Background Expression of CD103 and CD39 has been found to pinpoint tumor-reactive CD8+ T cells in a variety of solid cancers. We aimed to investigate whether these markers specifically identify... Show moreBackground Expression of CD103 and CD39 has been found to pinpoint tumor-reactive CD8+ T cells in a variety of solid cancers. We aimed to investigate whether these markers specifically identify neoantigen-specific T cells in colorectal cancers (CRCs) with low mutation burden.Experimental design Whole-exome and RNA sequencing of 11 mismatch repair-proficient (MMR-proficient) CRCs and corresponding healthy tissues were performed to determine the presence of putative neoantigens. In parallel, tumor-infiltrating lymphocytes (TILs) were cultured from the tumor fragments and, in parallel, CD8+ T cells were flow-sorted from their respective tumor digests based on single or combined expression of CD103 and CD39. Each subset was expanded and subsequently interrogated for neoantigen-directed reactivity with synthetic peptides. Neoantigen-directed reactivity was determined by flow cytometric analyses of T cell activation markers and ELISA-based detection of IFN-γ and granzyme B release. Additionally, imaging mass cytometry was applied to investigate the localization of CD103+CD39+ cytotoxic T cells in tumors.Results Neoantigen-directed reactivity was only encountered in bulk TIL populations and CD103+CD39+ (double positive, DP) CD8+ T cell subsets but never in double-negative or single-positive subsets. Neoantigen-reactivity detected in bulk TIL but not in DP CD8+ T cells could be attributed to CD4+ T cells. CD8+ T cells that were located in direct contact with cancer cells in tumor tissues were enriched for CD103 and CD39 expression.Conclusion Coexpression of CD103 and CD39 is characteristic of neoantigen-specific CD8+ T cells in MMR-proficient CRCs with low mutation burden. The exploitation of these subsets in the context of adoptive T cell transfer or engineered T cell receptor therapies is a promising avenue to extend the benefits of immunotherapy to an increasing number of CRC patients. Show less
Korporaal, S.J.A.; Sluis, R.J. van der; Eck, M. van; Hoekstra, M. 2021
The genetic disorder Down syndrome is associated with a decreased susceptibility for atherosclerotic cardiovascular disease. Hematological and immune abnormalities occur frequently in Down syndrome... Show moreThe genetic disorder Down syndrome is associated with a decreased susceptibility for atherosclerotic cardiovascular disease. Hematological and immune abnormalities occur frequently in Down syndrome patients. We evaluated, in a preclinical setting, the impact of a Down syndrome-like hematological/immune phenotype on atherosclerosis susceptibility. Hereto, hypercholesterolemic low-density lipoprotein receptor knockout mice were transplanted with bone marrow from either a trisomic Ts65Dn mouse or euploid wild-type control and subsequently fed a Western-type diet to induce the development of atherosclerotic lesions. T and B cell concentrations were markedly reduced in blood of Ts65Dn bone marrow recipients (p < 0.001). Expression levels of the pro-atherogenic scavenger receptor CD36 were respectively 37% and 59% lower (p < 0.001) in trisomic monocytes and macrophages. However, these combined effects did not translate into an altered atherosclerosis susceptibility. Notably, blood platelet numbers were elevated in Ts65Dn bone marrow recipients (+57%; p < 0.001), which was paralleled by higher platelet GPVI protein expression (+35%; p < 0.001) and an enhanced collagen-induced platelet activation (p < 0.001). In conclusion, we have shown that providing mice with a Down syndrome-like hematological profile does not change the susceptibility to atherosclerosis. Furthermore, our studies have uncovered a novel effect of the trisomy on platelet functionality that may be relevant in human clinical settings. Show less
Dammeijer, F.; Gooijer, C.J. de; Gulijk, M. van; Lukkes, M.; Klaase, L.; Lievense, L.A.; ... ; Aerts, J.G. 2021
Background: Gemcitabine is a frequently used chemotherapeutic agent but its effects on the immune system are incompletely understood. Recently, the randomized NVALT19-trial revealed that... Show moreBackground: Gemcitabine is a frequently used chemotherapeutic agent but its effects on the immune system are incompletely understood. Recently, the randomized NVALT19-trial revealed that maintenance gemcitabine after first-line chemotherapy significantly prolonged progression-free survival (PFS) compared to best supportive care (BSC) in malignant mesothelioma. Whether these effects are paralleled by changes in circulating immune cell subsets is currently unknown. These analyses could offer improved mechanistic insights into the effects of gemcitabine on the host and guide development of effective combination therapies in mesothelioma.Methods: We stained peripheral blood mononuclear cells (PBMCs) and myeloid-derived suppressor cells (MDSCs) at baseline and 3 weeks following start of gemcitabine or BSC treatment in a subgroup of mesothelioma patients included in the NVALT19-trial. In total, 24 paired samples including both MDSCs and PBMCs were included. We performed multicolour flow-cytometry to assess co-inhibitory and-stimulatory receptor- and cytokine expression and matched these parameters with PFS and OS.Findings: Gemcitabine treatment was significantly associated with an increased NK-cell- and decreased T-regulatory cell proliferation whereas the opposite occurred in control patients. Furthermore, myeloid derived suppressor cells (MDSCs) frequencies were lower in gemcitabine-treated patients and this correlated with increased T-cell proliferation following treatment. Whereas gemcitabine variably altered co-inhibitory receptor expression, co-stimulatory molecules including ICOS, CD28 and HLA-DR were uniformly increased across CD4(+) T-helper, CD8(+) Tand NK-cells. Although preliminary in nature, the increase in NK-cell proliferation and PD-1 expression in T cells following gemcitabine treatment was associated with improved PFS and OS.Interpretation: Gemcitabine treatment was associated with widespread effects on circulating immune cells of mesothelioma patients with responding patients displaying increased NK-cell and PD-1 + T-cell proliferation. These exploratory data provide a platform for future on treatment-biomarker development and novel combination treatment strategies. (C) 2020 The Authors. Published by Elsevier B.V. Show less
Cardiovascular disease is a major global burden and atherosclerosis is the main underlying pathological process. Despite better management of cholesterol levels, there remains a significant... Show moreCardiovascular disease is a major global burden and atherosclerosis is the main underlying pathological process. Despite better management of cholesterol levels, there remains a significant residual risk of developing atherosclerosis and cardiovascular events. Hence, novel pathways and targets should be identified to optimize atherosclerosis therapy. Despite dyslipidemia, the immune system is also heavily involved in the pathophysiology of atherosclerosis. Protective immune responses in the acute setting of increased cholesterol levels eventually turn into debilitating responses when the immune system is chronically stimulated. Hence, we aimed to identify new therapeutic targets to dampen the immune response in atherosclerosis. More specifically, we focused our efforts on modulating the B lymphocyte response, for which there was a scarcity of data. In this thesis we describe novel ways to modulate the B cell response in atherosclerosis. We have found that there are specific B cell subsets that have different effects on the progress of atherosclerosis. For instance, removal of TIM-1+ B cells resulted in increased atherosclerosis, while removal of BTLA+ follicular B cells reduced atherosclerosis. In conclusion, this thesis provides promising immunological targets for the treatment of atherosclerosis. Show less
Snip, O.S.C.; Hoekstra, M.; Zhao, Y.; Calpe-Berdiel, L.; Vulve, J.; Carles Escola-Gil, J.; ... ; Eck, M. van 2018
Various studies have shown that leukocyteATP-binding cassette transporter A1 (ABCA1) is an anti-atherogenic factor. It has long been assumed that the increased atherosclerosis susceptibility... Show moreVarious studies have shown that leukocyteATP-binding cassette transporter A1 (ABCA1) is an anti-atherogenic factor. It has long been assumed that the increased atherosclerosis susceptibility observed in leukocyte ABCA1 deficient hyperlipidemic mice was due to an accelerated foam cell formation. However, several studies have suggested that leukocyte ABCA1 may also have a beneficial effect on systemic inflammation. In this study we aim to determine the effect of leukocyte ABCA1 deficiency on atherosclerosis susceptibility in mice that are apolipoprotein A1 (apoA1) deficient.To determine the impact of leukocyte ABCA1 on atherosclerosis outcome, lethally irradiated low-density lipoprotein receptorknock-out (sKO) mice or LDLr/apoA1 double KO (dKO) mice were reconstituted with either ABCA1 KO or wild-type bone marrow. All four groups of chimeric mice were fed a Western-type diet for 6 weeks to induce atherosclerotic lesion development.Leukocyte ABCA1 deficiency in dKO mice resulted in 50-70% larger lesions in the aortic root than those observed in both sKO mice transplanted with ABCA1 KO bone marrow and dKO mice transplanted with wild-type bone marrow. Furthermore, total leukocyte numbers in blood were generally higher in mice lacking apoA1 as compared to those containing apoA1-carrying HDL particles. Two way ANOVA on the different white blood cell sub-populations suggested that the apoA1 deficiency-associated increase in total leukocyte counts was driven by an increase in the number of lymphocytes (P<0.001) and, to a minor extent, monocytes (P<0.01).This study shows that reduced systemic inflammation and increased reverse cholesterol transport together drive macrophage ABCA1-mediated protection against atherosclerosis. Show less
Gezgin, G.; Dogrusoz, M.; Essen, T.H. van; Kroes, W.G.M.; Luyten, G.P.M.; Velden, P.A. van der; ... ; Jager, M.J. 2017
