Tumor‐reactive CD4⁺CD8αβ⁺ CD103⁺ αβT cells: A prevalent tumor‐reactive T‐cell subset in metastatic colorectal cancers

Abstract

High level of T-cell infiltration in colorectal carcinomas (CRCs) is a good prognostic indicator, but the tumor reactivity of this infiltrate (tumor infiltrating lymphocytes [TIL]) is poorly documented. This study examined the presence, phenotype and functional features of tumor-reactive lymphocytes in human CRC. Freshly dissociated TIL and T cell lines were isolated from CRC samples and from some paired normal colonic mucosa. Four tumor cell lines were obtained. Autologous tumor reactivity of CRC TIL and tumor-reactive cell features were analyzed. We demonstrate the presence among CRC TIL of variable fractions (up to 18%) of double positive CD4 1 CD8ab 1 (DP) ab T cells. Interestingly, a high proportion (16-20%) of this TIL subset displayed tumor reactivity, whilst this was the case for no or few single positive TIL. Low levels of DP TIL were found in most CRC samples and in normal colonic mucosa, but these cells were higher in metastatic CRC. Furthermore, we showed that DP TIL were polyclonal, restricted by HLA class-I, proliferated poorly and secreted higher amounts of IL-4 and IL-13 than single positive T cells, on cognate or CD3 stimulation. DP CRC TIL also expressed CD103, confirming their mucosal origin. Increased frequencies of tumor-reactive DP TIL in metastatic CRC suggest that these cells play a role in the metastatic process of this cancer. Based on their high secretion of IL-4 and IL-13 and on previously described roles of these cytokines in cancers, we postulate that DP TIL could favor CRC growth or metastasis and/or downmodulate immune responses to these tumors.Recent studies have highlighted the high prognostic value of the density of T cells infiltrating colorectal carcinomas (CRC), implying an important contribution of T-cell responses to the control of this cancer. 1 Nonetheless, contrary to other cancers such as melanomas, 2 evidence that CRC may induce tumor-specific T-cell responses in an autologous setting is still scarce. 3 This may be due to the difficulty in obtaining stable CRC cell lines required for the detection of T cells specific to individual tumor antigens such as frameshift mutations. 4 Alternatively, it might result from the presence of qualitatively unique T-cell responses in this cancer, which has not yet been appropriately addressed.We previously reported that CRC-reactive c9d2 T cells were present in several CRC ascites. 5 The aim of the present study was to analyze the presence of conventional and unconventional tumor-reactive ab T cells, such as CD4 þ CD8 þ double positive cells (DP), in a significant series of CRC.As reviewed by Parel et al., 6 DP T lymphocytes account for a small and heterogeneous subset of TCRab cells. At present, three subsets of these cells could be distinguished: (i) conventional CD8 þ T cells that on activation express low CD4 levels; (ii) conventional CD4 þ T cells that acquire longterm CD8aa expression in vivo, as a result of exposure to unknown factors associated with the intestinal environment, aging or HIV infection and (iii) T cells stably e...

IL‐9 promotes the survival and function of human melanoma‐infiltrating CD4+CD8+ double‐positive T cells

“…To date, the lack of unequivocal studies prevents the establishment of a consensus regarding DP T-cell origin, phenotype and function for a given pathological context. Thus, DP T cells require individual consideration on a case-by-case basis.In cancer, DP T cells have been initially reported in lymphomas as cutaneous T-cell lymphomas [26][27][28] and nodular lymphocyte predominant Hodgkin lymphoma [29] where they were described as a CD4 high CD8 low DP T-cell population with cytotoxic activity [26].Besides, we documented the presence of CD4 low CD8αβ high DP T cells at a high frequency, among tumor-infiltrating lymphocytes (TILs) of several solid human tumors (breast carcinomas, melanomas, and colorectal carcinomas) [25,30,31]. Moreover, the prevalence of DP T cells in distant cutaneous metastasis was significantly higher (p < 0.05) than in lymph node metastasis and even higher (p < 0.01) than in blood from patients or healthy donors, suggesting an association between DP T-cell frequency and both tumor microenvironment and cancer progression.…”

“…In these contexts, diverse functions of DP T cells were observed from cytotoxic activity [22,24] to regulatory properties [25], as well as helper potential [10]. To date, the lack of unequivocal studies prevents the establishment of a consensus regarding DP T-cell origin, phenotype and function for a given pathological context.…”

“…Besides, we documented the presence of CD4 low CD8αβ high DP T cells at a high frequency, among tumor-infiltrating lymphocytes (TILs) of several solid human tumors (breast carcinomas, melanomas, and colorectal carcinomas) [25,30,31]. Moreover, the prevalence of DP T cells in distant cutaneous metastasis was significantly higher (p < 0.05) than in lymph node metastasis and even higher (p < 0.01) than in blood from patients or healthy donors, suggesting an association between DP T-cell frequency and both tumor microenvironment and cancer progression.…”

Metformin inhibits melanoma development through autophagy and apoptosis mechanisms

“…Patient melanoma cells were prepared as described. 37 Briefly, biopsy was dissected and digested for 1–2 h with collagenase A (0.33 U/ml), dispase (0.85 U/ml) and Dnase I (144 U/ml) with rapid shaking at 37°C. Large debris were removed by filtration through a 70- μ m cell strainer.…”

CD40L confers helper functions to human intra-melanoma class-I-restricted CD4+CD8+double positive T cells

“…An efficient cytolytic activity was attributed to the CD4 high CD8 low DP T-cell subset found in lymphoma 21 . Conversely, in solid tumors, we reported at least two different phenotypic DP T-cell subsets, the CD4 low CD8 high DP T-cell subpopulation in melanoma and breast cancer 22,23 and the CD4 high CD8 high DP T-cell subpopulation in colorectal cancer, 25 both sharing the CD8αβ dimer.…”