Change search
Refine search result
1 - 9 of 9
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1. Forslund, E.
    et al.
    Guldevall, Karolin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Olofsson, Per E.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Frisk, Thomas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Christakou, Athanasia E.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Wiklund, Martin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biomedical and X-ray Physics.
    Önfelt, Björn
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Novel microchip-based tools facilitating live cell imaging and assessment of functional heterogeneity within NK cell populations2012In: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 3, no OCT, p. 300-Article in journal (Refereed)
    Abstract [en]

    Each individual has a heterogeneous pool of NK cells consisting of cells that may be specialized towards specific functional responses such as secretion of cytokines or killing of tumor cells. Many conventional methods are not fit to characterize heterogeneous populations as they measure the average response of all cells. Thus, there is a need for experimental platforms that provide single cell resolution. In addition, there are transient and stochastic variations in functional responses at the single cell level, calling for methods that allow studies of many events over extended periods of time. This paper presents a versatile microchip platform enabling long-term microscopic studies of individual NK cells interacting with target cells. Each microchip contains an array of microwells, optimized for medium or high-resolution time-lapse imaging of single or multiple NK and target cells, or for screening of thousands of isolated NK-target cell interactions. Individual NK cells confined with target cells in small microwells is a suitable setup for high-content screening and rapid assessment of heterogeneity within populations, while microwells of larger dimensions are appropriate for studies of NK cell migration and sequential interactions with multiple target cells. By combining the chip technology with ultrasonic manipulation, NK and target cells can be forced to interact and positioned with high spatial accuracy within individual microwells.This setup effectively and synchronously creates NK-target conjugates at hundreds of parallel positions in the microchip. Thus, this facilitates assessment of temporal aspects of NK-target cell interactions, e.g., conjugation, immune synapse formation, and cytotoxic events.The microchip platform presented here can be used to effectively address questions related to fundamental functions of NK cells that can lead to better understanding of how the behavior of individual cells add up to give a functional response at the population level.

  • 2. Forslund, Elin
    et al.
    Sohlberg, Ebba
    Enqvist, Monika
    Olofsson, Per E.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Malmberg, Karl-Johan
    Önfelt, Björn
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab. Karolinska Inst, Sci Life Lab, Dept Microbiol Tumor & Cell Biol, S-17165 Stockholm, Sweden.
    Microchip-Based Single-Cell Imaging Reveals That CD56(dim) CD57(-)KIR(-)NKG2A(+) NK Cells Have More Dynamic Migration Associated with Increased Target Cell Conjugation and Probability of Killing Compared to CD56(dim)CD57(-)KIR(-)NKG2A(-) NK Cells2015In: Journal of Immunology, ISSN 0022-1767, E-ISSN 1550-6606, Vol. 195, no 7, p. 3374-3381Article in journal (Refereed)
    Abstract [en]

    NK cells are functionally educated by self-MHC specific receptors, including the inhibitory killer cell Ig-like receptors (KIRs) and the lectin-like CD94/NKG2A heterodimer. Little is known about how NK cell education influences qualitative aspects of cytotoxicity such as migration behavior and efficacy of activation and killing at the single-cell level. In this study, we have compared the behavior of FACS-sorted CD56(dim)CD57(-)KIR(-)NKG2A(+) (NKG2A(+)) and CD56(dim)CD57(-)KIR(-)NKG2A(+) (lacking inhibitory receptors; IR-) human NK cells by quantifying migration, cytotoxicity, and contact dynamics using microchip-based live cell imaging. NKG2A(+) NK cells displayed a more dynamic migration behavior and made more contacts with target cells than IR-NK cells. NKG2A(+) NK cells also more frequently killed the target cells once a conjugate had been formed. NK cells with serial killing capacity were primarily found among NKG2A(+) NK cells. Conjugates involving IR- NK cells were generally more short-lived and IR- NK cells did not become activated to the same extent as NKG2A(+) NK cells when in contact with target cells, as evident by their reduced spreading response. In contrast, NKG2A(+) and IR- NK cells showed similar dynamics in terms of duration of conjugation periods and NK cell spreading response in conjugates that led to killing. Taken together, these observations suggest that the high killing capacity of NKG2A(+) NK cells is linked to processes regulating events in the recognition phase of NK-target cell contact rather than events after cytotoxicity has been triggered.

  • 3.
    Guldevall, Karolin
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Brandt, Ludwig
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Forslund, Elin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab. Karolinska Inst, Dept Microbiol Tumor & Cell Biol, Sweden.
    Olofsson, Karl
    Frisk, Thomas W.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Olofsson, Per E.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Gustafsson, Karin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Manneberg, Otto
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Vanherberghen, Bruno
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Brismar, Hjalmar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Karre, Klas
    Uhlin, Michael
    Önfelt, Björn
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Microchip screening Platform for single cell assessment of NK cell cytotoxicity2016In: Frontiers in Immunology, ISSN 1664-3224, E-ISSN 1664-3224, Vol. 7, article id 119Article in journal (Refereed)
    Abstract [en]

    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.

  • 4.
    Guldevall, Karolin
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Gustafsson, Karin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Forslund, Elin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Frisk, Thomas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Manneberg, Otto
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Olofsson, Per E.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Tauriainen, Johanna
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Stikvoort, Arwen
    Karolinska Institute.
    Vanherberghen, Bruno
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Brismar, Hjalmar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Mattsson, Jonas
    Karolinska Institute.
    Kärre, Klas
    Karolinska Institute.
    Uhlin, Michael
    Karolinska Institute.
    Önfelt, Bjorn
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Microchip screening platform for assessment of cytotoxic effector cellsManuscript (preprint) (Other academic)
    Abstract [en]

    Here we report a screening platform for assessment of the cytotoxic potential of individual natural killer (NK) or T cells within larger populations. Human primary NK cells or human Epstein-Barr virus (EBV)- specific T 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 effector 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 (≈75%) were non-cytotoxic to the leukemia cell line K562, some NK cells were able to kill several (≥3) target cells within the 12 hours long experiment. We demonstrate that this assay can be used to enumerate and characterize cytotoxic cells, something that could find clinical applications, e.g. in the selection of donors for stem cell transplantation or generation of highly specific and cytotoxic cells for adoptive immunotherapy.

  • 5.
    Olofsson, Per
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Quantitative approaches to studying NK cell functional heterogeneity2014Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    It is commonly stated that the cell is the smallest functional unit of life. By analogy, then, the immune cell is the smallest functional unit of the immune system. Natural killer (NK) cells are effector cells of the innate immune system that are responsible for mediating cellular cytotoxicity against virally infected or neoplastically transformed cells. Many phenotypically distinct subpopulations of NK cells have been discovered, usually by dividing cells on the basis of cell-surface markers. These subpopulations are typically described as related to activation or developmental status of the cells. However, how these distinct phenotypes correlate with behavior in e.g. NK–target interactions is less widely understood. There is therefore a need to study NK cell behavior down at the single-cell level. The aim of this thesis is to approach methods that quantitatively describe these single-cell-level behavioral differences of NK cells.

    Using a newly developed single-cell imaging and screening assay, we trap small populations of NK and target cells inside microwells, where they can be imaged over extended periods of time. We have performed experiments on both resting and IL-2-activated NK cells and quantified their cytotoxic behavior. One major discovery was that a small population of NK cells mediate a majority of the cytotoxicity directed against target cells. A particularly cytotoxic group of cells, which we termed “serial killers”, displayed faster and more effective cytotoxicity.

    Also, we identified differences between resting and activated NK cells in regard to their migration and contact dynamics. Activated NK cells were found to more readily adhere to targets cells than did NK cells freshly isolated from peripheral blood. Apart form migration and contact dynamics, we have also quantified killing behavior, where NK cells can be seen to exhibit a behavior we term multiple lytic hits on the basis of analyzing target cell fluorescence profiles.

    We have quantified these heterogeneities and developed tools that can be used to further study and elucidate differences in the behavior of single immune cells. These methods, and automated single-cell analysis methods, will likely play a more important role in the study of immune responses in the future.

     

  • 6.
    Olofsson, Per E.
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biophysics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Brandt, Ludwig
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biophysics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Magnusson, Klas E. G.
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre.
    Frisk, Thomas
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biophysics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Jaldén, Joakim
    KTH, School of Electrical Engineering (EES), Signal Processing. KTH, School of Electrical Engineering and Computer Science (EECS), Centres, ACCESS Linnaeus Centre.
    Önfelt, Björn
    KTH, School of Engineering Sciences (SCI), Applied Physics, Biophysics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    A collagen-based microwell migration assay to study NK-target cell interactions2019In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 9, article id 10672Article in journal (Refereed)
    Abstract [en]

    Natural killer (NK) cell cytotoxicity in tissue is dependent on the ability of NK cells to migrate through the extracellular matrix (ECM) microenvironment. Traditional imaging studies of NK cell migration and cytotoxicity have utilized 2D surfaces, which do not properly reproduce the structural and mechanical cues that shape the migratory response of NK cells in vivo. Here, we have combined a microwell assay that allows long-term imaging and tracking of small, well-defined populations of NK cells with an interstitial ECM-like matrix. The assay allows for long-term imaging of NK-target cell interactions within a confined 3D volume. We found marked differences in motility between individual cells with a small fraction of the cells moving slowly and being confined to a small volume within the matrix, while other cells moved more freely. A majority of NK cells also exhibited transient variation in their motility, alternating between periods of migration arrest and movement. The assay could be used as a complement to in vivo imaging to study human NK cell heterogeneity in migration and cytotoxicity.

  • 7.
    Olofsson, Per E
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Forslund, Elin
    Vanherberghen, Bruno
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Chechet, Ksenia
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Mickelin, Oscar
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Rivera Ahlin, Alexander
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Everhorn, Tobias
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Önfelt, Björn
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics.
    Distinct Migration and Contact Dynamics of Resting and IL-2-Activated Human Natural Killer Cells.2014In: Frontiers in immunology, ISSN 1664-3224, Vol. 5, p. 80-Article in journal (Refereed)
    Abstract [en]

    Natural killer (NK) cells serve as one of the first lines of defense against viral infections and transformed cells. NK cell cytotoxicity is not dependent on antigen presentation by target cells, but is dependent on integration of activating and inhibitory signals triggered by receptor-ligand interactions formed at a tight intercellular contact between the NK and target cell, i.e., the immune synapse. We have studied the single-cell migration behavior and target-cell contact dynamics of resting and interleukin (IL)-2-activated human peripheral blood NK cells. Small populations of NK cells and target cells were confined in microwells and imaged by fluorescence microscopy for >8 h. Only the IL-2-activated population of NK cells showed efficient cytotoxicity against the human embryonic kidney 293T target cells. We found that although the average migration speeds were comparable, activated NK cells showed significantly more dynamic migration behavior, with more frequent transitions between periods of low and high motility. Resting NK cells formed fewer and weaker contacts with target cells, which manifested as shorter conjugation times and in many cases a complete lack of post-conjugation attachment to target cells. Activated NK cells were approximately twice as big as the resting cells, displayed a more migratory phenotype, and were more likely to employ "motile scanning" of the target-cell surface during conjugation. Taken together, our experiments quantify, at the single-cell level, how activation by IL-2 leads to altered NK cell cytotoxicity, migration behavior, and contact dynamics.

  • 8.
    Vanherberghen, Bruno
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Olofsson, Per E.
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Forslund, Elin
    Sternberg-Simon, Michal
    Khorshidi, Mohammad Ali
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Pacouret, Simon
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Guldevall, Karolin
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Enqvist, Monika
    Malmberg, Karl-Johan
    Mehr, Ramit
    Önfelt, Bjorn
    KTH, School of Engineering Sciences (SCI), Applied Physics, Cell Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Classification of human natural killer cells based on migration behavior and cytotoxic response2013In: Blood, ISSN 0006-4971, E-ISSN 1528-0020, Vol. 121, no 8, p. 1326-1334Article in journal (Refereed)
    Abstract [en]

    Despite intense scrutiny of the molecular interactions between natural killer (NK) and target cells, few studies have been devoted to dissection of the basic functional heterogeneity in individual NK cell behavior. Using a microchip-based, time-lapse imaging approach allowing the entire contact history of each NK cell to be recorded, in the present study, we were able to quantify how the cytotoxic response varied between individual NK cells. Strikingly, approximately half of the NK cells did not kill any target cells at all, whereas a minority of NK cells was responsible for a majority of the target cell deaths. These dynamic cytotoxicity data allowed categorization of NK cells into 5 distinct classes. A small but particularly active subclass of NK cells killed several target cells in a consecutive fashion. These "serial killers" delivered their lytic hits faster and induced faster target cell death than other NK cells. Fast, necrotic target cell death was correlated with the amount of perforin released by the NK cells. Our data are consistent with a model in which a small fraction of NK cells drives tumor elimination and inflammation.

  • 9.
    Verron, Quentin
    et al.
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences (SCI), Applied Physics.
    Guldevall, Karolin
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Brandt, Ludwig
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences (SCI), Applied Physics.
    Olofsson, Per E.
    KTH, Centres, Science for Life Laboratory, SciLifeLab. KTH, School of Engineering Sciences (SCI), Applied Physics.
    Frisk, Thomas
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab.
    Önfelt, Björn
    KTH, School of Engineering Sciences (SCI), Applied Physics. KTH, Centres, Science for Life Laboratory, SciLifeLab. Karolinska Inst, Dept Microbiol Tumor & Cell Biol, Stockholm, Sweden.
    Microchip screening for single cell assessment and isolation of serial killing NK cells2017In: Scandinavian Journal of Immunology, ISSN 0300-9475, E-ISSN 1365-3083, Vol. 86, no 4, p. 347-347Article in journal (Other academic)
1 - 9 of 9
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf