RESUMEN
Mechanisms for human memory T cell differentiation and maintenance have largely been inferred from studies of peripheral blood, though the majority of T cells are found in lymphoid and mucosal sites. We present here a multidimensional, quantitative analysis of human T cell compartmentalization and maintenance over six decades of life in blood, lymphoid, and mucosal tissues obtained from 56 individual organ donors. Our results reveal that the distribution and tissue residence of naive, central, and effector memory, and terminal effector subsets is contingent on both their differentiation state and tissue localization. Moreover, T cell homeostasis driven by cytokine or TCR-mediated signals is different in CD4+ or CD8+ T cell lineages, varies with their differentiation stage and tissue localization, and cannot be inferred from blood. Our data provide an unprecedented spatial and temporal map of human T cell compartmentalization and maintenance, supporting distinct pathways for human T cell fate determination and homeostasis.
Asunto(s)
Envejecimiento/inmunología , Linfocitos T/citología , Linfocitos T/inmunología , Adolescente , Adulto , Anciano , Antígenos CD28/metabolismo , Diferenciación Celular , Niño , Preescolar , Humanos , Subunidad alfa del Receptor de Interleucina-7/metabolismo , Tejido Linfoide/citología , Tejido Linfoide/inmunología , Persona de Mediana Edad , Membrana Mucosa/citología , Membrana Mucosa/inmunología , Receptores de Antígenos de Linfocitos T/química , Subgrupos de Linfocitos T/citología , Subgrupos de Linfocitos T/inmunología , Subgrupos de Linfocitos T/metabolismo , Linfocitos T/metabolismo , Donantes de Tejidos , Adulto JovenRESUMEN
Innate lymphoid cells (ILC) play critical roles in regulating immunity, inflammation, and tissue homeostasis in mice. However, limited access to non-diseased human tissues has hindered efforts to profile anatomically-distinct ILCs in humans. Through flow cytometric and transcriptional analyses of lymphoid, mucosal, and metabolic tissues from previously healthy human organ donors, here we have provided a map of human ILC heterogeneity across multiple anatomical sites. In contrast to mice, human ILCs are less strictly compartmentalized and tissue localization selectively impacts ILC distribution in a subset-dependent manner. Tissue-specific distinctions are particularly apparent for ILC1 populations, whose distribution was markedly altered in obesity or aging. Furthermore, the degree of ILC1 population heterogeneity differed substantially in lymphoid versus mucosal sites. Together, these analyses comprise a comprehensive characterization of the spatial and temporal dynamics regulating the anatomical distribution, subset heterogeneity, and functional potential of ILCs in non-diseased human tissues.
Asunto(s)
Inmunidad Innata/inmunología , Linfocitos/inmunología , Especificidad de Órganos/inmunología , Transcriptoma/inmunología , Adolescente , Adulto , Anciano , Envejecimiento/genética , Animales , Niño , Preescolar , Femenino , Heterogeneidad Genética , Humanos , Inmunidad Innata/genética , Lactante , Recién Nacido , Linfocitos/metabolismo , Masculino , Ratones , Persona de Mediana Edad , Especificidad de Órganos/genética , Transcriptoma/genética , Adulto JovenRESUMEN
Maturation and migration to lymph nodes (LNs) constitutes a central paradigm in conventional dendritic cell (cDC) biology but remains poorly defined in humans. Using our organ donor tissue resource, we analyzed cDC subset distribution, maturation, and migration in mucosal tissues (lungs, intestines), associated lymph nodes (LNs), and other lymphoid sites from 78 individuals ranging from less than 1 year to 93 years of age. The distribution of cDC1 (CD141hiCD13hi) and cDC2 (Sirp-α+CD1c+) subsets was a function of tissue site and was conserved between donors. We identified cDC2 as the major mature (HLA-DRhi) subset in LNs with the highest frequency in lung-draining LNs. Mature cDC2 in mucosal-draining LNs expressed tissue-specific markers derived from the paired mucosal site, reflecting their tissue-migratory origin. These distribution and maturation patterns were largely maintained throughout life, with site-specific variations. Our findings provide evidence for localized DC tissue surveillance and reveal a lifelong division of labor between DC subsets, with cDC2 functioning as guardians of the mucosa.
Asunto(s)
Células Dendríticas/citología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Citometría de Flujo , Técnica del Anticuerpo Fluorescente , Humanos , Lactante , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Knowledge of human T cells derives chiefly from studies of peripheral blood, whereas their distribution and function in tissues remains largely unknown. Here, we present a unique analysis of human T cells in lymphoid and mucosal tissues obtained from individual organ donors, revealing tissue-intrinsic compartmentalization of naive, effector, and memory subsets conserved between diverse individuals. Effector memory CD4(+) T cells producing IL-2 predominated in mucosal tissues and accumulated as central memory subsets in lymphoid tissue, whereas CD8(+) T cells were maintained as naive subsets in lymphoid tissues and IFN-γ-producing effector memory CD8(+) T cells in mucosal sites. The T cell activation marker CD69 was constitutively expressed by memory T cells in all tissues, distinguishing them from circulating subsets, with mucosal memory T cells exhibiting additional distinct phenotypic and functional properties. Our results provide an assessment of human T cell compartmentalization as a new baseline for understanding human adaptive immunity.
Asunto(s)
Memoria Inmunológica/inmunología , Subgrupos de Linfocitos T/inmunología , Adolescente , Adulto , Factores de Edad , Antígenos CD/metabolismo , Antígenos de Diferenciación de Linfocitos T/metabolismo , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD4-Positivos/metabolismo , Linfocitos T CD8-positivos/inmunología , Linfocitos T CD8-positivos/metabolismo , Femenino , Humanos , Inmunofenotipificación , Cadenas alfa de Integrinas/metabolismo , Lectinas Tipo C/metabolismo , Masculino , Persona de Mediana Edad , Membrana Mucosa/inmunología , Especificidad de Órganos/inmunología , Subgrupos de Linfocitos T/metabolismo , Donantes de Tejidos , Adulto JovenRESUMEN
Obesity is an increasingly prevalent disease regulated by genetic and environmental factors. Emerging studies indicate that immune cells, including monocytes, granulocytes and lymphocytes, regulate metabolic homeostasis and are dysregulated in obesity. Group 2 innate lymphoid cells (ILC2s) can regulate adaptive immunity and eosinophil and alternatively activated macrophage responses, and were recently identified in murine white adipose tissue (WAT) where they may act to limit the development of obesity. However, ILC2s have not been identified in human adipose tissue, and the mechanisms by which ILC2s regulate metabolic homeostasis remain unknown. Here we identify ILC2s in human WAT and demonstrate that decreased ILC2 responses in WAT are a conserved characteristic of obesity in humans and mice. Interleukin (IL)-33 was found to be critical for the maintenance of ILC2s in WAT and in limiting adiposity in mice by increasing caloric expenditure. This was associated with recruitment of uncoupling protein 1 (UCP1)(+) beige adipocytes in WAT, a process known as beiging or browning that regulates caloric expenditure. IL-33-induced beiging was dependent on ILC2s, and IL-33 treatment or transfer of IL-33-elicited ILC2s was sufficient to drive beiging independently of the adaptive immune system, eosinophils or IL-4 receptor signalling. We found that ILC2s produce methionine-enkephalin peptides that can act directly on adipocytes to upregulate Ucp1 expression in vitro and that promote beiging in vivo. Collectively, these studies indicate that, in addition to responding to infection or tissue damage, ILC2s can regulate adipose function and metabolic homeostasis in part via production of enkephalin peptides that elicit beiging.
Asunto(s)
Tejido Adiposo Blanco/citología , Tejido Adiposo Blanco/inmunología , Inmunidad Innata/inmunología , Linfocitos/fisiología , Obesidad/inmunología , Adipocitos/citología , Adipocitos/efectos de los fármacos , Animales , Metabolismo Energético/inmunología , Encefalina Metionina/biosíntesis , Encefalina Metionina/metabolismo , Eosinófilos/inmunología , Eosinófilos/metabolismo , Femenino , Homeostasis/efectos de los fármacos , Humanos , Interleucinas/inmunología , Interleucinas/farmacología , Canales Iónicos/metabolismo , Linfocitos/citología , Linfocitos/inmunología , Masculino , Ratones , Proteínas Mitocondriales/metabolismo , Obesidad/patología , Receptores de Interleucina-4/inmunología , Receptores de Interleucina-4/metabolismo , Proteína Desacopladora 1RESUMEN
Intensified efforts to promote protective T cell-based immunity in vaccines and immunotherapies have created a compelling need to expand our understanding of human T cell function and maintenance beyond its characterization in peripheral blood. Mouse studies of T cell immunity show that, in response to infection, T cells migrate to diverse sites and persist as tissue-resident memory T cells (TRM), which mediate rapid in situ protection on antigen recall. Here we discuss new approaches to probe human T cell immunity, including novel sampling, that indicate a broad distribution and high frequency of human TRM in multiple sites. These newer findings further implicate anatomic compartmentalization as a generalized mechanism for long-term maintenance of human T cells throughout life.
Asunto(s)
Memoria Inmunológica/inmunología , Linfocitos T/inmunología , Humanos , Especificidad de Órganos , Linfocitos T/citologíaRESUMEN
Mucin type O-glycosylation is initiated by a large family of polypeptide GalNAc transferases (ppGalNAc Ts) that add α-GalNAc to the Ser and Thr residues of peptides. Of the 20 human isoforms, all but one are composed of two globular domains linked by a short flexible linker: a catalytic domain and a ricin-like lectin carbohydrate binding domain. Presently, the roles of the catalytic and lectin domains in peptide and glycopeptide recognition and specificity remain unclear. To systematically study the role of the lectin domain in ppGalNAc T glycopeptide substrate utilization, we have developed a series of novel random glycopeptide substrates containing a single GalNAc-O-Thr residue placed near either the N or C terminus of the glycopeptide substrate. Our results reveal that the presence and N- or C-terminal placement of the GalNAc-O-Thr can be important determinants of overall catalytic activity and specificity that differ between transferase isoforms. For example, ppGalNAc T1, T2, and T14 prefer C-terminally placed GalNAc-O-Thr, whereas ppGalNAc T3 and T6 prefer N-terminally placed GalNAc-O-Thr. Several transferase isoforms, ppGalNAc T5, T13, and T16, display equally enhanced N- or C-terminal activities relative to the nonglycosylated control peptides. This N- and/or C-terminal selectivity is presumably due to weak glycopeptide binding to the lectin domain, whose orientation relative to the catalytic domain is dynamic and isoform-dependent. Such N- or C-terminal glycopeptide selectivity provides an additional level of control or fidelity for the O-glycosylation of biologically significant sites and suggests that O-glycosylation may in some instances be exquisitely controlled.
Asunto(s)
Glicopéptidos , Lectinas , N-Acetilgalactosaminiltransferasas , Catálisis , Glicopéptidos/química , Glicopéptidos/genética , Glicopéptidos/metabolismo , Glicosilación , Humanos , Isoenzimas/química , Isoenzimas/genética , Isoenzimas/metabolismo , N-Acetilgalactosaminiltransferasas/química , N-Acetilgalactosaminiltransferasas/genética , N-Acetilgalactosaminiltransferasas/metabolismo , Estructura Terciaria de Proteína , Especificidad por Sustrato/fisiología , Polipéptido N-AcetilgalactosaminiltransferasaRESUMEN
T cell responses to viruses are initiated and maintained in tissue sites; however, knowledge of human antiviral T cells is largely derived from blood. Cytomegalovirus (CMV) persists in most humans, requires T cell immunity to control, yet tissue immune responses remain undefined. Here, we investigated human CMV-specific T cells, virus persistence and CMV-associated T cell homeostasis in blood, lymphoid, mucosal and secretory tissues of 44 CMV seropositive and 28 seronegative donors. CMV-specific T cells were maintained in distinct distribution patterns, highest in blood, bone marrow (BM), or lymph nodes (LN), with the frequency and function in blood distinct from tissues. CMV genomes were detected predominantly in lung and also in spleen, BM, blood and LN. High frequencies of activated CMV-specific T cells were found in blood and BM samples with low virus detection, whereas in lung, CMV-specific T cells were present along with detectable virus. In LNs, CMV-specific T cells exhibited quiescent phenotypes independent of virus. Overall, T cell differentiation was enhanced in sites of viral persistence with age. Together, our results suggest tissue T cell reservoirs for CMV control shaped by both viral and tissue-intrinsic factors, with global effects on homeostasis of tissue T cells over the lifespan.
Asunto(s)
Infecciones por Citomegalovirus/inmunología , Linfocitos T/inmunología , Linfocitos T CD8-positivos/inmunología , Citomegalovirus/inmunología , Humanos , Interferón gamma/biosíntesis , Ganglios Linfáticos/inmunología , Viremia/inmunologíaRESUMEN
B-cell responses result in clonal expansion, and can occur in a variety of tissues. To define how B-cell clones are distributed in the body, we sequenced 933,427 B-cell clonal lineages and mapped them to eight different anatomic compartments in six human organ donors. We show that large B-cell clones partition into two broad networks-one spans the blood, bone marrow, spleen and lung, while the other is restricted to tissues within the gastrointestinal (GI) tract (jejunum, ileum and colon). Notably, GI tract clones display extensive sharing of sequence variants among different portions of the tract and have higher frequencies of somatic hypermutation, suggesting extensive and serial rounds of clonal expansion and selection. Our findings provide an anatomic atlas of B-cell clonal lineages, their properties and tissue connections. This resource serves as a foundation for studies of tissue-based immunity, including vaccine responses, infections, autoimmunity and cancer.
Asunto(s)
Linfocitos B/citología , Linaje de la Célula/genética , Especificidad de Órganos/genética , Adulto , Células Clonales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Adulto JovenRESUMEN
Naïve T cells develop in the thymus and coordinate immune responses to new antigens; however, mechanisms for their long-term persistence over the human lifespan remain undefined. Here, we investigated human naïve T cell development and maintenance in primary and secondary lymphoid tissues obtained from individual organ donors aged 3 months-73 years. In the thymus, the frequency of double-positive thymocytes declined sharply in donors over age 40 coincident with reduced recent thymic emigrants (RTE) in lymphoid tissues, while naïve T cells were functionally maintained predominantly in lymph nodes (LN). Analysis of TCR clonal distribution by CDR3 sequencing of naïve CD4+ and CD8+ T cells in spleen and LNs reveal site-specific clonal expansions of naïve T cells from individuals >40 years of age with minimal clonal overlap between lymphoid tissues. We also identified biased naïve T cell clonal distribution within specific lymph nodes based on VJ usage. Together these results suggest prolonged maintenance of naïve T cells through in situ homeostasis and retention in lymphoid tissue.
RESUMEN
It is unclear how the immune response in early life becomes appropriately stimulated to provide protection while also avoiding excessive activation as a result of diverse new antigens. T cells are integral to adaptive immunity; mouse studies indicate that tissue localization of T cell subsets is important for both protective immunity and immunoregulation. In humans, however, the early development and function of T cells in tissues remain unexplored. We present here an analysis of lymphoid and mucosal tissue T cells derived from pediatric organ donors in the first two years of life, as compared to adult organ donors, revealing early compartmentalization of T cell differentiation and regulation. Whereas adult tissues contain a predominance of memory T cells, in pediatric blood and tissues the main subset consists of naive recent thymic emigrants, with effector memory T cells (T(EM)) found only in the lungs and small intestine. Additionally, regulatory T (T(reg)) cells comprise a high proportion (30-40%) of CD4(+) T cells in pediatric tissues but are present at much lower frequencies (1-10%) in adult tissues. Pediatric tissue T(reg) cells suppress endogenous T cell activation, and early T cell functionality is confined to the mucosal sites that have the lowest T(reg):T(EM) cell ratios, which suggests control in situ of immune responses in early life.
Asunto(s)
Diferenciación Celular/inmunología , Citocinas/inmunología , Tejido Linfoide/inmunología , Membrana Mucosa/inmunología , Linfocitos T/inmunología , Adolescente , Adulto , Femenino , Citometría de Flujo , Humanos , Lactante , Mucosa Intestinal/inmunología , Intestinos/inmunología , Pulmón/inmunología , Ganglios Linfáticos/inmunología , Masculino , Persona de Mediana Edad , Mucosa Respiratoria/inmunología , Bazo/inmunología , Subgrupos de Linfocitos T/inmunología , Linfocitos T Reguladores/inmunología , Timo/inmunología , Adulto JovenRESUMEN
The phagocytosis of apoptotic cells (ACs), or efferocytosis, by DCs is critical for self-tolerance and host defense. Although many efferocytosis-associated receptors have been described in vitro, the functionality of these receptors in vivo has not been explored in depth. Using a spleen efferocytosis assay and targeted genetic deletion in mice, we identified a multiprotein complex--composed of the receptor tyrosine kinase AXL, LDL receptor-related protein-1 (LRP-1), and RAN-binding protein 9 (RANBP9)--that mediates DC efferocytosis and antigen cross-presentation. We found that AXL bound ACs, but required LRP-1 to trigger internalization, in murine CD8α+ DCs and human-derived DCs. AXL and LRP-1 did not interact directly, but relied on RANBP9, which bound both AXL and LRP-1, to form the complex. In a coculture model of antigen presentation, the AXL/LRP-1/RANBP9 complex was used by DCs to cross-present AC-associated antigens to T cells. Furthermore, in a murine model of herpes simplex virus-1 infection, mice lacking DC-specific LRP-1, AXL, or RANBP9 had increased AC accumulation, defective viral antigen-specific CD8+ T cell activation, enhanced viral load, and decreased survival. The discovery of this multiprotein complex that mediates functionally important DC efferocytosis in vivo may have implications for future studies related to host defense and DC-based vaccines.