CD8+ T cells up-regulate CD39 expression and inhibitory receptors upon in vitro TCR and cytokines stimulation.

ABRATE C; BOSSIO SN; CANALE F; BOCCARDO S; RODRIGUEZ C; GRUPPI A; ACOSTA RODRIGUEZ EV; MONTES CL

Congreso; SAIC-SAI-SAFIS 2018.; 2018

Previously we have shown that the frequency of exhaustedCD39highCD8+ T cells increased with tumor growth but was absentin lymphoid organs. We aimed to evaluate signals that mayinfluence CD39 and inhibitory receptors (IRc) upregulation on CD8+T cells. Purified CD8+ T cells from draining lymph node of B16F10-OVA tumor bearing mice were stimulated during 48hs with αCD3/αCD28 in presence or absence of IL-6 or conditioned medium (CM)obtained by culturing tumors from B16F10-OVA bearing mice. Thencells were resting in IL-2 (96hs) and re-stimulated with αCD3/αCD28(24hs). We observed that after TCR stimulation, the frequency ofCD39+ and PD-1+TIM-3+ CD8+T cells were (27.3%±8.1% and50.57%±0.46% respectively), however the frequency of both populationswas not increase by neither MC nor IL-6. Next we stimulatedthe CD8+ T cells reducing the resting with IL-2 (24hs) in presenceor absence of IL-6, IL-27 or CM. We found that TCR stimulation increasedsignificantly the % of CD39+CD8+ T cells (p≤0.05) respectto non-stimulated cells, and the frequency of the CD39+ expressingcells decreased in absence of IL-2 (p≤0.05). The stimulation withcytokines associated with exhaustion such as IL-27 or a combinationof IL-6/IL-27 increased the frequency of CD39+ cells (p<0.01 forboth), while this frequency was not modified in presence of IL-6 orCM respect to TCR-stimulated control cells. Upon TCR stimulationthe % of both PD-1+ and TIM-3+ cells increased significantly respectto non-stimulated cells (p≤0.0001 and p≤0.01 respectively), howeveronly IL-6 plus TCR stimulation triggered an increment of PD-1+T cells frequency (p≤0.05). We showed that TCR stimulation induceCD39 on murine CD8+ T cells which is more evident when combiningIL-6 and IL-27, indicating that CD39 expression may result as aconsequence of the integration of different signals.