Cystatin F, a cysteine peptidase inhibitor, is a potent modulator of NK cytotoxicity. By inhibiting granule-mediated cytotoxicity pathway, cystatin F induces formation of non-functional NK cell... Show moreCystatin F, a cysteine peptidase inhibitor, is a potent modulator of NK cytotoxicity. By inhibiting granule-mediated cytotoxicity pathway, cystatin F induces formation of non-functional NK cell stage, called split-anergy. We show that N-glycosylation determines the localization and cellular function of cystatin F. Cystatin F mostly exhibited high-mannose glycosylation in U-937 cells, both high-mannose and complex glycosylation in NK-92 and primary NKs, and predominantly complex glycosylation in super-charged NKs. Manipulating N-glycosylation with kifunensine increased high-mannose glycosylation of cystatin F and lysosome localisation, which decreased cathepsin C activity and reduced NK cytotoxicity. Mannose-6-phosphate could significantly reduce the internalization of extracellular cystatin F. By comparing NK cells with different cytotoxic potentials, we found that high-mannose cystatin F was strongly associated with lysosomes and cathepsin C in NK-92 cell line. In contrast, in highly cytotoxic super-charged NKs, cystatin F with complex glycosylation was associated with the secretory pathway and less prone to inhibit cathepsin C. Modulating glycosylation to alter cystatin F localisation could increase the cytotoxicity of NK cells, thereby enhancing their therapeutic potential for treating cancer patients. Show less
Hees, E.P. van; Morton, L.T.; Remst, D.F.G.; Wouters, A.K.; Eynde, A. van den; Falkenburg, J.H.F.; Heemskerk, M.H.M. 2024
Background: NK cells can be genetically engineered to express a transgenic T-cell receptor (TCR). This approach offers an alternative strategy to target heterogenous tumors, as NK:TCR cells can... Show moreBackground: NK cells can be genetically engineered to express a transgenic T-cell receptor (TCR). This approach offers an alternative strategy to target heterogenous tumors, as NK:TCR cells can eradicate both tumor cells with high expression of HLA class I and antigen of interest or HLA class I negative tumors. Expansion and survival of NK cells relies on the presence of IL-15. Therefore, autonomous production of IL-15 by NK:TCR cells might improve functional persistence of NK cells. Here we present an optimized NK:TCR product harnessed with a construct encoding for soluble IL-15 (NK:TCR/IL-15), to support their proliferation, persistence and cytotoxic capabilities.Methods: Expression of tumor-specific TCRs in peripheral blood derived NK-cells was achieved following retroviral transduction. NK:TCR/IL-15 cells were compared with NK:TCR cells for autonomous cytokine production, proliferation and survival. NK:BOB1-TCR/IL-15 cells, expressing a HLA-B*07:02-restricted TCR against BOB1, a B-cell lineage specific transcription factor highly expressed in all B-cell malignancies, were compared with control NK:BOB1-TCR and NK:CMV-TCR/IL-15 cells for effector function against TCR antigen positive malignant B-cell lines in vitro and in vivo.Results: Viral incorporation of the interleukin-15 gene into engineered NK:TCR cells was feasible and high expression of the TCR was maintained, resulting in pure NK:TCR/IL-15 cell products generated from peripheral blood of multiple donors. Self-sufficient secretion of IL-15 by NK:TCR cells enables engineered NK cells to proliferate in vitro without addition of extra cytokines. NK:TCR/IL-15 demonstrated a marked enhancement of TCR-mediated cytotoxicity as well as enhanced NK-mediated cytotoxicity resulting in improved persistence and performance of NK:BOB1-TCR/IL-15 cells in an orthotopic multiple myeloma mouse model. However, in contrast to prolonged anti-tumor reactivity by NK:BOB1-TCR/IL-15, we observed in one of the experiments an accumulation of NK:BOB1-TCR/IL-15 cells in several organs of treated mice, leading to unexpected death 30 days post-NK infusion.Conclusion: This study showed that NK:TCR/IL-15 cells secrete low levels of IL-15 and can proliferate in an environment lacking cytokines. Repeated in vitro and in vivo experiments confirmed the effectiveness and target specificity of our product, in which addition of IL-15 supports TCR- and NK-mediated cytotoxicity. Show less
Sluijs, J.V. van der; Ens, D. van; Brummelman, J.; Heister, D.; Sareen, A.; Truijen, L.; ... ; Hobo, W. 2023
Allogeneic stem cell transplantation (alloSCT) can be curative for hemato-oncology patients due to effective graft-versus-tumor immunity. However, relapse remains the major cause of treatment... Show moreAllogeneic stem cell transplantation (alloSCT) can be curative for hemato-oncology patients due to effective graft-versus-tumor immunity. However, relapse remains the major cause of treatment failure, emphasizing the need for adjuvant immunotherapies. In this regard, post-transplantation dendritic cell (DC) vaccination is a highly interesting strategy to boost graft-versus-tumor responses. Previously, we developed a clinically applicable protocol for simultaneous large-scale generation of end-stage blood DC subsets from donor-derived CD34(+) stem cells, including conventional type 1 and 2 DCs (cDC1s and cDC2s), and plasmacytoid DCs (pDCs). In addition, the total cultured end-product (DC-complete vaccine), also contains non-end-stage-DCs (i.e. non-DCs). In this study, we aimed to dissect the phenotypic identity of these non-DCs and their potential immune modulatory functions on the potency of cDCs and pDCs in stimulating tumor-reactive CD8(+ )T and NK cell responses, in order to obtain rationale for clinical translation of our DC-complete vaccine. The non-DC compartment was heterogeneous and comprised of myeloid progenitors and (immature) granulocyte- and monocyte-like cells. Importantly, non-DCs potentiated toll-like receptor-induced DC maturation, as reflected by increased expression of co-stimulatory molecules and enhanced cDC-derived IL-12 and pDC-derived IFN-alpha production. Additionally, antigen-specific CD8(+) T cells effectively expanded upon DC-complete vaccination in vitro and in vivo. This effect was strongly augmented by non-DCs in an antigen-independent manner. Moreover, non-DCs did not impair in vitro DC-mediated NK cell activation, degranulation nor cytotoxicity. Notably, in vivo i.p. DC-complete vaccination activated i.v. injected NK cells. Together, these data demonstrate that the non-DC compartment potentiates DC-mediated activation and expansion of antigen-specific CD8+ T cells and do not impair NK cell responses in vitro and in vivo. This underscores the rationale for further clinical translation of our CD34+-derived DC-complete vaccine in hemato-oncology patients post alloSCT. Show less
Objective: To determine the effect of tetanus toxoid (TT) revaccination on circulating B-, T-and NK-cell com-partments in myasthenia gravis (MG) patients.Methods: Lymphocyte (sub)populations and... Show moreObjective: To determine the effect of tetanus toxoid (TT) revaccination on circulating B-, T-and NK-cell com-partments in myasthenia gravis (MG) patients.Methods: Lymphocyte (sub)populations and differentiation stages were assessed by flow cytometry in 50 TT revaccinated MG patients. TT-specific proliferative responses were explored in PBMC cultures. Results: In patients treated with azathioprine B-and NK cell numbers were strongly decreased. Lymphocyte (sub) populations remained unaffected upon TT revaccination. t All patients showed a significant TT-induced prolif-erative response.Conclusion: TT revaccination is effective in MG patients with stable disease irrespective of their thymectomy status and medication and does not alter the composition of the lymphocyte compartment. Show less
Gruijs, M.; Ganzevles, S.H.; Stigter-van Walsum, M.; Mast, R. van der; Ostaijen-ten Dam, M.M. van; Tuk, C.W.; ... ; Bakema, J.E. 2021
The immunosuppressive character of head and neck cancers may explain the relatively low response rates to antibody therapy targeting a tumor antigen, such as cetuximab, and anti-PD-1 checkpoint... Show moreThe immunosuppressive character of head and neck cancers may explain the relatively low response rates to antibody therapy targeting a tumor antigen, such as cetuximab, and anti-PD-1 checkpoint inhibition. Immunostimulatory agents that overcome tumor-derived inhibitory signals could augment therapeutic efficacy, thereby enhancing tumor elimination and improving patient survival. Here, we demonstrate that cetuximab treatment combined with immunostimulatory agonists for Toll-like receptor (TLR) 2 induces profound immune responses. Natural killer (NK) cells, isolated from healthy individuals or patients with head and neck cancer, harbored enhanced cytotoxic capacity and increased tumor-killing potential in vitro. Additionally, combination treatment increased the release of several pro-inflammatory cytokines and chemokines by NK cells. Tumor-bearing mice that received cetuximab and the TLR2 ligand Pam3CSK4 showed increased infiltration of immune cells into the tumors compared to mice that received cetuximab monotherapy, resulting in a significant delay in tumor growth or even complete tumor regression. Moreover, combination treatment resulted in improved overall survival in vivo. In conclusion, combining tumor-targeting antibody-based immunotherapy with TLR stimulation represents a promising treatment strategy to improve the clinical outcomes of cancer patients. This treatment could well be applied together with other therapeutic strategies such as anti-PD-(L)1 checkpoint inhibition to further overcome immunosuppression. Show less
Sluijs, J.V. van der; Ens, D. van; Thordardottir, S.; Vodegel, D.; Hermens, I.; Waart, A.B. van der; ... ; Hobo, W. 2021
Allogeneic stem cell transplantation (alloSCT), following induction chemotherapy, can be curative for hemato-oncology patients due to powerful graft-versus-tumor immunity. However, disease... Show moreAllogeneic stem cell transplantation (alloSCT), following induction chemotherapy, can be curative for hemato-oncology patients due to powerful graft-versus-tumor immunity. However, disease recurrence remains the major cause of treatment failure, emphasizing the need for potent adjuvant immunotherapy. In this regard, dendritic cell (DC) vaccination is highly attractive, as DCs are the key orchestrators of innate and adaptive immunity. Natural DC subsets are postulated to be more powerful compared with monocyte-derived DCs, due to their unique functional properties and cross-talk capacity. Yet, obtaining sufficient numbers of natural DCs, particularly type 1 conventional DCs (cDC1s), is challenging due to low frequencies in human blood. We developed a clinically applicable culture protocol using donor-derived G-CSF mobilized CD34(+) hematopoietic progenitor cells (HPCs) for simultaneous generation of high numbers of cDC1s, cDC2s and plasmacytoid DCs (pDCs). Transcriptomic analyses demonstrated that these ex vivo-generated DCs highly resemble their in vivo blood counterparts. In more detail, we demonstrated that the CD141(+)CLEG9A(+) cDC1 subset exhibited key features of in vivo cDC1s, reflected by high expression of co-stimulatory molecules and release of IL-12p70 and TNF-alpha. Furthermore, cDC1s efficiently primed alloreactive T cells, potently cross-presented long-peptides and boosted expansion of minor histocompatibility antigen-experienced T cells. Moreover, they strongly enhanced NK cell activation, degranulation and anti-leukemic reactivity. Together, we developed a robust culture protocol to generate highly functional blood DC subsets for in vivo application as tailored adjuvant immunotherapy to boost innate and adaptive anti-tumor immunity in alloSCT patients. Show less
The aim of this thesis was to better understand the underlying biology of tumor-immune interactions, especially in the circulation of CRC patients. The focus was primarily on the innate immune... Show moreThe aim of this thesis was to better understand the underlying biology of tumor-immune interactions, especially in the circulation of CRC patients. The focus was primarily on the innate immune system including NK cells, NKT cells, and macrophages. Show less
Vaccination strategies against mycobacteria, focusing mostly on classical T- and B-cells, have shown limited success, encouraging the addition of alternative targets. Classically restricted T-cells... Show moreVaccination strategies against mycobacteria, focusing mostly on classical T- and B-cells, have shown limited success, encouraging the addition of alternative targets. Classically restricted T-cells recognize antigens presented via highly polymorphic HLA class Ia and class II molecules, while donor-unrestricted T-cells (DURTs), with few exceptions, recognize ligands via genetically conserved antigen presentation molecules. Consequently, DURTs can respond to the same ligands across diverse human populations. DURTs can be activated either through cognate TCR ligation or via bystander cytokine signaling. TCR-driven antigen-specific activation of DURTs occurs upon antigen presentation via non-polymorphic molecules such as HLA-E, CD1, MR1, and butyrophilin, leading to the activation of HLA-E-restricted T-cells, CD1-restricted T-cells, mucosal-associated invariant T-cells (MAITs), and TCR gamma delta T-cells, respectively. NK cells and innate lymphoid cells (ILCs), which lack rearranged TCRs, are activated through other receptor-triggering pathways, or can be engaged through bystander cytokines, produced, for example, by activated antigen-specific T-cells or phagocytes. NK cells can also develop trained immune memory and thus could represent cells of interest to mobilize by novel vaccines. In this review, we summarize the latest findings regarding the contributions of DURTs, NK cells, and ILCs in anti-M tuberculosis, M leprae, and non-tuberculous mycobacterial immunity and explore possible ways in which they could be harnessed through vaccines and immunotherapies to improve protection against Mtb. Show less
Introduction: Natural killer (NK) cells and natural killer T (NKT) cells are implicated in the development and progression of colorectal cancer (CRC). Tumor cells express NK cell receptor ligands... Show moreIntroduction: Natural killer (NK) cells and natural killer T (NKT) cells are implicated in the development and progression of colorectal cancer (CRC). Tumor cells express NK cell receptor ligands that modulate their function. This study aimed to investigate the expression of such ligands in CRC in relation to the phenotype of circulating NK- and NKT cells, and clinical outcome.Methods: Primary tumor tissues were analyzed for protein expression of NK cell ligands using immunohistochemistry with automated image analysis in a cohort of 78 CRC patients. For 24 of the 78 patients, RNA expression of NK cell ligands was analyzed in primary tumor tissue using RNA sequencing. Receptor expression on circulating NK- and NKT cells was previously measured by us in 71 of the 78 patients using flow cytometry.Results: High Proliferating Cell Nuclear Antigen (PCNA) protein expression in the primary tumor associated with shorter disease-free survival (DFS) of CRC patients (P = 0.026). A trend was observed towards shorter DFS in CRC patients with above-median galectin-3 protein expression in the primary tumor (P = 0.055). High protein expression of galectin-3, CD1d, and human leukocyte antigen (HLA) class I, and high RNA expression of UL16-binding protein (ULBP)-1, -2, and -5, and HLA-E in the tumor tissue correlated with low expression of the corresponding receptors on circulating NK- or NKT cells (P < 0.05).Conclusions: Galectin-3 and PCNA expression in the primary tumor may be prognostic biomarkers in CRC patients. Furthermore, our results suggest that NK cell receptor ligands expressed by tumor cells may modulate the phenotype of circulating NK- and NKT cells, and facilitate immune escape of metastasizing cells. Show less
Elssen, C. van; Gorkom, G. van; Voorter, C.; Borne, P. von dem; Meijer, E.; Wieten, L.; Bos, G. 2020
Disease relapse is an important problem after allogeneic stem cell transplantations in multiple myeloma (MM). To test the hypothesis that natural killer (NK) cell alloreactivity in the setting of a... Show moreDisease relapse is an important problem after allogeneic stem cell transplantations in multiple myeloma (MM). To test the hypothesis that natural killer (NK) cell alloreactivity in the setting of a haploidentical stem cell transplantation (haploSCT) can reduce the risk of myeloma relapse, we performed a small prospective phase 2 study in which we transplanted poor-risk MM patients using a killer cell immunoglobulin-like receptor (KIR)-ligand mismatched haploidentical donor. Patients received bone marrow grafts after reduced-intensity conditioning, with post-transplantation cyclophosphamide (PTCY) graft-versus-host-disease (GVHD) prophylaxis. The primary endpoint was 1.5-year progression-free survival (PFS); stopping rules were installed in case interim results made a benefit of 50% PFS at 1.5 years unlikely. After inclusion of 12 patients, of which 9 were evaluable for the primary endpoint, all patients relapsed within a median time of 90 days. All except 1 patient showed engraftment, with a median time to neutrophil recovery of 18 (12-30) days. The study was prematurely terminated based on the predefined stopping rules after the inclusion of 12 patients. With this small study, we show that in chemo-resistant myeloma patients, NK cell KIR-mismatch is not superior to conventional alloSCT. This strategy, however, can serve as a platform for new treatment concepts. Clinical Trial Registry: NCT02519114 Show less
Hall, T. van; Andre, P.; Horowitz, A.; Ruan, D.F.; Borst, L.; Zerbib, R.; ... ; Vivier, E. 2019
Chimpanzees are the only animal species that can be infected with HIV-1. Infection kinetics in both humans and chimpanzees are similar, in contrast to humans, chimpanzees do not show any signs of... Show moreChimpanzees are the only animal species that can be infected with HIV-1. Infection kinetics in both humans and chimpanzees are similar, in contrast to humans, chimpanzees do not show any signs of immunodeficiency for many years. In this thesis specific aspects of the human and chimpanzee immune system are compared to unravel the differences in cellular immune responses in relation to HIV-1 infection. Human CD4 T-cells have less CD40L expression once the viral envelope is bound to the CD4 receptor. This is also seen in chimpanzees, but this occurs at a 5 fold higher antigen level, leading to the conclusion that chimpanzees are less sensitive for immunodeficiency. Little information is known about chimpanzee NK cells. The majority of this thesis describes the differences and overlaps between human and chimpanzee NK cells, with a focus on activatory receptors. Chimpanzee NK cells show small differences in the expression of these receptors, leading to the conclusion that these cells need more triggers than ligand binding, resulting in the hypothesis that chimpanzee NK cells are in less risk of over activation, which is seen in human lymphocytes. This overactivation leads to an exhausted immune system, which is thought to be the basis for immunodeficiency. Show less
