Following HLA-DP-mismatched alloSCT and DLI, donor T cells show allogeneic (allo) HLA-DP-specific reactivity, resulting in a graft-versus-leukemia (GvL) effect with or without coinciding graft... Show moreFollowing HLA-DP-mismatched alloSCT and DLI, donor T cells show allogeneic (allo) HLA-DP-specific reactivity, resulting in a graft-versus-leukemia (GvL) effect with or without coinciding graft-versus-host disease (GvHD). The contribution of alloHLA-DP-specific T cells to the occurrence of GvL and GvHD may depend on several factors including the expression of HLA-DP on hematopoietic and non-hematopoietic patient cells and the magnitude of the allo-HLA-DP-specific immune responses. The magnitude of the allo-HLA-DP-specific immune responses provoked by HLA-DP-mismatched antigen-presenting cells (APC) is influenced by the immunogenicity of the mismatched target HLA-DP allele(s) and the specificity and diversity of allo-HLA-DP-specific T-cell repertoires. In this thesis, we investigated in vitro the composition of allo-HLA-DP-specific T-cell repertoires and the magnitude and diversity of allo-HLA-DP-specific immune responses provoked under different stimulatory conditions. Show less
Laghmouchi, A.; Kester, M.G.D.; Hoogstraten, C.; Hageman, L.; Klerk, W. de; Huisman, W.; ... ; Jedema, I. 2022
In the context of HLA-DP-mismatched allogeneic stem cell transplantation, mismatched HLA-DP alleles can provoke profound allo-HLA-DP-specific immune responses from the donor T-cell repertoire... Show moreIn the context of HLA-DP-mismatched allogeneic stem cell transplantation, mismatched HLA-DP alleles can provoke profound allo-HLA-DP-specific immune responses from the donor T-cell repertoire leading to graft-versus-leukemia effect and/or graft-versus-host disease in the patient. The magnitude of allo-HLA-DP-specific immune responses has been shown to depend on the specific HLA-DP disparity between donor and patient and the immunogenicity of the mismatched HLA-DP allele(s). HLA-DP peptidome clustering (DPC) was developed to classify the HLA-DP molecules based on similarities and differences in their peptide-binding motifs. To investigate a possible categorization of HLA-DP molecules based on overlap of presented peptides, we identified and compared the peptidomes of the thirteen most frequently expressed HLA-DP molecules. Our categorization based on shared peptides was in line with the DPC classification. We found that the HLA-DP molecules within the previously defined groups DPC-1 or DPC-3 shared the largest numbers of presented peptides. However, the HLA-DP molecules in DPC-2 segregated into two subgroups based on the overlap in presented peptides. Besides overlap in presented peptides within the DPC groups, a substantial number of peptides was also found to be shared between HLA-DP molecules from different DPC groups, especially for groups DPC-1 and -2. The functional relevance of these findings was illustrated by demonstration of cross-reactivity of allo-HLA-DP-reactive T-cell clones not only against HLA-DP molecules within one DPC group, but also across different DPC groups. The promiscuity of peptides presented in various HLA-DP molecules and the cross-reactivity against different HLA-DP molecules demonstrate that these molecules cannot be strictly categorized in immunogenicity groups. Show less
Laghmouchi, A.; Hoogstraten, C.; Falkenburg, J.H.F.; Jedema, I. 2020
Magnetic-activated cell sorting (MACS) using magnetic nanoparticles coated with specific antibodies is commonly used in immunology research. For in vitro isolation purposes, it is important to know... Show moreMagnetic-activated cell sorting (MACS) using magnetic nanoparticles coated with specific antibodies is commonly used in immunology research. For in vitro isolation purposes, it is important to know to what extent the magnetic properties remain present in the isolated cell populations and whether it has consequences for sequential isolations. We hypothesized that only upon cell division, cells will lose their magnetic properties via dilution of the particles in/on their daughter cells. We analysed residual magnetic properties of cells that divided vs cells that did not divide after magnetic bead-based cell separation. As a model, we isolated T cells using beads targeting the non-modulating surface molecule CD45RO. Cells were labelled with the cell division tracking dye PKH and cultured under different conditions to induce variable degrees of cell division. We demonstrate that T cells that underwent no, or only minimal, cell divisions after MACS retained magnetic properties for up to at least 2 weeks of in vitro culture. The presence of nanoparticles was detected on their cell surface and intracellularly using Labeling Check reagent. These results have important consequences for procedures requiring repetitive isolation rounds after in vitro culture. Show less
Laghmouchi, A.; Hoogstraten, C.; Falkenburg, J.H.F.; Jedema, I. 2020
Allogeneic (allo) stem cell transplantation is applied to patients suffering from hematologic malignancies to replace the diseased hematopoietic system with cells derived from a donor stem cell... Show moreAllogeneic (allo) stem cell transplantation is applied to patients suffering from hematologic malignancies to replace the diseased hematopoietic system with cells derived from a donor stem cell graft. The majority of 10/10matched unrelated donors are HLA-DP-mismatched, and this may result in varying degrees of the graft-versusleukemia (GVL) effect with or without the occurrence of graft-versus-host disease (GVHD). Allo-HLA-reactive T cells are commonly present in the donor T cell repertoire, and thus a very profound alloreactive immune response can be provoked in the HLA-DP-mismatched setting. The magnitude and the diversity of the allo-HLA-DP-specific immune response likely dictates the balance between the occurrence of GVL and/or GVHD after transplantation. To understand the nature of the allo-HLA-DP-specific immune response provoked under different stimulatory conditions, immune responses were induced from both the naive and memory T cell compartments using either HLA-DP-mismatched professional antigen-presenting cells (APCs) (monocyte-derived dendritic cells [allo-DCs]) or HLA-DP-mismatched nonprofessional APCs (skin-derived fibroblasts [allo-fibroblasts]) as stimulator cells. In this study, we observed that allo-HLA-DP-reactive T cells could be provoked from both the naive and memory compartments by both types of APCs. However, the magnitude of the allo-HLA-DP-specific immune response was greater when stimulation was performed with allo-DCs. Moreover, we found that the frequency of allo-HLA-DPreactive T cells was greater in the naive T cell compartment compared with the memory T cell compartment, but we observed a comparable lineage specificity of these allo-HLA-DP-specific reactivities. Overall, the data from this study illustrate that the presence of professional APCs of recipient origin will mostly dictate the magnitude of the allo-HLA-DP-specific immune response derived from both the naive and memory T cell compartments, but does not exclusively mediate the induction of these immune responses. (C) 2020 American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. Show less
Laghmouchi, A.; Hoogstraten, C.; Balen, P. van; Falkenburg, J.H.F.; Jedema, I. 2019
