CD4 and CD8 mark helper and cytotoxic T cell lineages, respectively, and serve as coreceptors for MHC-restricted TCR recognition. How coreceptor expression is matched with TCR specificity is central to understanding CD4/CD8 lineage choice, but visualising coreceptor gene activity in individual selection intermediates has been technically challenging. It therefore remains unclear whether the sequence of coreceptor gene expression in selection intermediates follows a stereotypic pattern, or is responsive to signaling. Here we use single cell RNA sequencing (scRNA-seq) to classify mouse thymocyte selection intermediates by coreceptor gene expression. In the unperturbed thymus, Cd4+Cd8a- selection intermediates appear before Cd4-Cd8a+ selection intermediates, but the timing of these subsets is flexible according to the strength of TCR signals. Our data show that selection intermediates discriminate MHC class prior to the loss of coreceptor expression and suggest a model where signal strength informs the timing of coreceptor gene activity and ultimately CD4/CD8 lineage choice.
- MeSH
- aktivace lymfocytů genetika MeSH
- analýza hlavních komponent MeSH
- buněčná diferenciace imunologie MeSH
- buněčný rodokmen imunologie MeSH
- CD4-pozitivní T-lymfocyty cytologie imunologie MeSH
- CD8-pozitivní T-lymfocyty cytologie imunologie MeSH
- cytokiny metabolismus MeSH
- DNA vazebné proteiny metabolismus MeSH
- histokompatibilita - antigeny metabolismus MeSH
- messenger RNA genetika metabolismus MeSH
- myši inbrední C57BL MeSH
- protein PEBP2A3 metabolismus MeSH
- receptory antigenů T-buněk metabolismus MeSH
- regulace genové exprese MeSH
- signální transdukce MeSH
- thymus cytologie imunologie MeSH
- transkripční faktory metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Overtly self-reactive T cells are removed during thymic selection. However, it has been recently established that T cell self-reactivity promotes protective immune responses. Apparently, the level of self-reactivity of mature T cells must be tightly balanced. Our mathematical model and experimental data show that the dynamic regulation of CD4- and CD8-LCK coupling establish the self-reactivity of the peripheral T cell pool. The stoichiometry of the interaction between CD8 and LCK, but not between CD4 and LCK, substantially increases upon T cell maturation. As a result, peripheral CD8+ T cells are more self-reactive than CD4+ T cells. The different levels of self-reactivity of mature CD8+ and CD4+ T cells likely reflect the unique roles of these subsets in immunity. These results indicate that the evolutionary selection pressure tuned the CD4-LCK and CD8-LCK stoichiometries, as they represent the unique parts of the proximal T cell receptor (TCR) signaling pathway, which differ between CD4+ and CD8+ T cells.
- MeSH
- antigeny metabolismus MeSH
- buněčná diferenciace MeSH
- CD4-pozitivní T-lymfocyty cytologie metabolismus MeSH
- CD8-pozitivní T-lymfocyty cytologie metabolismus MeSH
- homeostáza MeSH
- myši inbrední C57BL MeSH
- signální transdukce MeSH
- tyrosinkinasa p56(lck), specifická pro lymfocyty metabolismus MeSH
- vazba proteinů MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
The interaction of T-cell receptors (TCRs) with self- and non-self-peptides in the major histocompatibility complex (MHC) stimulates crucial signaling events, which in turn can activate T lymphocytes. A variety of accessory molecules further modulate T-cell signaling. Of these, the CD4 and CD8 coreceptors make the most critical contributions to T cell sensitivity in vivo. Whereas, CD4 function in T cell development is well-characterized, its role in peripheral T cells remains incompletely understood. It was originally suggested that CD4 stabilizes weak interactions between TCRs and peptides in the MHC and delivers Lck kinases to that complex. The results of numerous experiments support the latter role, indicating that the CD4-Lck complex accelerates TCR-triggered signaling and controls the availability of the kinase for TCR in the absence of the ligand. On the other hand, extremely low affinity of CD4 for MHC rules out its ability to stabilize the receptor-ligand complex. In this review, we summarize the current knowledge on CD4 in T cells, with a special emphasis on the spatio-temporal organization of early signaling events and the relevance for CD4 function. We further highlight the capacity of CD4 to interact with the MHC in the absence of TCR. It drives the adhesion of T cells to the cells that express the MHC. This process is facilitated by the CD4 accumulation in the tips of microvilli on the surface of unstimulated T cells. Based on these observations, we suggest an alternative model of CD4 role in T-cell activation.
- MeSH
- aktivace lymfocytů * MeSH
- CD4-pozitivní T-lymfocyty cytologie imunologie MeSH
- CD8-pozitivní T-lymfocyty cytologie metabolismus MeSH
- histokompatibilita - antigeny imunologie MeSH
- lidé MeSH
- receptory antigenů T-buněk imunologie MeSH
- signální transdukce imunologie MeSH
- tyrosinkinasa p56(lck), specifická pro lymfocyty imunologie MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
The fetus is thought to be protected from exposure to foreign antigens, yet CD45RO+ T cells reside in the fetal intestine. Here we combined functional assays with mass cytometry, single-cell RNA sequencing and high-throughput T cell antigen receptor (TCR) sequencing to characterize the CD4+ T cell compartment in the human fetal intestine. We identified 22 CD4+ T cell clusters, including naive-like, regulatory-like and memory-like subpopulations, which were confirmed and further characterized at the transcriptional level. Memory-like CD4+ T cells had high expression of Ki-67, indicative of cell division, and CD5, a surrogate marker of TCR avidity, and produced the cytokines IFN-γ and IL-2. Pathway analysis revealed a differentiation trajectory associated with cellular activation and proinflammatory effector functions, and TCR repertoire analysis indicated clonal expansions, distinct repertoire characteristics and interconnections between subpopulations of memory-like CD4+ T cells. Imaging mass cytometry indicated that memory-like CD4+ T cells colocalized with antigen-presenting cells. Collectively, these results provide evidence for the generation of memory-like CD4+ T cells in the human fetal intestine that is consistent with exposure to foreign antigens.
- MeSH
- antigen Ki-67 genetika imunologie metabolismus MeSH
- antigen prezentující buňky cytologie imunologie metabolismus MeSH
- antigeny CD5 genetika imunologie metabolismus MeSH
- CD4-pozitivní T-lymfocyty cytologie imunologie metabolismus MeSH
- imunofenotypizace MeSH
- imunologická paměť genetika imunologie MeSH
- kultivované buňky MeSH
- lidé MeSH
- plod cytologie imunologie metabolismus MeSH
- průtoková cytometrie MeSH
- stanovení celkové genové exprese metody MeSH
- střeva cytologie embryologie imunologie MeSH
- vysoce účinné nukleotidové sekvenování MeSH
- vývojová regulace genové exprese imunologie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Hashimoto's thyroiditis (HT) is an organ-specific autoimmune disorder characterized by progressive thyroid failure. Th1 and Treg subset of CD4(+) cells have been implicated in the pathogenesis; however, less is known about their respective roles across the spectrum of HT clinical presentations. To shed more light on CD4(+) subsets role in HT, we investigated the mRNA expression levels of several Th1/Treg-associated transcription factors (T-bet/ETS1, HIF1α/BLIMP1/FOXP3) in peripheral blood T cells of 10 hypothyroid, untreated HT patients, 10 hypothyroid patients undergoing hormone replacement therapy, 12 euthyroid HT subjects, and 11 healthy controls by the qRT-PCR. Compared to euthyroid HT patients and controls, both hypothyroid (2.34-fold difference versus controls, P < 0.01) and thyroxine-supplemented patients (2.5-fold, P < 0.001) showed an increased FOXP3 mRNA expression in T cells. Similarly, mRNA expression levels of T-bet were upregulated in severely affected but not in euthyroid HT subjects (2.37-fold and 3.2-fold, hypothyroid and thyroxine-supplemented HT patients versus controls, resp., P < 0.01). By contrast, no differences in mRNA expression levels of ETS1, BLIMP1, and HIF1α were observed across the study groups. In summary, severe but not euthyroid HT was associated with robust upregulation of T-bet and FOXP3 mRNA in peripheral T cells, independent of the thyroid hormone status but proportional to disease activity.
- MeSH
- autoimunitní nemoci metabolismus MeSH
- CD4-pozitivní T-lymfocyty cytologie metabolismus MeSH
- dospělí MeSH
- forkhead transkripční faktory metabolismus MeSH
- Hashimotova nemoc imunologie metabolismus MeSH
- hormony terapeutické užití MeSH
- hypotyreóza imunologie metabolismus MeSH
- kohortové studie MeSH
- leukocyty mononukleární cytologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- messenger RNA metabolismus MeSH
- proteiny T-boxu metabolismus MeSH
- regulace genové exprese MeSH
- studie případů a kontrol MeSH
- upregulace MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- biologické markery analýza MeSH
- CD4-pozitivní T-lymfocyty cytologie MeSH
- HIV infekce diagnóza MeSH
- klinické laboratorní techniky ekonomika přístrojové vybavení využití MeSH
- lidé MeSH
- průtoková cytometrie * metody přístrojové vybavení využití MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- novinové články MeSH
- Geografické názvy
- Afrika MeSH
- O autorovi
- Göhde, Wolfgang Autorita
In order to design a new Salmonella enterica vaccine, one needs to understand how naive and immune chickens interact differently when exposed to S. enterica. In this study we therefore determined the immune response of vaccinated and non-vaccinated chickens after intravenous infection with Salmonella enterica serovar Enteritidis (S. Enteritidis). Using flow cytometry we showed that 4 days post infection (DPI), counts of CD4 and B-lymphocytes did not change, CD8 and γδ T-lymphocytes decreased and macrophages and heterophils increased in the spleen. When vaccinated and non-vaccinated chickens were compared, only macrophages and heterophils were found in significantly higher counts in the spleens of the non-vaccinated chickens. The non-vaccinated chickens also expressed higher anti-LPS antibodies than the vaccinated chickens. The expression of interleukin (IL)1β, IL6, IL8, IL18, LITAF, IFNγ and iNOS did not exhibit any clear pattern in the cells sorted from the spleens of vaccinated or non-vaccinated chickens. Only IL17 and IL22 showed a differential expression in the CD4 T-lymphocytes of the vaccinated and non-vaccinated chickens at 4 DPI, both being expressed at a higher level in the non-vaccinated chickens. Due to a similar IFNγ expression in the CD4 T-lymphocytes in both the vaccinated and non-vaccinated chickens, and a variable IL17 expression oscillating around IFNγ expression levels, the IL17∶IFNγ ratio in CD4 T-lymphocytes was found to be central for the outcome of the immune response. When IL17 was expressed at higher levels than IFNγ in the non-vaccinated chickens, the Th17 immune response with a higher macrophage and heterophil infiltration in the spleen dominated. However, when the expression of IL17 was lower than that of IFNγ as in the vaccinated chickens, the Th1 response with a higher resistance to S. Enteritidis infection dominated.
- MeSH
- CD4-pozitivní T-lymfocyty cytologie MeSH
- cytokiny metabolismus MeSH
- ELISA metody MeSH
- interferon gama metabolismus MeSH
- interleukin-17 metabolismus MeSH
- kur domácí MeSH
- leukocyty cytologie MeSH
- lipopolysacharidy metabolismus MeSH
- makrofágy metabolismus MeSH
- nemoci drůbeže imunologie prevence a kontrola MeSH
- polymerázová řetězová reakce metody MeSH
- průtoková cytometrie metody MeSH
- Salmonella enteritidis metabolismus MeSH
- salmonelové vakcíny metabolismus MeSH
- salmonelóza imunologie prevence a kontrola MeSH
- slezina cytologie MeSH
- Th1 buňky cytologie MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- aktivace viru * imunologie účinky léků MeSH
- CD4-pozitivní T-lymfocyty cytologie imunologie účinky léků MeSH
- HIV infekce * farmakoterapie imunologie patofyziologie virologie MeSH
- HIV-1 * fyziologie imunologie patogenita účinky léků MeSH
- kyseliny hydroxamové aplikace a dávkování farmakologie MeSH
- latence viru imunologie účinky léků MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
Řada pozorování nasvědčuje tomu, že u nemocných s renálním karcinomem (renal cell carcinoma ? RCC) hraje imunitní systém důležitou roli při kontrole růstu nádoru. RCC je více než jiné nádory infiltrován leukocyty (Tumor Infiltrating Lymphocytes ? TIL). Dominantní populaci TIL buněk tvoří T-lymfocyty. Názory na úlohu T-lymfocytárních subpopulací, B-lymfocytů a NK buněk v protinádorové odezvě nejsou jednotné. Cíl: Stanovit fenotyp a aktivaci lymfocytárních buněk a porovnat jejich zastoupení v nádorovém stromatu (TIL), v periferní krvi a v krvi z renální žíly u nemocných s RCC. Soubor nemocných a metodika: Vzorky periferní krve z kubitální a renální žíly a buňky nádorového stromatu byly získány od 60 pacientů v průběhu operace pro primární RCC. TIL byly izolovány z mechanicky dezintegrované nádorové tkáně. PBL a TIL byly podrobeny imunofenotypové multiparametrové analýze. Pomocí průtokového cytometru byly charakterizovány jejich povrchové a aktivační znaky. Výsledky: Hlavní populací TIL byly T-lymfocyty CD3+ (70,4 %). Počet CD3+/CD8+ T-lymfocytů byl signifikantně vyšší v TIL, 39,7 % (p < 0,01), zatímco CD4+ T-lymfocyty byly většinovou populací v periferní krvi, 41,35 % (p < 0,001). Zastoupení CD3+/69+ T-lymfocytů bylo signifikantně vyšší v TIL (32,05 %) než v PBL (p < 0,001). Naopak, počty CD3+/CD25+, CD8+/57+ a CD4+/RA+ (naivní CD4+ T-lymfocyty) byly vyšší v PBL (p < 0,001). Rozdíly v zastoupení NK buněk (CD3?/16+56+) a CD3+/DR+ T buněk v TIL a PBL nebyly signifikantní. Závěr: Uvedené výsledky dokazují, že v porovnávaných kompartmentech (tumor/PBL) jsou charakteristiky a intenzita protinádorové odezvy rozdílné. CD3+/CD8+ T-lymfocyty jsou dominantní lymfocytární populací TIL. Znalost fenotypu a funkcí efektorových buněk zodpovědných za protinádorovou odpověď jsou základní podmínkou pochopení protinádorové imunitní odpovědi a jejího selhání.
