL-2. Proliferation was then measured as described earlier. We located that addition of IL-2 only partially corrected the inhibitory impact of PAG on proliferation. Hence, while part of the inhibitory impact of PAG on proliferation can be ascribed to reduced IL-2 production, it truly is probably that additional aspects are also involved. Inhibition of proximal TCR-mediated signaling events by PAG. To establish the biochemical mechanism responsible for PAG-mediated inhibition, we assessed the impact of PAG onVOL. 23,REGULATION OF T-CELL