Somatic hypermutation (SHM) drives the genetic diversity of Ig genes in activated B cells and supports the generation of Abs with increased affinity for Ag. SHM is targeted to Ig genes by their enhancers (diversification activators [DIVACs]), but how the enhancers mediate this activity is unknown. We show using chicken DT40 B cells that highly active DIVACs increase the phosphorylation of RNA polymerase II (Pol II) and Pol II occupancy in the mutating gene with little or no accompanying increase in elongation-competent Pol II or production of full-length transcripts, indicating accumulation of stalled Pol II. DIVAC has similar effect also in human Ramos Burkitt lymphoma cells. The DIVAC-induced stalling is weakly associated with an increase in the detection of ssDNA bubbles in the mutating target gene. We did not find evidence for antisense transcription, or that DIVAC functions by altering levels of H3K27ac or the histone variant H3.3 in the mutating gene. These findings argue for a connection between Pol II stalling and cis-acting targeting elements in the context of SHM and thus define a mechanistic basis for locus-specific targeting of SHM in the genome. Our results suggest that DIVAC elements render the target gene a suitable platform for AID-mediated mutation without a requirement for increasing transcriptional output.

• MeSH
• aktivace lymfocytů MeSH
• Burkittův lymfom genetika   imunologie   MeSH
• cytidindeaminasa genetika   MeSH
• genetická transkripce MeSH
• imunoglobuliny genetika   metabolismus   MeSH
• kur domácí MeSH
• lidé MeSH
• mutace genetika   MeSH
• mutageneze cílená MeSH
• podskupiny B-lymfocytů imunologie   MeSH
• ptačí proteiny genetika   metabolismus   MeSH
• RNA-polymerasa II genetika   metabolismus   MeSH
• rozmanitost protilátek MeSH
• somatická hypermutace imunoglobulinových genů MeSH
• zesilovače transkripce genetika   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Since the publication of the first chicken genome sequence, we have encountered genes playing key roles in mammalian immunology, but being seemingly absent in birds. One of those was, until recently, Foxp3, the master transcription factor of regulatory T cells in mammals. Therefore, avian regulatory T cell research is still poorly standardized. In this study we identify a chicken ortholog of Foxp3 We prove sequence homology with known mammalian and sauropsid sequences, but also reveal differences in major domains. Expression profiling shows an association of Foxp3 and CD25 expression levels in CD4+CD25+ peripheral T cells and identifies a CD4-CD25+Foxp3high subset of thymic lymphocytes that likely represents yet undescribed avian regulatory T precursor cells. We conclude that Foxp3 is existent in chickens and that it shares certain functional characteristics with its mammalian ortholog. Nevertheless, pathways for regulatory T cell development and Foxp3 function are likely to differ between mammals and birds. The identification and characterization of chicken Foxp3 will help to define avian regulatory T cells and to analyze their functional properties and thereby advance the field of avian immunology.

• MeSH
• aktivace lymfocytů imunologie   MeSH
• buněčná diferenciace imunologie   MeSH
• forkhead transkripční faktory genetika   MeSH
• genom genetika   MeSH
• kur domácí genetika   imunologie   MeSH
• receptor interleukinu-2 - alfa-podjednotka metabolismus   MeSH
• regulační T-lymfocyty imunologie   MeSH
• sekvence aminokyselin genetika   MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• sekvenční homologie MeSH
• sekvenční seřazení MeSH
• stanovení celkové genové exprese MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Ag-inexperienced memory-like T (AIMT) cells are functionally unique T cells, representing one of the two largest subsets of murine CD8+ T cells. However, differences between laboratory inbred strains, insufficient data from germ-free mice, a complete lack of data from feral mice, and an unclear relationship between AIMT cells formation during aging represent major barriers for better understanding of their biology. We performed a thorough characterization of AIMT cells from mice of different genetic background, age, and hygienic status by flow cytometry and multiomics approaches, including analyses of gene expression, TCR repertoire, and microbial colonization. Our data showed that AIMT cells are steadily present in mice, independent of their genetic background and hygienic status. Despite differences in their gene expression profiles, young and aged AIMT cells originate from identical clones. We identified that CD122 discriminates two major subsets of AIMT cells in a strain-independent manner. Whereas thymic CD122LOW AIMT cells (innate memory) prevail only in young animals with high thymic IL-4 production, peripheral CD122HIGH AIMT cells (virtual memory) dominate in aged mice. Cohousing with feral mice changed the bacterial colonization of laboratory strains but had only minimal effects on the CD8+ T cell compartment, including AIMT cells.

• MeSH
• antigeny genetika   imunologie   MeSH
• fenotyp MeSH
• imunologická paměť genetika   imunologie   MeSH
• klonální evoluce MeSH
• myši inbrední BALB C MeSH
• myši inbrední C57BL MeSH
• myši transgenní MeSH
• myši MeSH
• nestabilita genomu MeSH
• stárnutí genetika   imunologie   MeSH
• T-lymfocyty imunologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Despite high vaccine coverage in many parts of the world, pertussis is resurging in a number of areas in which acellular vaccines are the primary vaccine administered to infants and young children. This is attributed in part to the suboptimal and short-lived immunity elicited by acellular pertussis vaccines and to their inability to prevent nasal colonization and transmission of the etiologic agent Bordetella pertussis In response to this escalating public health concern, the National Institute of Allergy and Infectious Diseases held the workshop "Overcoming Waning Immunity in Pertussis Vaccines" in September 2019 to identify issues and possible solutions for the defects in immunity stimulated by acellular pertussis vaccines. Discussions covered aspects of the current problem, gaps in knowledge and possible paths forward. This review summarizes presentations and discussions of some of the key points that were raised by the workshop.

• MeSH
• acelulární vakcíny imunologie   MeSH
• Bordetella pertussis imunologie   MeSH
• lidé MeSH
• National Institute of Allergy and Infectious Diseases (U.S.) MeSH
• pertuse imunologie   MeSH
• pertusová vakcína imunologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Research Support, N.I.H., Extramural MeSH
• Geografické názvy
• Spojené státy americké MeSH

Autoinflammatory diseases are characterized by dysregulation of the innate immune system, leading to spontaneous inflammation. Pstpip2cmo mouse strain is a well-characterized model of this class of disorders. Because of the mutation leading to the lack of adaptor protein PSTPIP2, these animals suffer from autoinflammatory chronic multifocal osteomyelitis similar to several human syndromes. Current evidence suggests that it is driven by hyperproduction of IL-1β by neutrophil granulocytes. In this study, we show that in addition to IL-1β, PSTPIP2 also negatively regulates pathways governing reactive oxygen species generation by neutrophil NOX2 NADPH oxidase. Pstpip2cmo neutrophils display highly elevated superoxide production in response to a range of stimuli. Inactivation of NOX2 NADPH oxidase in Pstpip2cmo mice did not affect IL-1β levels, and the autoinflammatory process was initiated with similar kinetics. However, the bone destruction was almost completely alleviated, suggesting that dysregulated NADPH oxidase activity is a key factor promoting autoinflammatory bone damage in Pstpip2cmo mice.

• MeSH
• adaptorové proteiny signální transdukční genetika   metabolismus   MeSH
• buněčné linie MeSH
• cytoskeletální proteiny genetika   metabolismus   MeSH
• interleukin-1beta imunologie   metabolismus   MeSH
• kosti a kostní tkáň imunologie   patologie   MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• mutace MeSH
• myši transgenní MeSH
• myši MeSH
• NADPH-oxidasa 2 genetika   metabolismus   MeSH
• neutrofily imunologie   metabolismus   MeSH
• osteomyelitida genetika   imunologie   patologie   MeSH
• primární buněčná kultura MeSH
• signální transdukce genetika   imunologie   MeSH
• superoxidy imunologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Common variable immunodeficiency disorders (CVID) represent a group of primary immunodeficiency diseases characterized by hypogammaglobulinemia and impaired specific Ab response, resulting in recurrent infections due to dysfunctional immune response. The specific mechanisms mediating immune deficiency in CVID remain to be determined. Previous studies indicated that immune dysregulation in CVID patients is associated with chronic microbial translocation, systemic immune activation, and altered homeostasis of lymphocytic and myeloid lineages. A detailed phenotypic, functional characterization of plasma markers and immune cell populations was performed in 46 CVID patients and 44 healthy donors. CVID patients displayed significantly elevated plasma levels of a marker of neutrophil activation neutrophil gelatinase-associated lipocalin. Neutrophils from CVID patients exhibited elevated surface levels of CD11b and PD-L1 and decreased levels of CD62L, CD16, and CD80, consistent with a phenotype of activated neutrophils with suppressive properties. Neutrophils from CVID patients actively suppressed T cell activation and release of IFN-γ via the production of reactive oxygen species. Furthermore, CVID was associated with an increased frequency of low-density neutrophils (LDNs)/granulocytic myeloid-derived suppressor cells. LDN/granulocytic myeloid-derived suppressor cell frequency in CVID patients correlated with reduced T cell responsiveness. Exogenous stimulation of whole blood with bacterial LPS emulated some but not all of the phenotypic changes observed on neutrophils from CVID patients and induced neutrophil population with LDN phenotype. The presented data demonstrate that neutrophils in the blood of CVID patients acquire an activated phenotype and exert potent T cell suppressive activity. Specific targeting of myeloid cell-derived suppressor activity represents a novel potential therapeutic strategy for CVID.

• MeSH
• aktivace neutrofilů MeSH
• antigeny CD11b metabolismus   MeSH
• antigeny CD274 metabolismus   MeSH
• běžná variabilní imunodeficience imunologie   MeSH
• dospělí MeSH
• granulocyty fyziologie   MeSH
• imunologická tolerance MeSH
• kultivované buňky MeSH
• lidé středního věku MeSH
• lidé MeSH
• lipokalin-2 krev   MeSH
• mladý dospělý MeSH
• myeloidní supresorové buňky fyziologie   MeSH
• neutrofily fyziologie   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• T-lymfocyty imunologie   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

In mice, the ability of naive T (TN) cells to mount an effector response correlates with TCR sensitivity for self-derived Ags, which can be quantified indirectly by measuring surface expression levels of CD5. Equivalent findings have not been reported previously in humans. We identified two discrete subsets of human CD8+ TN cells, defined by the absence or presence of the chemokine receptor CXCR3. The more abundant CXCR3+ TN cell subset displayed an effector-like transcriptional profile and expressed TCRs with physicochemical characteristics indicative of enhanced interactions with peptide-HLA class I Ags. Moreover, CXCR3+ TN cells frequently produced IL-2 and TNF in response to nonspecific activation directly ex vivo and differentiated readily into Ag-specific effector cells in vitro. Comparative analyses further revealed that human CXCR3+ TN cells were transcriptionally equivalent to murine CXCR3+ TN cells, which expressed high levels of CD5. These findings provide support for the notion that effector differentiation is shaped by heterogeneity in the preimmune repertoire of human CD8+ T cells.

• MeSH
• aktivace lymfocytů imunologie   MeSH
• biologické markery MeSH
• buněčná diferenciace imunologie   MeSH
• CD8-pozitivní T-lymfocyty imunologie   metabolismus   MeSH
• dospělí MeSH
• imunofenotypizace MeSH
• imunologická paměť MeSH
• kultivované buňky MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• myši MeSH
• receptory CXCR3 metabolismus   MeSH
• senioři MeSH
• T-lymfocyty - podskupiny imunologie   metabolismus   MeSH
• věkové faktory MeSH
• zvířata MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• myši MeSH
• senioři MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Intramural MeSH

Development of lymphoid progenitors requires a coordinated regulation of gene expression, DNA replication, and gene rearrangement. Chromatin-remodeling activities directed by SWI/SNF2 superfamily complexes play important roles in these processes. In this study, we used a conditional knockout mouse model to investigate the role of Smarca5, a member of the ISWI subfamily of such complexes, in early lymphocyte development. Smarca5 deficiency results in a developmental block at the DN3 stage of αβ thymocytes and pro-B stage of early B cells at which the rearrangement of Ag receptor loci occurs. It also disturbs the development of committed (CD73+) γδ thymocytes. The αβ thymocyte block is accompanied by massive apoptotic depletion of β-selected double-negative DN3 cells and premitotic arrest of CD4/CD8 double-positive cells. Although Smarca5-deficient αβ T cell precursors that survived apoptosis were able to undergo a successful TCRβ rearrangement, they exhibited a highly abnormal mRNA profile, including the persistent expression of CD44 and CD25 markers characteristic of immature cells. We also observed that the p53 pathway became activated in these cells and that a deficiency of p53 partially rescued the defect in thymus cellularity (in contrast to early B cells) of Smarca5-deficient mice. However, the activation of p53 was not primarily responsible for the thymocyte developmental defects observed in the Smarca5 mutants. Our results indicate that Smarca5 plays a key role in the development of thymocytes undergoing β-selection, γδ thymocytes, and also B cell progenitors by regulating the transcription of early differentiation programs.

• MeSH
• adenosintrifosfatasy genetika   metabolismus   MeSH
• B-lymfocyty fyziologie   MeSH
• buněčná diferenciace MeSH
• chromozomální proteiny, nehistonové genetika   metabolismus   MeSH
• genová přestavba MeSH
• klonální selekce zprostředkovaná antigeny MeSH
• kultivované buňky MeSH
• lymfoidní progenitorové buňky fyziologie   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• nádorový supresorový protein p53 metabolismus   MeSH
• receptory antigenů B-buněk genetika   metabolismus   MeSH
• receptory antigenů T-buněk alfa-beta genetika   metabolismus   MeSH
• receptory antigenů T-buněk gama-delta genetika   metabolismus   MeSH
• T-lymfocyty fyziologie   MeSH
• thymocyty fyziologie   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Surface IgD is coexpressed with IgM on naive mature B cells. Still, the role of surface IgD remains enigmatic even 50 y after its initial discovery. In this study, we examined the in vivo role of surface IgD in human B cell homeostasis and Ab responses in four individuals with heterozygous nonsense mutations in IGHD All IGHD heterozygous individuals had normal numbers of B cells and serum Igs and did not show signs of immunodeficiency or immune dysregulation. IgD+ and IgD- naive mature B cells were present in equal numbers and showed similar immunophenotypes, except for decreased expression of CD79b in the IgD- subset. Furthermore, both IgD+ and IgD- naive mature B cells had normal replication histories and similar capacities to differentiate into plasma cells upon in vitro stimulation, and Ig class-switched memory B cells showed similar levels of somatic hypermutations. Thus, human B cells lacking IgD expression develop normally and generate immunological memory in vivo, suggesting that surface IgD might function more restrictedly in regulating of B cell activation to specific antigenic structures.

• MeSH
• aktivace lymfocytů MeSH
• B-lymfocyty imunologie   MeSH
• buněčná diferenciace MeSH
• haploinsuficience MeSH
• homeostáza MeSH
• imunoglobulin D genetika   metabolismus   MeSH
• imunoglobulin M metabolismus   MeSH
• imunologická paměť MeSH
• kultivované buňky MeSH
• lidé MeSH
• membránové proteiny metabolismus   MeSH
• plazmatické buňky imunologie   MeSH
• podskupiny B-lymfocytů imunologie   MeSH
• přesmyk imunoglobulinových tříd MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

IL-2 has been used to treat diseases ranging from cancer to autoimmune disorders, but its concurrent immunostimulatory and immunosuppressive effects hinder efficacy. IL-2 orchestrates immune cell function through activation of a high-affinity heterotrimeric receptor (composed of IL-2Rα, IL-2Rβ, and common γ [γc]). IL-2Rα, which is highly expressed on regulatory T (TReg) cells, regulates IL-2 sensitivity. Previous studies have shown that complexation of IL-2 with the JES6-1 Ab preferentially biases cytokine activity toward TReg cells through a unique mechanism whereby IL-2 is exchanged from the Ab to IL-2Rα. However, clinical adoption of a mixed Ab/cytokine complex regimen is limited by stoichiometry and stability concerns. In this study, through structure-guided design, we engineered a single agent fusion of the IL-2 cytokine and JES6-1 Ab that, despite being covalently linked, preserves IL-2 exchange, selectively stimulating TReg expansion and exhibiting superior disease control to the mixed IL-2/JES6-1 complex in a mouse colitis model. These studies provide an engineering blueprint for resolving a major barrier to the implementation of functionally similar IL-2/Ab complexes for treatment of human disease.

• MeSH
• aktivace lymfocytů MeSH
• autoimunitní nemoci imunologie   terapie   MeSH
• cytokiny genetika   imunologie   metabolismus   MeSH
• imunoterapie metody   MeSH
• kolitida imunologie   terapie   MeSH
• kultivované buňky MeSH
• lidé MeSH
• modely nemocí na zvířatech MeSH
• myši MeSH
• proliferace buněk MeSH
• proteinové inženýrství MeSH
• protilátky genetika   metabolismus   MeSH
• receptory interleukinu-2 imunologie   MeSH
• regulační T-lymfocyty imunologie   MeSH
• rekombinantní fúzní proteiny genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH