PHENOTYPIC AND FUNCTIONAL CHARACTERIZATION OF CD39+CD4+ CONVENTIONAL T LYMPHOCYTES FROM B16F10-OVA TUMOR-BEARING MICE

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

Buenos Aires

Congreso; Reunión Conjunta de Sociedades de Biomedicina. Buenos Aires. 13-17 Noviembre.2017; 2017

Sociedades biomedicas argentinas

The enzymatic activities of CD39 and CD73 play key roles inthe modulation of signals delivered in the tumor microenvironment(TME) through the conversion of ADP/ATP to adenosine. We aimedto study the expression of CD39 on conventional Foxp3- CD4+ Tcells (Tconv) from tumor-bearing mice by flow cytometry. C57BL/6mice were injected with B16F10-OVA cancer cells. Tumors, spleensand draining lymph nodes (dLN) were extracted on day 17. Weobserved increased frequency of CD39CD73-expressing Tconv intumor respect to spleen (p≤0.001) and dLN (p≤0.001). This population,together with CD39-CD73+ Tconv showed higher expressionof CD26 compared to CD73- Tconv. In tumors, we detectedthat 18,5±2,6% of CD39+ Tconv co-express PD-1 and LAG-3, and15,8±6,6% express TIGIT. In addition, PD-L1 expression was increasedon this population compared to CD39- Tconv (p≤0.01). Weobserved that 89,4±2,7% of tumor-infiltrating CD39+ Tconv exhibitedeffector memory phenotype. Around 50% of this cells were CD49d+CD11a+, a phenotype associated with antigenic stimulation. The efector function of these cells was assessed analyzing their abilityto produce cytokines upon activation. Within CD39+ Tconv we detecteddecreased frequency of TNF-producing cells, but higher frequencyof IFNγ-producing cells compared to CD39- Tconv (p≤0.01for all). In concordance, CD39+ Tconv showed high expression ofT-bet. Also, CD39+ Tconv exhibited higher frequency of CD107a+and Granzyme B+ cells than their CD39- counterparts. CD39+Tconvdid not produce IL-2. Using Hypoxyprobe-1 reagent, we found ahigher frequency of hypoxic cells within the subset CD39+ Tconvcompared to CD39- Tconv (p≤0.01). Together these results suggestthat TME drives the acquisition of immunoregulatory molecules onTconv and postulate CD39 as a relevant target to be deeply studiedin order to understand how this molecule expressed on Tconv mayinfluence the anti-tumor immune response.