TCR and cytokines stimulation trigger CD39 expression and a phenotype associated to exhaustion in CD8+ T cells.

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

Congreso; LXVII Reunión Anual de la SAI; 2019

We demonstrated that tumor-infiltrating exhausted CD8+T cells exhibit high expression ofCD39. These cells are absent in draining lymph node (dLN). Here, we aimed to identify signalscapable to trigger exhaustion and CD39 expression on CD8+T cells. Purified CD8+T cells fromdLN of B16F10-OVA tumor-bearing mice were stimulated with αCD3/αCD28 in presence of IL6 and/or IL-27 (48hs). Then, cells were resting in IL-2 (24hs) and re-stimulated withαCD3/αCD28 (24hs). TCR stimulation increased the frequency of CD39+T cells which is evenhigher in presence of IL-27 or IL-6 plus IL-27 (p≤0.05 for all). A similar pattern was observedfor the expression of PD-1 and TIM-3, however IL-6 and IL-27 triggered an increment of thefrequency of PD-1+ and TIM-3+ respectively, respect to TCR-stimulated T cells (p≤0.05 for all).Interestingly these CD39+CD8+T cells exhibited co-expression of 2 or 3 inhibitory receptors(iRs): LAG-3, PD-1 and TIM-3. CD39+CD8+T cells express transcriptions factors (TF) associatedwith exhaustion such as EOMES, IRF-4 and TBET. In addition, we found that CD39+CD8+T cellswere able to maintain IL-2, TNF and INF-y production compare with CD39-CD8+T cells. Wenext evaluate the expression of iRs and TF in CD8+T cells from dLN of B16F10-OVA tumorbearing CD39KO mice stimulated following the protocol mentioned above. We observe thatstimulated CD8+T cells from tumor-bearing CD39KO or WT mice show similar TFs and iRsexpression. We conclude that TCR stimulation together with IL-6 or IL-27 trigger CD39expression and phenotype associated to exhaustion. This phenomenon is not determined bythe lack of CD39.