| 31. |
- Frisk, Thomas, et al.
(författare)
-
A silicon-glass microwell platform for high-resolution imaging and high-content screening with single cell resolution
- 2011
-
Ingår i: Biomedical microdevices (Print). - : Springer Science and Business Media LLC. - 1387-2176 .- 1572-8781. ; 13:4, s. 683-693
-
Tidskriftsartikel (refereegranskat)abstract
- We present a novel microwell array platform suited for various cell-imaging assays where single cell resolution is important. The platform consists of an exchangeable silicon-glass microchip for cell biological applications and a custom made holder that fits in conventional microscopes. The microchips presented here contain arrays of miniature wells, where the well sizes and layout have been designed for different applications, including single cell imaging, studies of cell-cell interactions or ultrasonic manipulation of cells. The device has been designed to be easy to use, to allow long-term assays (spanning several days) with read-outs based on high-resolution imaging or high-content screening. This study is focused on screening applications and an automatic cell counting protocol is described and evaluated. Finally, we have tested the device and automatic counting by studying the selective survival and clonal expansion of 721.221 B cells transfected to express HLA Cw6-GFP compared to untransfected 721.221 B cells when grown under antibiotic selection for 3 days. The device and automated analysis protocol make up the foundation for development of several novel cellular imaging assays.
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| 32. |
- Frisk, T., et al.
(författare)
-
Live-cell imaging of natural killer cell mediated tumor rejection in arrays of microwells
- 2010
-
Ingår i: 14th International Conference on Miniaturized Systems for Chemistry and Life Sciences 2010, MicroTAS 2010. - 9781618390622 ; , s. 950-952
-
Konferensbidrag (refereegranskat)abstract
- Due to the inherent heterogeneity of immune cell populations a comprehensive view of immune functions can only be achieved by collecting data from many individual cells. We here demonstrate a novel multi-well microchip platform for cell analysis, which we use to study the interaction between natural killer (NK) cells and their target cells.
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| 33. |
- Gaballa, Ahmed, et al.
(författare)
-
T-cell frequencies of CD8(+) gamma delta and CD27(+) gamma delta cells in the stem cell graft predict the outcome after allogeneic hematopoietic cell transplantation
- 2019
-
Ingår i: Bone Marrow Transplantation. - : NATURE PUBLISHING GROUP. - 0268-3369 .- 1476-5365. ; 54:10, s. 1562-1574
-
Tidskriftsartikel (refereegranskat)abstract
- The impact of intra-graft T cells on the clinical outcome after allogeneic hematopoietic cell transplantation has been investigated. Most previous studies have focused on the role of alpha beta cells while gamma delta cells have received less attention. It has been an open question whether gamma delta cells are beneficial or not for patient outcome, especially with regards to graft versus host disease. In this study, graft composition of.d cell subsets was analyzed and correlated to clinical outcome in 105 recipients who underwent allogeneic hematopoietic cell transplantation between 2013 and 2016. We demonstrate for the first time that grafts containing higher T-cell proportions of CD8(+) gamma delta cells were associated with increased cumulative incidence of acute graft versus host disease grade II-III (50% vs 22.6%; P = 0.008). Additionally, graft T-cell frequency of CD27(+) gamma delta cells was inversely correlated with relapse (P = 0.006) and CMV reactivation (P = 0.05). We conclude that clinical outcome after allogeneic hematopoietic cell transplantation is influenced by the proportions of distinct gamma delta cell subsets in the stem cell graft. We also provide evidence that CD8(+) gamma delta cells are potentially alloreactive and may play a role in acute graft versus host disease. This study illustrates the importance of better understanding of the role of distinct subsets of.d cells in allogeneic hematopoietic cell transplantation.
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| 34. |
- Guldevall, Karolin
(författare)
-
Development of Microchip-based Assays to Study Immune Cell Interactions at the Single Cell Level
- 2011
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Immune cell populations are constantly divided into smaller and smaller subsets defined by newly emerging cellular markers. However, there is a growing awareness of the functional heterogeneities in between cells even within small populations, in addition to the heterogeneity over time. One may ask whether a population is correctly defined only by cellular markers or if the functionality should be regarded as well? Many of today’s techniques only measures at the population level, giving an average estimate of the behavior of that pool of cells, but failing to detect rare possibly important events. Thus, high-throughput experimental approaches to analyze single cells over time are required to address cellular heterogeneity. Progress in the fields of microfabrication, microscopy and computing have paved the way for increasingly efficient tools for studies on the single cell level, and a variety of devices have been described by others. However, few of them are suitable for long-term imaging of dynamic events such as cell-cell interactions or migration. In addition, for efficient recording of many individual events it is desirable to scale down the cells’ interaction volume; not only to shorten the time to interaction, but also to increase the number of individual events in a given area; thereby pushing a screening approach. To address these questions, a complete microwell array system for imaging of immune cell responses with single-cell resolution was designed. The platform consists of a range of silicon-glass microchips with arrays of miniature wells for incubation of cells and a custom made holder that fits conventional microscopes. The device has been designed to allow cells to be kept viable for several days in the wells, to be easy to use and to allow high-resolution imaging. Five different designs were fabricated; all with a specific type of assay in mind, and were evaluated regarding biocompatibility and functionality. One design is aimed towards screening applications, making an automatic cell counting protocol necessary in order to analyze the massive amount of data generated; this program is also described and evaluated. We here show that our silicon microwell platform allows long-term studies (up to several days), with the possibility of both time-lapse and high-resolution imaging of a variety of immune cell behavior. Using time-lapse imaging we confirmed immune cell heterogeneity in NK cell populations regarding both cytotoxicity and migrational behavior. The automatic counting program was tested and showed similar results compared to both manual counting and FACS. In addition, the large numbers of wells that can be simultaneously imaged, provide new statistical information that will lead to a better understanding of the function and regulation of the immune system at the single cell level. Altogether, our technique enables novel types of cellular imaging assays allowing data collection at a level of resolution not previously obtained – this was shown to be important for performing basic cell biological studies, but may also prove valuable in the proposed future medical applications.
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| 35. |
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| 36. |
- Guldevall, Karolin, et al.
(författare)
-
Imaging Immune Surveillance of Individual Natural Killer Cells Confined in Microwell Arrays
- 2010
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 5:11, s. e15453-
-
Tidskriftsartikel (refereegranskat)abstract
- New markers are constantly emerging that identify smaller and smaller subpopulations of immune cells. However, there is a growing awareness that even within very small populations, there is a marked functional heterogeneity and that measurements at the population level only gives an average estimate of the behaviour of that pool of cells. New techniques to analyze single immune cells over time are needed to overcome this limitation. For that purpose, we have designed and evaluated microwell array systems made from two materials, polydimethylsiloxane (PDMS) and silicon, for high-resolution imaging of individual natural killer (NK) cell responses. Both materials were suitable for short-term studies (<4 hours) but only silicon wells allowed long-term studies (several days). Time-lapse imaging of NK cell cytotoxicity in these microwell arrays revealed that roughly 30% of the target cells died much more rapidly than the rest upon NK cell encounter. This unexpected heterogeneity may reflect either separate mechanisms of killing or different killing efficiency by individual NK cells. Furthermore, we show that high-resolution imaging of inhibitory synapse formation, defined by clustering of MHC class I at the interface between NK and target cells, is possible in these microwells. We conclude that live cell imaging of NK-target cell interactions in multi-well microstructures are possible. The technique enables novel types of assays and allow data collection at a level of resolution not previously obtained. Furthermore, due to the large number of wells that can be simultaneously imaged, new statistical information is obtained that will lead to a better understanding of the function and regulation of the immune system at the single cell level.
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| 37. |
- Guldevall, Karolin, et al.
(författare)
-
Microchip screening Platform for single cell assessment of NK cell cytotoxicity
- 2016
-
Ingår i: Frontiers in Immunology. - : FRONTIERS MEDIA SA. - 1664-3224. ; 7
-
Tidskriftsartikel (refereegranskat)abstract
- Here, we report a screening platform for assessment of the cytotoxic potential of individual natural killer (NK) cells within larger populations. Human primary NK cells were distributed across a silicon-glass microchip containing 32,400 individual microwells loaded with target cells. Through fluorescence screening and automated image analysis, the numbers of NK and live or dead target cells in each well could be assessed at different time points after initial mixing. Cytotoxicity was also studied by time-lapse live-cell imaging in microwells quantifying the killing potential of individual NK cells. Although most resting NK cells (approximate to 75%) were non-cytotoxic against the leukemia cell line K562, some NK cells were able to kill several (>= 3) target cells within the 12-h long experiment. In addition, the screening approach was adapted to increase the chance to find and evaluate serial killing NK cells. Even if the cytotoxic potential varied between donors, it was evident that a small fraction of highly cytotoxic NK cells were responsible for a substantial portion of the killing. We demonstrate multiple assays where our platform can be used to enumerate and characterize cytotoxic cells, such as NK or T cells. This approach could find use in clinical applications, e.g., in the selection of donors for stem cell transplantation or generation of highly specific and cytotoxic cells for adoptive immunotherapy.
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| 38. |
- Guldevall, Karolin, 1981-
(författare)
-
Single Cell Investigations of the Functional Heterogeneity Within Immune Cell Populations : a Microchip-based Study
- 2014
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Immune cell populations are constantly divided into smaller and smaller subsets defined by newly emerging cellular markers. However, there is a growing awareness of the functional heterogeneities in between cells even within small populations, in addition to the heterogeneity over time. One may ask whether a population is correctly defined only by cellular markers or if the functionality should be regarded as well? Many of today’s techniques only measure at the population level, giving an average estimate of the behavior of that pool of cells, but failing to detect rare possibly important events. Thus, high-throughput experimental approaches to analyze single cells over time are required to address cellular heterogeneity.Progress in the fields of microfabrication, microscopy and computing have paved the way for increasingly efficient tools for studies on the single cell level, and a variety of devices have been described by others. However, few of them are suitable for long-term imaging of dynamic events such as cell-cell interactions or migration. In addition, for efficient recording of many individual events it is desirable to scale down the cells’ interaction volume; not only to shorten the time to interaction, but also to increase the number of individual events in a given area; thereby pushing a screening approach.To address these questions, a complete microwell array system for imaging of immune cell responses with single-cell resolution was designed. The platform consists of a range of silicon-glass microchips with arrays of miniature wells for incubation of cells and a custom made holder that fits conventional microscopes. The device has been designed to allow cells to be kept viable for several days in the wells, to be easy to use and to allow high-resolution imaging. Five different designs were fabricated; all with a specific type of assay in mind, and were evaluated regarding biocompatibility and functionality. Here, the design aimed for screening applications is the main focus. In this approach a large amount, tens of thousands, of small wells are imaged two to three times: first directly post-seeding of effector and target cells to register the well’s content, and second after some time has passed to allow for cell-cell interactions. The final read-out is the number of killed target cells in each well, making an automatic cell counting protocol necessary in order to analyze the massive amount of data generated.We here show that our silicon microwell platform allows long-term studies with the possibility of both time-lapse and high-resolution imaging of a variety of immune cell behavior. Using both time-lapse imaging and the screening approach we confirmed and investigated immune cell heterogeneity within NK cell populations in regards to both cytotoxicity and migrational behavior. In addition, two different types of cytolytic behavior in NK cells, termed fast and slow killing, were described and evaluated in regards to dynamic parameters; like conjugation and attachment time. We could also quantify the type of cytolytic response in relation to serial killing NK cells, and saw that serial killing NK cells more often induced fast target cell death. Further investigations using the screening approach have shown that serial killing NK cells also differ from other NK cells in their morphology, being both larger and with a more elongated shape. So far the platform has been used to gain better understanding of some aspects of NK cell biology, but there is still much left to explore. With the addition of an automatic counting program, the large numbers of wells that can be simultaneously imaged will provide new statistical information and enable higher throughput.Altogether, our family of techniques enables novel types of cellular imaging assays allowing data collection at a level of resolution not previously obtained – this was shown to be important for performing basic cell biological studies, but may also prove valuable in the proposed future medical applications such as adoptive cell therapy and stem cell transplantation.
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| 39. |
- Hammer, Quirin, et al.
(författare)
-
Combined Genetic Ablation of CD54 and CD58 in CAR Engineered Cytotoxic Lymphocytes Effectively Averts Allogeneic Immune Cell Rejection
- 2022
-
Ingår i: Blood. - : American Society of Hematology. - 0006-4971 .- 1528-0020. ; 140:Supplement 1, s. 1165-1166
-
Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Allogeneic cell therapies hold promise to be cost effective with scaled manufacturing for multi-dosing and on-demand off-the-shelf availability. A critical consideration for allogeneic cell products is their ability to persist, maintain function and avoid rejection by the patient's immune system. Genetic knockout (KO) of beta-2-microglobulin (B2M) leads to complete loss of cell-surface human leukocyte antigen (HLA) class I expression and efficiently abrogates CD8+ T-cell reactivity. However, loss of HLA class I triggers NK cell-mediated missing-self recognition and manipulation of B2M must therefore be combined with other immune-modulating strategies to limit recipient NK cell reactivity.We hypothesized that rejection by the patient's immune system can be diminished in primary CAR T cells, iPSC-derived T (iT) and NK (iNK) cells by reverse-engineering common tumor escape mechanisms. The adhesion molecules CD54 and CD58 are both present at the target cell side of the immune synapse, and loss of either of these molecules have previously been reported to elicit immune escape. Here, we show that the combined deletion of CD54 and CD58 in allogeneic immune effector cells makes them resistant to rejection by recipient immune cells through unidirectional reduced synapse formation (Figure 1A).HLA class I down-regulation by B2M silencing in primary T and NK cells triggered potent cytotoxicity by resting allogeneic NK cells. This response was mostly driven by educated NK cells expressing either NKG2A or killer cell immunoglobulin-like receptors (KIR) binding to HLA-E and HLA-C, respectively. However, over-expression of HLA-E or single HLA-C ligands in a K562 screening model only shut down the specific response of the NK cell subset carrying the cognate inhibitory receptor, resulting in only partial resistance to NK cells at the bulk level. Notably, the introduction of HLA-E was particularly detrimental in donors with expanded NKG2C+ NK cell subsets, due to its stimulatory effect through the activating NKG2C receptor. In contrast, combined deletion of CD54 and CD58 in target cells uniquely decreased the response of all tested NK cell subsets and showed universal reduction across NK cell populations from 18 healthy donors (Figure 1B). To delineate the mechanisms behind the increased resistance of target cells carrying these edits, we studied NK cell-target cell interactions at the single cell level by confocal microscopy in microchips. Allogeneic NK cells formed fewer conjugates and failed to form productive immune synapses with CD54-/-CD58-/- target cells, supporting the notion that they are more resistant to NK-cell mediated killing by unidirectional altered adhesion.We next introduced these edits in primary B2M-/- T cells engineered to express a second generation CAR19 from the TRAC locus. Corroborating the K562 screen, CD54-/-CD58-/-B2M-/- CAR-T cells had a selective survival advantage over B2M-/- CAR T cells and HLA-E-over-expressing B2M-/- CAR T cells in conventional mixed lymphocyte reaction (MLR) assays in vitro. Furthermore, we established an in vivo model to probe the effect of different genetic edits on the persistence of allogeneic cell therapy products. To this end, a mixed population of B2M-/- CAR T cells additionally bearing either CD54 and/or CD58 KO, HLA-E over-expression, or no further edits were infused into mice harboring allogeneic healthy donor PBMC. We found that CD54-/-CD58-/-B2M-/- CAR T cells had significantly better in vivo persistence compared to both B2M-/- CAR T cells and HLA-E+B2M-/- CAR T cells in the presence of PBMC from healthy donors (Figure 1B).Although multiplexed editing is feasible in primary CAR T cells, the iPSC platform has an unmatched capacity for homogenously introducing multiple immune-evasion strategies for off-the-shelf cell therapy. Similar to primary CAR T cells, multiplexed edited CD54-/-CD58-/-B2M-/-CIITA-/- iNK cells showed normal growth kinetics and were resistant to rejection by activated allogeneic NK cells in MLR assays.Together, these data demonstrate that reverse-engineering of common tumor escape mechanisms, which render target cells less susceptible to immune synapse formation, is an effective strategy to avert immune rejection of allogeneic CAR T and iPSC-derived CAR NK cells.
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| 40. |
- Hammer, Quirin, et al.
(författare)
-
Genetic ablation of adhesion ligands averts rejection of allogeneic immune cells
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- A significant barrier to the broad clinical implementation of allogeneic cell therapies is rejection of the allogeneic cells by the recipient immune system. Silencing of β-2-microglobulin (B2M) expression is a commonly employed strategy to evade T cell mediated rejection; however, the absence of B2M triggers missing-self responses by recipient natural killer (NK) cells. Here, we demonstrate that deletion of the adhesionligands CD54 and CD58 on allogeneic cells dampens recipient NK cell reactivityindependent of NK cell sub-population and inhibitory receptor expression. Additionally,genetic ablation of CD54 and CD58 in B2M-deficient allogeneic CAR T cells andinduced pluripotent stem cell-derived NK (iPSC-NK) cells reduces their susceptibility to rejection by recipient NK cells both in vitro and in vivo without affecting their anti-tumor effector potential. Thus, these data show that genetic ablation of adhesion ligands effectively mitigates rejection of allogeneic immune cells, enabling the generation of rejection-resistant allogeneic cell products.
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