CD39+ CD4+ T conventional cells accumulate within tumors and invaded lymph nodes from breast cancer patients and exhibit features of exhaustion.

BOSSIO, SABRINA N.; BOARI, JIMENA TOSELLO; ABRATE, CAROLINA; RAMELLO, MARÍA C.; CANALE, FERNANDO P.; GRUPPI, ADRIANA; ACOSTA RODRÍGUEZ, E.V.; PIAGGIO, ELIANE; MONTES, CAROLINA L.

Congreso; Congreso Anual de la Sociedad Argentina de Inmunología 2022.; 2022

The role of CD4+ T cells in the immune response against tumors is not completely elucidated. In this work, by flow cytometry, we explored the distribution of CD4+ T cells in tumor, adjacent non-tumoral mammary tissues (yuxtatumor) and metastatic and non-metastatic draining lymph nodes (dLNs) from untreated breast cancer (BC) patients. We first evaluated the presence of LiTreg (CD4+FOXP3+) and CD4+ conventional T lymphocytes (LiTconv) (CD4+FOXP3-) in primary tumors matched with non-tumoral mammary tissues. As previously described, tumors exhibited higher infiltration of LiTreg, than yuxtatumor. However, CD4+ infiltrating tumors and yuxtatumors are composed of a majority of LiTconv. Surprisingly, we detected that tumors exhibited higher % of CD39+ expressing LiTconv compared to yuxtatumor (p≤0.01). We observed that while CD39+ LiTconv were absent in peripheral blood, the % in metastatic dLNs was significantly higher than in non-metastatic dLNs (p≤0.05). The phenotypic analysis of tumor-infiltrating (TI) LiTconv population revealed that, within CD39+ population, there were higher frequency of PD-1+, TIGIT+ and BTLA+ cells compared to the CD39- population (p≤0.01). The effector function of TI-CD39+ LiTconv was assessed analyzing their ability to produce TNF, IFN and IL-2. Thus, TI-CD39+ LiTconv exhibited a lower frequency of TNF-producing cells than CD39- LiTconv (p≤0.05) and a higher frequency of CD107a+ cells (p≤0.05). There were no significant differences in IFN and IL-2 production between CD39+ and CD39- LiTconv. In vitro stimulation of sorted TI-CD39- LiTconv with anti-CD3/anti-CD28 from 5 BC patients, showed an increased frequency of CD39+ cells upon 72 hs of stimulation. This result highlights the relevance of the TCR-stimulation in the CD39 expression. Together these findings suggest that tumor microenvironment drives the acquisition of immunoregulatory molecules on LiTconv which may impact in tumor progression.