title: Primary human CD4+ T cells have diverse levels of membrane lipid order that correlate with their function.
abstract: Membrane lipid microdomains (lipid rafts) play an important role in T cell function by forming areas of high lipid order that facilitate activation. However, their role in regulating T cell differentiation and function remains controversial. In this study, by applying a new approach involving microscopy and flow cytometry, we characterize membrane lipid order in ex vivo primary human CD4(+) T cells. We reveal that differential membrane lipid order dictates the response to TCR stimulation. T cells with high membrane order formed stable immune synapses and proliferated robustly, intermediate order cells had reduced proliferative ability accompanied by unstable immune synapse formation, whereas low order T cells were profoundly unresponsive to TCR activation. We also observed that T cells from patients with autoimmune rheumatic disease had expanded intermediate order populations compared with healthy volunteers. This may be important in dictating the nature of the immune response since most IFN-γ(+)CD4(+) T cells were confined within intermediate membrane order populations, whereas IL-4(+)CD4(+) T cells were contained within the high order populations. Importantly, we were able to alter T cell function by pharmacologically manipulating membrane order. Thus, the results presented from this study identify that ex vivo CD4(+) T cells sustain a gradient of plasma membrane lipid order that influences their function in terms of proliferation and cytokine production. This could represent a new mechanism to control T cell functional plasticity, raising the possibility that therapeutic targeting of membrane lipid order could direct altered immune cell activation in pathology.
authors.affiliation: Division of Medicine, Centre for Rheumatology Research, University College London, London W1P 4JF, United Kingdom.
authors.forename: Laura
authors.initials: L
authors.lastname: Miguel
authors.forename: Dylan M
authors.initials: DM
authors.lastname: Owen
authors.forename: Chrissie
authors.initials: C
authors.lastname: Lim
authors.forename: Christian
authors.initials: C
authors.lastname: Liebig
authors.forename: Jamie
authors.initials: J
authors.lastname: Evans
authors.forename: Anthony I
authors.initials: AI
authors.lastname: Magee
authors.forename: Elizabeth C
authors.initials: EC
authors.lastname: Jury
mesh_terms: D000328:Adult; D015496:CD4-Positive T-Lymphocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism*; D002478:Cells, Cultured; D018920:Coculture Techniques; D005260:Female; D006801:Humans; D054992:Immunological Synapses / Q000276:immunology; D008213:Lymphocyte Activation / Q000276:immunology; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism* / Q000502:physiology; D021962:Membrane Microdomains / Q000378:metabolism* / Q000502:physiology; D015335:Molecular Probes; D011726:Pyridinium Compounds; D018417:Th1 Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D018418:Th2 Cells / Q000166:cytology / Q000276:immunology / Q000378:metabolism
chemical_list: D008563:Membrane Lipids; D015335:Molecular Probes; D011726:Pyridinium Compounds; C541550:di-4-ANEPPDHQ