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

ABRATE, CAROLINA; BOSSIO, SABRINA N.; BOCCARDO, SANTIAGO; RODRIGEZ, CONSTANZA; GRUPPI, ADRIANA; RODRÍGUEZ, EVA V. ACOSTA; MONTES, CAROLINA L.

Tucumán

Congreso; LXVII Reunión Científica Anual de la Sociedad Argentina de Inmunología (SAI) 2019; 2019

We demonstrated that tumor-infiltrating exhausted CD8+T cells exhibit high expression of CD39. These cells are absent in draining lymph node (dLN). Here, we aimed to identify signals capable to trigger exhaustion and CD39 expression on CD8+T cells. Purified CD8+T cells from dLN of B16F10-OVA tumor-bearing mice were stimulated with αCD3/αCD28 in presence of IL-6 and/or IL-27 (48hs). Then, cells were resting in IL-2 (24hs) and re-stimulated with αCD3/αCD28 (24hs). TCR stimulation increased the frequency of CD39+T cells which is even higher in presence of IL-27 or IL-6 plus IL-27 (p≤0.05 for all). A similar pattern was observed for the expression of PD-1 and TIM-3, however IL-6 and IL-27 triggered an increment of the frequency 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) associated with exhaustion such as EOMES, IRF-4 and TBET. In addition, we found that CD39+CD8+T cells were able to maintain IL-2, TNF and INF-y production compare with CD39-CD8+T cells. We next evaluate the expression of iRs and TF in CD8+T cells from dLN of B16F10-OVA tumor bearing CD39KO mice stimulated following the protocol mentioned above. We observe that stimulated CD8+T cells from tumor-bearing CD39KO or WT mice show similar TFs and iRs expression. We conclude that TCR stimulation together with IL-6 or IL-27 trigger CD39 expression and phenotype associated to exhaustion. This phenomenon is not determined by the lack of CD39