Dendritic cells (DC) serve a key function in host defense, linking innate detection of microbes to the activation of pathogen-specific adaptive immune responses. Whether there is cell-intrinsic recognition of HIV-1 by host innate pattern-recognition receptors and subsequent coupling to antiviral T cell responses is not yet known. DC are largely resistant to infection with HIV-1, but facilitate infection of co-cultured T-helper cells through a process of trans-enhancement. We show here that, when DC resistance to infection is circumvented, HIV-1 induces DC maturation, an antiviral type I interferon response and activation of T cells. This innate response is dependent on the interaction of newly-synthesized HIV-1 capsid (CA) with cellular cyclophilin A (CypA) and the subsequent activation of the transcription factor IRF3. Because the peptidyl-prolyl isomerase CypA also interacts with CA to promote HIV-1 infectivity, our results suggest that CA conformation has evolved under opposing selective pressures for infectivity versus furtiveness. Thus, a cell intrinsic sensor for HIV-1 exists in DC and mediates an antiviral immune response, but it is not typically engaged due to absence of DC infection. The virulence of HIV-1 may be related to evasion of this response, whose manipulation may be necessary to generate an effective HIV-1 vaccine.
A cryptic sensor for HIV-1 activates antiviral innate immunity in dendritic cells.
Specimen part
View SamplesT follicular helper (TFH) cells promote affinity maturation of B cells in germinal centers (GCs), whereas T follicular regulatory (TFR) cells limit GC reaction. Store-operated Ca2+ entry (SOCE) through Ca2+ release-activated Ca2+ (CRAC) channels mediated by STIM and ORAI proteins is a fundamental signaling pathway in T lymphocytes. Here we show that SOCE is required for the differentiation and function of both TFH and TFR cells. Conditional deletion of Stim1 and Stim2 genes in T cells or Treg cells results in spontaneous autoantibody production and humoral autoimmunity. Conversely, antibody-mediated immune responses following viral infection critically depend on SOCE in TFH cells. Mechanistically, STIM1 and STIM2 control early TFR and TFH cell differentiation through NFAT-mediated IRF4, BATF and Bcl-6 expression. SOCE plays a dual role in GC response by controlling TFH and TFR cell function, thus enabling protective B cell responses and preventing humoral autoimmunity. Overall design: RNAseq analyses of WT and Stim1Stim2 DKO follicular T cells and non-follicular T cells; 4-6 mice per cohort in duplicates. Mice were infected for 10 days with LCMV.
Store-Operated Ca(2+) Entry in Follicular T Cells Controls Humoral Immune Responses and Autoimmunity.
Specimen part, Subject
View SamplesThe aim of this study was to identify differentially-expressed genes in CCR4hi/CXCR3- and CCR4lo CXCR3+ CCR6+ human Th17 cell subsets
Pro-inflammatory human Th17 cells selectively express P-glycoprotein and are refractory to glucocorticoids.
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View SamplesThe aim of this study was to characterize the transcriptional signature of MDR1+ human memory T cells isolated from clinically inflamed gut tissue, and compare it to local MDR1- memory T cells
Pro-inflammatory human Th17 cells selectively express P-glycoprotein and are refractory to glucocorticoids.
Specimen part
View SamplesInfluence of STIM1 on the transcriptome of CD4+ T cell subsets
STIM1 controls T cell-mediated immune regulation and inflammation in chronic infection.
Treatment
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