Abstract 4044: Draining lymph nodes in ovarian cancer patients have a naïve immune cell signature

Abstract

Abstract Purpose: Ovarian cancer (OC) is characterized by an immunosuppressive tumor micro-environment (TME). We speculated that the effects of this immunosuppressive TME extends to the draining lymph nodes (DLNs), hampering induction of a proper anti-tumor immune response. To address this, we compared the immune cell composition in OC tumors and DLNs using extensive flow cytometry. Experimental design: OC tumor (n=16) and DLN samples (n=13) were collected during surgery after obtaining informed consent from the patients. All tissue samples were subjected to enzymatic digestion and single cells were isolated by density gradient centrifugation. Eight-color flow cytometry panels were used to cover various T cell and myeloid cell markers. Statistical analysis was performed as appropriate. Results: CD8+ cytotoxic T cells (p<0.001) and T regulatory cells (Tregs, p<0.05) were significantly enriched in the tumor compared to the DLNs, while there were more CD4+ T helper cells in the DLNs (p<0.001). Interestingly, CD123+ plasmocytoid dendric cells (DCs) were largely absent from the tumor, whereas CD1a+ CD1c+ immature DCs (p<0.001) were enriched in the TME. No difference between the tumor and DLNs was seen for CD11c+ myeloid DCs (mDC). However, within the mDC population there were more CD1c+ myeloid type 1 DC (p<0.05) in the DLNs than tumor, but less CD1a+ myeloid type 2 DCs (p<0.001), no difference was seen for iDCs. Tumoral T cells had an exhausted effector memory T cell signature, upregulating HLA-DR, the memory T cell marker CD45RO and the T cell suppressing and exhaustion markers, PD-1, PD-L1, and CD27. Notably, tumoral CD4+ T cells highly expressed the co-stimulatory markers CD28 and OX40. In the DLNs, all T cells were predominantly CD45RA+ CCR7+ naïve T cells, concurrently expressing CD27 and CD28. In the tumor and DLNs, Tregs highly expressed CTLA-4 and ICOS, while CD8+ and CD4+ T cells heterogeneously expressed these markers. The proliferation marker Ki67+ was expressed by tumoral T cells and by all Tregs. The transcription factor EOMES was mainly expressed by Ki67+ CD8+ T cells, while the transcription factor Tbet was expressed by CD8+ T cells, independent of Ki67-expression or location in tumor or DLN. DLNs were largely devoid of Ki67+ T cells, with the exception of Tregs. Conclusions: Cancer can elicit an antigen-mediated immune response via the DLN. However, our data shows a naïve immune cell composition in the DLNs of OC, possibly due to the immunosuppressive effects of the TME extending to the DLNs. Citation Format: Kim Brunekreeft, Fenne Komdeur, Hagma Workel, Florine Eggink, Annechien Plat, Refika Yigit, Harry Hollema, Evelien Duiker, Hans Nijman, Marco Bruyn. Draining lymph nodes in ovarian cancer patients have a naïve immune cell signature [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4044.