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1.
Immunity ; 46(5): 804-817.e7, 2017 05 16.
Artículo en Inglés | MEDLINE | ID: mdl-28514687

RESUMEN

The development of soluble envelope glycoprotein (Env) mimetics displaying ordered trimeric symmetry has ushered in a new era in HIV-1 vaccination. The recently reported native, flexibly linked (NFL) design allows the generation of native-like trimers from clinical isolates at high yields and homogeneity. As the majority of infections world-wide are of the clade C subtype, we examined responses in non-human primates to well-ordered subtype C 16055 trimers administered in soluble or high-density liposomal formats. We detected superior germinal center formation and enhanced autologous neutralizing antibodies against the neutralization-resistant (tier 2) 16055 virus following inoculation of liposome-arrayed trimers. Epitope mapping of the neutralizing monoclonal antibodies (mAbs) indicated major contacts with the V2 apex, and 3D electron microscopy reconstructions of Fab-trimer complexes revealed a horizontal binding angle to the Env spike. These vaccine-elicited mAbs target the V2 cap, demonstrating a means to accomplish tier 2 virus neutralization by penetrating the dense N-glycan shield.


Asunto(s)
Anticuerpos Neutralizantes/inmunología , Anticuerpos Anti-VIH/inmunología , VIH-1/inmunología , Fragmentos de Péptidos/inmunología , Multimerización de Proteína/inmunología , Productos del Gen env del Virus de la Inmunodeficiencia Humana/química , Productos del Gen env del Virus de la Inmunodeficiencia Humana/inmunología , Anticuerpos Neutralizantes/química , Anticuerpos Neutralizantes/metabolismo , Mapeo Epitopo , Epítopos/química , Epítopos/inmunología , Anticuerpos Anti-VIH/química , Anticuerpos Anti-VIH/metabolismo , VIH-1/clasificación , VIH-1/genética , Humanos , Inmunización , Modelos Moleculares , Simulación del Acoplamiento Molecular , Fragmentos de Péptidos/química , Fragmentos de Péptidos/metabolismo , Unión Proteica , Conformación Proteica , Virión/química , Virión/inmunología , Virión/ultraestructura , Productos del Gen env del Virus de la Inmunodeficiencia Humana/genética
2.
Semin Liver Dis ; 43(2): 149-162, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-37156523

RESUMEN

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disorder. Increased sympathetic (noradrenergic) nerve tone has a complex role in the etiopathomechanism of NAFLD, affecting the development/progression of steatosis, inflammation, fibrosis, and liver hemodynamical alterations. Also, lipid sensing by vagal afferent fibers is an important player in the development of hepatic steatosis. Moreover, disorganization and progressive degeneration of liver sympathetic nerves were recently described in human and experimental NAFLD. These structural alterations likely come along with impaired liver sympathetic nerve functionality and lack of adequate hepatic noradrenergic signaling. Here, we first overview the anatomy and physiology of liver nerves. Then, we discuss the nerve impairments in NAFLD and their pathophysiological consequences in hepatic metabolism, inflammation, fibrosis, and hemodynamics. We conclude that further studies considering the spatial-temporal dynamics of structural and functional changes in the hepatic nervous system may lead to more targeted pharmacotherapeutic advances in NAFLD.


Asunto(s)
Enfermedad del Hígado Graso no Alcohólico , Humanos , Fibrosis , Inflamación/metabolismo , Hígado/patología , Enfermedad del Hígado Graso no Alcohólico/metabolismo
3.
J Immunol ; 206(5): 999-1012, 2021 03 01.
Artículo en Inglés | MEDLINE | ID: mdl-33472907

RESUMEN

Vaccine efforts to combat HIV are challenged by the global diversity of viral strains and shielding of neutralization epitopes on the viral envelope glycoprotein trimer. Even so, the isolation of broadly neutralizing Abs from infected individuals suggests the potential for eliciting protective Abs through vaccination. This study reports a panel of 58 mAbs cloned from a rhesus macaque (Macaca mulatta) immunized with envelope glycoprotein immunogens curated from an HIV-1 clade C-infected volunteer. Twenty mAbs showed neutralizing activity, and the strongest neutralizer displayed 92% breadth with a median IC50 of 1.35 µg/ml against a 13-virus panel. Neutralizing mAbs predominantly targeted linear epitopes in the V3 region in the cradle orientation (V3C) with others targeting the V3 ladle orientation (V3L), the CD4 binding site (CD4bs), C1, C4, or gp41. Nonneutralizing mAbs bound C1, C5, or undetermined conformational epitopes. Neutralization potency strongly correlated with the magnitude of binding to infected primary macaque splenocytes and to the level of Ab-dependent cellular cytotoxicity, but did not predict the degree of Ab-dependent cellular phagocytosis. Using an individualized germline gene database, mAbs were traced to 23 of 72 functional IgHV alleles. Neutralizing V3C Abs displayed minimal nucleotide somatic hypermutation in the H chain V region (3.77%), indicating that relatively little affinity maturation was needed to achieve in-clade neutralization breadth. Overall, this study underscores the polyfunctional nature of vaccine-elicited tier 2-neutralizing V3 Abs and demonstrates partial reproduction of the human donor's humoral immune response through nonhuman primate vaccination.


Asunto(s)
Anticuerpos Neutralizantes/inmunología , Anticuerpos Anti-VIH/inmunología , VIH-1/inmunología , Productos del Gen env del Virus de la Inmunodeficiencia Humana/inmunología , Vacunas contra el SIDA/inmunología , Animales , Anticuerpos Monoclonales/inmunología , Sitios de Unión/inmunología , Línea Celular , Epítopos/inmunología , Infecciones por VIH/inmunología , Humanos , Inmunización/métodos , Región Variable de Inmunoglobulina/inmunología , Macaca mulatta/inmunología , Células THP-1/inmunología , Vacunación/métodos , Proteínas del Envoltorio Viral/inmunología
4.
Eur J Immunol ; 51(2): 445-458, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-32920851

RESUMEN

B lymphocytes are among the cell types whose effector functions are modulated by mast cells (MCs). The B/MC crosstalk emerged in several pathological settings, notably the colon of inflammatory bowel disease (IBD) patients is a privileged site in which MCs and IgA+ cells physically interact. Herein, by inducing conditional depletion of MCs in red MC and basophil (RMB) mice, we show that MCs control B cell distribution in the gut and IgA serum levels. Moreover, in dextran sulfate sodium (DSS)-treated RMB mice, the presence of MCs is fundamental for the enlargement of the IgA+ population in the bowel and the increase of systemic IgA production. Since both conventional B-2 and peritoneal-derived B cells populate the intestine and communicate with MCs in physiological conditions and during inflammation, we further explored this interplay through the use of co-cultures. We show that MCs finely regulate different aspects of splenic B cell biology while peritoneal B cells are unresponsive to the supporting effects provided by MCs. Interestingly, peritoneal B cells induce a pro-inflammatory skewing in MCs, characterized by increased ST2 and TNF-α expression. Altogether, this study uncovers the versatility of the B/MC liaison and highlights key aspects for the resolution of intestinal inflammation.


Asunto(s)
Linfocitos B/metabolismo , Colon/inmunología , Inmunoglobulina A/inmunología , Mucosa Intestinal/inmunología , Mastocitos/inmunología , Animales , Colitis/inmunología , Colon/microbiología , Sulfato de Dextran/inmunología , Microbioma Gastrointestinal/inmunología , Inflamación/inmunología , Inflamación/microbiología , Enfermedades Inflamatorias del Intestino/inmunología , Enfermedades Inflamatorias del Intestino/microbiología , Mucosa Intestinal/microbiología , Ratones , Ratones Endogámicos C57BL , Factor de Necrosis Tumoral alfa/inmunología
5.
Cell Immunol ; 375: 104516, 2022 05.
Artículo en Inglés | MEDLINE | ID: mdl-35413621

RESUMEN

Mutations causing loss of the NF-κB regulator IκBNS, result in impaired development of innate-like B cells and defective plasma cell (PC) differentiation. Since productive PC differentiation requires B cell metabolic reprogramming, we sought to investigate processes important for this transition using the bumble mouse strain, deficient for IκBNS. We report that LPS-activated bumble B cells exhibited elevated mTOR activation levels, mitochondrial accumulation, increased OXPHOS and mROS production, along with a reduced capacity for autophagy, compared to wildtype B cells. Overall, our results demonstrate that PC differentiation in the absence of IκBNS is characterized by excessive activation during early rounds of B cell division, increased mitochondrial metabolism and decreased autophagic capacity, thus improving our understanding of the role of IκBNS in PC differentiation.


Asunto(s)
Activación de Linfocitos , FN-kappa B , Animales , Diferenciación Celular/genética , Ratones , Ratones Noqueados , FN-kappa B/metabolismo , Estrés Oxidativo
6.
Immunol Cell Biol ; 99(2): 234-243, 2021 02.
Artículo en Inglés | MEDLINE | ID: mdl-32888232

RESUMEN

Marginal zone (MZ) B cells are innate-like B cells that produce polyreactive antibodies with an affinity for microbial molecular patterns and carbohydrate ligands. MZ B cells have been shown to be important in mediating immunity to various bacteria including Streptococcus pneumoniae and are also implicated in inflammatory syndromes including lupus erythematosus. The intestinal microbiota is responsible for producing short-chain fatty acids, which can regulate immune cell function by several mechanisms including ligation of the G-protein-coupled receptor (GPR)43. Herein, we show that MZ B cells express Gpr43 messenger RNA and that the absence of this receptor impacts on MZ B-cell surface marker expression and antibody production. In T-cell-independent responses to the hapten 4-hydroxy-3-nitrophenylacetic acid (NP), mice deficient in GPR43 displayed higher serum titers of NP-specific antibodies. Moreover, in response to a pneumococcal polysaccharide vaccine, GPR43-deficient mice developed robust serum antibody responses and had markedly increased numbers of splenic antibody-secreting cells, compared with control mice. Finally, serum immunoglobulin M autoantibodies to double-stranded DNA and phosphatidylcholine were increased in resting 10-15-week-old mice lacking GPR43. Taken together, mice lacking GPR43 have heightened antibody responses to T-cell-independent antigens, which may be a result of impaired regulation of MZ B cells.


Asunto(s)
Linfocitos B , Ácidos Grasos Volátiles , Animales , Células Productoras de Anticuerpos , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados
7.
J Immunol ; 200(2): 775-787, 2018 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-29222168

RESUMEN

Marginal zone (MZ) B cells reside in the splenic MZ and play important roles in T cell-independent humoral immune responses against blood-borne pathogens. IκBNS-deficient bumble mice exhibit a severe reduction in the MZ B compartment but regain an MZ B population with age and, thus, represent a valuable model to examine the biology of MZ B cells. In this article, we characterized the MZ B cell defect in further detail and investigated the nature of the B cells that appear in the MZ of aged bumble mice. Flow cytometry analysis of the splenic transitional B cell subsets demonstrated that MZ B cell development was blocked at the transitional-1 to transitional-2-MZ precursor stage in the absence of functional IκBNS. Immunohistochemical analysis of spleen sections from wild-type and bumble mice revealed no alteration in the cellular MZ microenvironment, and analysis of bone marrow chimeras indicated that the MZ B cell development defect in bumble mice was B cell intrinsic. Further, we demonstrate that the B cells that repopulate the MZ in aged bumble mice were distinct from age-matched wild-type MZ B cells. Specifically, the expression of surface markers characteristic for MZ B cells was altered and the L chain Igλ+ repertoire was reduced in bumble mice. Finally, plasma cell differentiation of sorted LPS-stimulated MZ B cells was impaired, and aged bumble mice were unable to respond to NP-Ficoll immunization. These results demonstrate that IκBNS is required for an intact MZ B cell compartment in C57BL/6 mice.


Asunto(s)
Subgrupos de Linfocitos B/inmunología , Subgrupos de Linfocitos B/metabolismo , Selección Clonal Mediada por Antígenos , Quinasa I-kappa B/deficiencia , Bazo/inmunología , Bazo/metabolismo , Factores de Edad , Animales , Antígenos T-Independientes/inmunología , Subgrupos de Linfocitos B/citología , Biomarcadores , Diferenciación Celular , Inmunoglobulina G/genética , Inmunoglobulina G/inmunología , Inmunofenotipificación , Lipopolisacáridos/inmunología , Ratones , Ratones Noqueados , Fenotipo
8.
Immunol Cell Biol ; 97(5): 485-497, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30597621

RESUMEN

Impaired classical NF-κB pathway signaling causes reduced antibody responses to T-independent (TI) antigens. We investigated the potential reasons for defective TI responses in mice lacking the atypical inhibitory kappa B (IκB) protein of the NF-κB pathway, IκBNS. Analyses of the plasma cell compartment in vitro and in vivo after challenge with lipopolysaccharide (LPS) showed significant decreases in the frequencies of plasma cells in the absence of IκBNS. In vitro activation of B cells via the B cell receptor or via Toll-like receptor 4 revealed that early activation events were unaffected in IκBNS-deficient B cells, while proliferation was reduced compared to in similarly stimulated wildtype (wt) B cells. IκBNS-deficient B cells also displayed impaired upregulation of the transmembrane activator and calcium modulator cyclophilin ligand interactor (TACI), which is essential for TI responses, and decreased sensitivity to TACI ligands upon stimulation. Furthermore, IκBNS-deficient B cells, in contrast to wt B cells, displayed altered expression of IRF4, Blimp-1 and Pax5 upon LPS-induced differentiation, indicating impaired transcriptional regulation of plasma cell generation.


Asunto(s)
Diferenciación Celular , Regulación de la Expresión Génica/inmunología , Proteínas I-kappa B/deficiencia , Células Plasmáticas/inmunología , Proteína Activadora Transmembrana y Interactiva del CAML/inmunología , Animales , Diferenciación Celular/genética , Diferenciación Celular/inmunología , Proteínas I-kappa B/inmunología , Ratones , Ratones Noqueados , Células Plasmáticas/citología , Receptor Toll-Like 4/genética , Receptor Toll-Like 4/inmunología , Proteína Activadora Transmembrana y Interactiva del CAML/genética
9.
Proc Natl Acad Sci U S A ; 111(39): E4119-26, 2014 Sep 30.
Artículo en Inglés | MEDLINE | ID: mdl-25228759

RESUMEN

B-1 cells mediate early protection against infection by responding to T cell-independent (TI) antigens found on the surface of various pathogens. Mice with impaired expression of the atypical IκB protein IκBNS have markedly reduced frequencies of B-1 cells. We used a mouse strain with dysfunctional IκBNS derived from an N-ethyl-N-nitrosourea (ENU) screen, named bumble, to investigate the point in the development of B-1 cells where IκBNS is required. The presence of wild-type (wt) peritoneal cells in mixed wt/bumble chimeras did not rescue the development of bumble B-1 cells, but wt peritoneal cells transferred to bumble mice restored natural IgM levels and response to TI antigens. The bumble and wt mice displayed similar levels of fetal liver B-1 progenitors and splenic neonatal transitional B (TrB) cells, both of which were previously shown to give rise to B-1 cells. Interestingly, we found that a subset of wt neonatal TrB cells expressed common B-1a markers (TrB-1a) and that this cell population was absent in the bumble neonatal spleen. Sorted TrB-1a (CD93(+)IgM(+)CD5(+)) cells exclusively generated B-1a cells when adoptively transferred, whereas sorted CD93(+)IgM(+)CD5(-) cells gave rise to B-2 cells and, to a lesser extent, B-1b and B-1a cells. This study identifies a phenotypically distinct splenic population of TrB-1a cells and establishes that the development of B-1a cells is blocked before this stage in the absence of IκBNS.


Asunto(s)
Subgrupos de Linfocitos B/inmunología , Proteínas I-kappa B/deficiencia , Proteínas/inmunología , Traslado Adoptivo , Animales , Animales Recién Nacidos , Antígenos T-Independientes/administración & dosificación , Subgrupos de Linfocitos B/citología , Subgrupos de Linfocitos B/metabolismo , Diferenciación Celular/inmunología , Proteínas I-kappa B/genética , Proteínas I-kappa B/inmunología , Inmunoglobulina M/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Fenotipo , Proteínas/genética
10.
Immunol Cell Biol ; 93(2): 136-46, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25310967

RESUMEN

Signalling through Toll-like receptors (TLRs) by endogenous components of viruses or bacteria can promote antibody (Ab) isotype switching to IgG2a/c. Multiple cell types are capable of responding to TLR stimulation in vivo and the processes underlying TLR-induced Ab isotype switching are not fully defined. Here, we used feeble mice, which are deficient in the peptide/histidine transporter solute carrier family 15 member 4 (Slc15a4), and fail to produce cytokines including interferon alpha (IFNα) in response to TLR9 stimulation, to study Ab isotype switching to IgG2c in response to vaccination. We demonstrate that the production of IgG2c in response to CpGA-adjuvanted vaccines was severely reduced in feeble mice, while a more subtle defect was observed for CpGB. The reduced IgG2c production in feeble could not be ascribed to defective plasmacytoid dendritic cell (pDC) responses alone as we found that splenic cDCs and B cells from feeble mice were also defective in response to TLR9 ligation ex vivo. We conclude that Slc15a4 is required for intact function of TLR9-expressing cells and for effective Ab isotype switching to IgG2c in response to CpG-adjuvanted vaccines.


Asunto(s)
Cambio de Clase de Inmunoglobulina , Proteínas de Transporte de Membrana/metabolismo , Receptores de IgG/metabolismo , Recombinación Genética , Receptor Toll-Like 9/metabolismo , Adyuvantes Inmunológicos/farmacología , Animales , Formación de Anticuerpos/efectos de los fármacos , Linfocitos B/efectos de los fármacos , Linfocitos B/inmunología , Proliferación Celular/efectos de los fármacos , Células Dendríticas/efectos de los fármacos , Células Dendríticas/inmunología , Epítopos/inmunología , Inmunización , Cambio de Clase de Inmunoglobulina/efectos de los fármacos , Subgrupos Linfocitarios/efectos de los fármacos , Subgrupos Linfocitarios/inmunología , Ratones Endogámicos BALB C , Ratones Endogámicos C57BL , Oligodesoxirribonucleótidos/farmacología , Recombinación Genética/efectos de los fármacos , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología
11.
J Virol ; 88(6): 3235-45, 2014 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24390326

RESUMEN

UNLABELLED: Human B cells, the main target of Epstein-Barr virus (EBV), can display several types of latent viral protein expression, denoted 0, I, IIa, IIb, or III. Of these, only type III expression induces proliferation of cells in vitro. These latency types are present at specific stages of infection and are also characteristic of different tumor types, but their generation is not fully understood. In this study, we analyzed the role of T cells in the regulation of EBV viral latency by using humanized NOD/SCID/IL2Rγ(-/-) mice. Several spleens presented macroscopic tumors 4 weeks after infection. Explanted spleen B cells from some of the EBV-infected mice proliferated in vitro, but this was usually lowered when cyclosporine was added to the cultures. This suggested that the in vitro growth of EBV-infected B cells required T cell help; thus, cells other than type III cells were also present in the spleens. Quantitative PCR analysis of promoter activities specific for the different EBV latency types confirmed that in addition to type III cells, type IIa and type I cells were present in the spleen. The relative usage of the viral promoter specific for I and IIa latency types (Q promoter) was higher in CD8(+) cell-depleted mice, and it was absent from CD4(+) cell-depleted mice. These results indicate that CD4(+) T cells are necessary for the generation/maintenance of cells with latency I/IIa in the humanized mice. CD4(+) T cells contributed to this process through their CD40L expression. IMPORTANCE: At primary infection with EBV, the infected B cells are proliferating and express viral proteins that have transforming potential. However, when the acute infection is resolved, in healthy individuals EBV is carried by a small fraction of B cells that express a restricted number of viral proteins unable to induce proliferation. Understanding the details of this transition is of fundamental importance. We studied this question in humanized mice by manipulating their different T cell compartments before and during infection with EBV. Our results indicate that CD4(+) T cells are responsible for the switch to a nonproliferating EBV program during primary infection with EBV.


Asunto(s)
Infecciones por Virus de Epstein-Barr/inmunología , Herpesvirus Humano 4/fisiología , Linfocitos T/inmunología , Latencia del Virus , Animales , Infecciones por Virus de Epstein-Barr/virología , Herpesvirus Humano 4/genética , Humanos , Ratones , Ratones Endogámicos NOD , Ratones SCID , Regiones Promotoras Genéticas , Proteínas Virales/genética , Proteínas Virales/metabolismo
12.
Proc Natl Acad Sci U S A ; 109(5): 1512-7, 2012 Jan 31.
Artículo en Inglés | MEDLINE | ID: mdl-22307606

RESUMEN

Following infection with Epstein-Barr virus (EBV), the virus is carried for life in the memory B-cell compartment in a silent state (latency I/0). These cells do not resemble the proliferating lymphoblastoid cells (LCLs) (latency III) that are generated after infection. It is of fundamental significance to identify how the different EBV expression patterns are established in the latently infected cell. In view of the prompt activatability of CD4(+) T cells in primary EBV infection, and their role in B-cell differentiation, we studied the involvement of CD4(+) T cells in the regulation of EBV latency. Lymphoblastoid cell lines (LCLs) were cocultured with autologous or allogeneic CD4(+) T cells. Activated T cells influenced the expression of two key viral proteins that determine the fate of the infected B cell. EBNA2 was down-regulated, whereas LMP1 was unregulated and the cells proliferated less. This was paralleled by the down-regulation of the latency III promoter (Cp). Experiments performed in the transwell system showed that this change does not require cell contact, but it is mediated by soluble factors. Neutralizing experiments proved that the up-regulation of LMP1 is, to some extent, mediated by IL21, but this cytokine was not responsible for EBNA2 down-regulation. This effect was partly mediated by soluble CD40L. We detected similar regulatory functions of T cells in in vitro-infected lymphocyte populations. In conclusion, our results revealed an additional mechanism by which CD4(+) T cells can control the EBV-induced B-cell proliferation.


Asunto(s)
Linfocitos T CD4-Positivos/metabolismo , Herpesvirus Humano 4/fisiología , Latencia del Virus , Linfocitos T CD4-Positivos/citología , Técnicas de Cocultivo , Humanos , Activación de Linfocitos , Solubilidad
13.
Immunology ; 141(2): 181-91, 2014 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24116744

RESUMEN

Anti-citrullinated peptide/protein antibodies (ACPAs) are highly sensitive and specific markers of rheumatoid arthritis (RA). Identification of peptide epitopes that may detect different subgroups of RA patients might have diagnostic and prognostic significance. We have investigated citrulline- and arginine-containing peptide pairs derived from filaggrin, collagen or vimentin, and compared this citrulline-peptide panel with the serological assays conventionally used to detect ACPAs. Furthermore, we studied if the same citrulline-peptides identify antibody-secreting cells in in vitro cultures of RA B cells. Recognition of citrulline- and arginine-containing filaggrin, vimentin and collagen peptide epitopes were tested by Multipin ELISA system, by indirect ELISA and by a peptide-specific microarray. B cells were purified from blood by negative selection; antibody-producing cells were enumerated by ELISPOT assay. The panel composed of citrulline-peptide epitopes of filaggrin, collagen and vimentin was recognized by RA sera with a sensitivity and specificity comparable with the currently used tests. Moreover, the combined citrulline-peptide panel including the new short epitope peptide of filaggrin, fil311-315, also identified nearly one-third of RA cases that were negative for antibodies against cyclic citrullinated peptides, mutated citrullinated vimentin or for rheumatoid factor. The results with the peptide-specific microarray have shown that although most ACPAs recognizing the four citrulline peptides are IgG, some of them specifically recognizing citrulline-containing filaggrin peptides (fil311-315 and fil306-326) are IgM, and so may be produced either by newly formed activated B cells or by unswitched B memory cells. Furthermore, the citrulline-peptides of filaggrin and vimentin detect ACPA-producing cells, and so could also be applied to study the B cells of RA patients.


Asunto(s)
Artritis Reumatoide/inmunología , Autoanticuerpos/inmunología , Linfocitos B/inmunología , Citrulina/inmunología , Epítopos , Adulto , Anciano , Secuencia de Aminoácidos , Colágeno/inmunología , Reacciones Cruzadas , Estudios Transversales , Ensayo de Inmunoadsorción Enzimática , Femenino , Proteínas Filagrina , Humanos , Proteínas de Filamentos Intermediarios/inmunología , Masculino , Persona de Mediana Edad , Datos de Secuencia Molecular , Vimentina/inmunología
14.
Nat Commun ; 15(1): 6338, 2024 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-39068149

RESUMEN

The continued evolution of SARS-CoV-2 underscores the need to understand qualitative aspects of the humoral immune response elicited by spike immunization. Here, we combine monoclonal antibody (mAb) isolation with deep B cell receptor (BCR) repertoire sequencing of rhesus macaques immunized with prefusion-stabilized spike glycoprotein. Longitudinal tracing of spike-sorted B cell lineages in multiple immune compartments demonstrates increasing somatic hypermutation and broad dissemination of vaccine-elicited B cells in draining and non-draining lymphoid compartments, including the bone marrow, spleen and, most notably, periaortic lymph nodes. Phylogenetic analysis of spike-specific monoclonal antibody lineages identified through deep repertoire sequencing delineates extensive intra-clonal diversification that shaped neutralizing activity. Structural analysis of the spike in complex with a broadly neutralizing mAb provides a molecular basis for the observed differences in neutralization breadth between clonally related antibodies. Our findings highlight that immunization leads to extensive intra-clonal B cell evolution where members of the same lineage can both retain the original epitope specificity and evolve to recognize additional spike variants not previously encountered.


Asunto(s)
Anticuerpos Monoclonales , Anticuerpos Neutralizantes , Anticuerpos Antivirales , Linfocitos B , Macaca mulatta , Filogenia , SARS-CoV-2 , Glicoproteína de la Espiga del Coronavirus , Animales , Glicoproteína de la Espiga del Coronavirus/inmunología , Glicoproteína de la Espiga del Coronavirus/genética , Anticuerpos Neutralizantes/inmunología , SARS-CoV-2/inmunología , SARS-CoV-2/genética , Linfocitos B/inmunología , Anticuerpos Antivirales/inmunología , Anticuerpos Monoclonales/inmunología , Epítopos/inmunología , COVID-19/inmunología , COVID-19/virología , Humanos , Vacunas contra la COVID-19/inmunología , Receptores de Antígenos de Linfocitos B/inmunología , Receptores de Antígenos de Linfocitos B/genética , Hipermutación Somática de Inmunoglobulina , Inmunización
15.
J Virol ; 86(8): 4701-7, 2012 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-22345482

RESUMEN

We report that type I interferons (IFNs) upregulate latent membrane protein 1 (LMP-1) expression by direct activation of the ED-L1 promoter in several Epstein-Barr virus (EBV)-carrying Burkitt's lymphoma lines. In EBV-infected primary B cells, IFN-α transiently upregulates LMP-1 mRNA, but not protein levels, followed by downregulation of both, suggesting a novel antiproliferative mechanism of type I IFNs. Furthermore, our results may explain the expression of LMP-1 in memory B cells of systemic lupus erythematosus patients.


Asunto(s)
Linfocitos B/metabolismo , Herpesvirus Humano 4/genética , Interferón Tipo I/metabolismo , Proteínas de la Matriz Viral/genética , Linfocitos B/efectos de los fármacos , Linfocitos B/virología , Línea Celular , Regulación Viral de la Expresión Génica/efectos de los fármacos , Herpesvirus Humano 4/inmunología , Humanos , Interferón Tipo I/farmacología , Datos de Secuencia Molecular , Regiones Promotoras Genéticas , Transducción de Señal/efectos de los fármacos , Transcripción Genética , Proteínas de la Matriz Viral/metabolismo , Latencia del Virus
16.
Cells ; 12(9)2023 04 24.
Artículo en Inglés | MEDLINE | ID: mdl-37174629

RESUMEN

Lipopolysaccharide (LPS) stimulates dual receptor signaling by bridging the B cell receptor and Toll-like receptor 4 (BCR/TLR4). B cells from IκBNS-deficient bumble mice treated with LPS display reduced proliferative capacity and impaired plasma cell differentiation. To improve our understanding of the regulatory role of IκBNS in B cell activation and differentiation, we investigated the BCR and TLR4 signaling pathways separately by using dimeric anti-IgM Fab (F(ab')2) or lipid A, respectively. IκBNS-deficient B cells exhibited reduced survival and defective proliferative capacity in response to lipid A compared to B cells from wildtype (wt) control mice. In contrast, anti-IgM stimulation of bumble B cells resulted in enhanced viability and increased differentiation into CD138+ cells compared to control B cells. Anti-IgM-stimulated IκBNS-deficient B cells also showed enhanced cycle progression with increased levels of c-Myc and cyclin D2, and augmented levels of pCD79a, pSyk, and pERK compared to control B cells. These results suggest that IκBNS acts as a negative regulator of BCR signaling and a positive regulator of TLR4 signaling in mouse B cells.


Asunto(s)
Lipopolisacáridos , Receptor Toll-Like 4 , Animales , Ratones , Lipopolisacáridos/farmacología , Receptor Toll-Like 4/metabolismo , Lípido A , Linfocitos B/metabolismo , Receptores de Antígenos de Linfocitos B
17.
JCI Insight ; 8(17)2023 09 08.
Artículo en Inglés | MEDLINE | ID: mdl-37681412

RESUMEN

Pathogenic mutations in mitochondrial (mt) tRNA genes that compromise oxidative phosphorylation (OXPHOS) exhibit heteroplasmy and cause a range of multisyndromic conditions. Although mitochondrial disease patients are known to suffer from abnormal immune responses, how heteroplasmic mtDNA mutations affect the immune system at the molecular level is largely unknown. Here, in mice carrying pathogenic C5024T in mt-tRNAAla and in patients with mitochondrial encephalomyopathy, lactic acidosis, stroke-like episodes (MELAS) syndrome carrying A3243G in mt-tRNALeu, we found memory T and B cells to have lower pathogenic mtDNA mutation burdens than their antigen-inexperienced naive counterparts, including after vaccination. Pathogenic burden reduction was less pronounced in myeloid compared with lymphoid lineages, despite C5024T compromising macrophage OXPHOS capacity. Rapid dilution of the C5024T mutation in T and B cell cultures could be induced by antigen receptor-triggered proliferation and was accelerated by metabolic stress conditions. Furthermore, we found C5024T to dysregulate CD8+ T cell metabolic remodeling and IFN-γ production after activation. Together, our data illustrate that the generation of memory lymphocytes shapes the mtDNA landscape, wherein pathogenic variants dysregulate the immune response.


Asunto(s)
Acidosis Láctica , Receptores de Antígenos , Animales , Ratones , Mutación , ADN Mitocondrial/genética , ARN de Transferencia/genética
18.
Cytokine ; 57(3): 360-71, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22204827

RESUMEN

Type I interferons (IFN) exert multiple effects on both the innate and adaptive immune system in addition to their antiviral and antiproliferative activities. Little is known, however about the direct effects of type I IFNs on germinal center (GC) B cells, the central components of adaptive B cell responses. We used Burkitt's lymphoma (BL) lines, as a model system of normal human GC B cells, to examine the effect of type I IFNs on the expression of BCL-6, the major regulator of the GC reaction. We show that type I IFNs, but not IFNγ, IL-2 and TNFα rapidly down-regulate BCL-6 protein and mRNA expression, in cell lines derived from endemic, but not from sporadic BL. IFNα-induced down-regulation is specific for BCL-6, independent of Epstein-Barr virus and is not accompanied by IRF-4 up-regulation. IFNα-induced BCL-6 mRNA down-regulation does not require de novo protein synthesis and is specifically inhibited by piceatannol. The proteasome inhibitor MG132 non-specifically prevents, while inhibitors of alternate type I IFN signaling pathways do not inhibit IFNα-induced BCL-6 protein downregulation. We validate our results with showing that IFNα rapidly down-regulates BCL-6 mRNA in purified mouse normal GC B cells. Our results identify type I IFNs as the first group of cytokines that can down-regulate BCL-6 expression directly in GC B cells.


Asunto(s)
Linfocitos B/metabolismo , Linfoma de Burkitt/patología , Proteínas de Unión al ADN/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Centro Germinal/citología , Interferón-alfa/farmacología , Proteínas Adaptadoras Transductoras de Señales , Animales , Linfocitos B/efectos de los fármacos , Linfoma de Burkitt/inmunología , Linfoma de Burkitt/virología , Línea Celular Transformada , Proteínas de Unión al ADN/genética , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Herpesvirus Humano 4/efectos de los fármacos , Herpesvirus Humano 4/inmunología , Humanos , Factores Reguladores del Interferón/metabolismo , Interferón gamma/farmacología , Interleucina-2/farmacología , Cinética , Leupeptinas/farmacología , Ratones , Biosíntesis de Proteínas/efectos de los fármacos , Proteínas Proto-Oncogénicas c-bcl-6 , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas de Unión al ARN , Transducción de Señal/efectos de los fármacos , Estilbenos/farmacología , Factores de Transcripción/metabolismo , Factor de Necrosis Tumoral alfa/farmacología
19.
Front Immunol ; 13: 1000755, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36341341

RESUMEN

Mice lacking the atypical inhibitory kappa B (IκB) protein, IκBNS, a regulator of the NF-κB pathway encoded by the nfkbid gene, display impaired antibody responses to both T cell-independent (TI) and T cell-dependent (TD) antigens. To better understand the basis of these defects, we crossed mice carrying floxed nfkbid alleles with mice expressing Cre under the transcriptional control of the Cd79a gene to create mice that lacked IκBNS expression only in B cells. Analyses of these conditional knock-out mice revealed intact CD4+ and CD8+ T cell populations, including preserved frequencies of FoxP3+ regulatory T cells, which are known to be reduced in IκBNS knock-out mice. Like IκBNS knock-out mice, mice with conditional IκBNS ablation in B cells displayed defective IgM responses to TI antigens and a severe reduction in peritoneal B-1a cells. However, in contrast to mice lacking IκBNS altogether, the conditional IκBNS knock-out mice responded well to TD antigens compared to the control mice, with potent IgG responses following immunization with the viral antigen, rSFV-ßGal or the widely used hapten-protein model antigen, NP-CGG. Furthermore, B cell intrinsic IκBNS expression was dispensable for germinal center (GC) formation and T follicular helper cell responses to NP-CGG immunization. The results presented here suggest that the defect in antibody responses to TD antigens observed in IκBNS knock-out mice results from a B cell extrinsic defect.


Asunto(s)
Antígenos , Linfocitos B , Ratones , Animales , Diferenciación Celular , Ratones Noqueados , FN-kappa B/metabolismo , Inmunoglobulina G
20.
Cell Mol Life Sci ; 67(10): 1661-74, 2010 May.
Artículo en Inglés | MEDLINE | ID: mdl-20140748

RESUMEN

Estrogen plays a critical regulatory role in the development and maintenance of immunity. Its role in the regulation of antibody synthesis in vivo is still not completely clear. Here, we have compared the effect of estrogen on T cell-dependent (TD) and T cell-independent type 2 (TI-2) antibody responses. The results provide the first evidence that estrogen enhances the TD but not the TI-2 response. Ovariectomy significantly decreased, while estrogen re-administration increased the number of hapten-specific IgM- and IgG-producing cells in response to TD antigen. In vitro experiments also show that estrogen may have a direct impact on B and T cells by inducing rapid signaling events, such as Erk and AKT phosphorylation, cell-specific Ca(2+) signal, and NFkappaB activation. These non-transcriptional effects are mediated by classical estrogen receptors and partly by an as yet unidentified plasma membrane estrogen receptor. Such receptor- mediated rapid signals may modulate the in vivo T cell-dependent immune response.


Asunto(s)
Estradiol/farmacología , Inmunidad/efectos de los fármacos , Linfocitos T/efectos de los fármacos , Linfocitos T/inmunología , Animales , Formación de Anticuerpos/efectos de los fármacos , Linfocitos B/citología , Linfocitos B/efectos de los fármacos , Linfocitos B/enzimología , Linfocitos B/inmunología , Señalización del Calcio/efectos de los fármacos , Núcleo Celular/efectos de los fármacos , Núcleo Celular/metabolismo , Activación Enzimática/efectos de los fármacos , Quinasas MAP Reguladas por Señal Extracelular/metabolismo , Femenino , Interferón gamma/genética , Ratones , Ratones Endogámicos C57BL , FN-kappa B/metabolismo , Ovariectomía , Fosforilación/efectos de los fármacos , Transporte de Proteínas/efectos de los fármacos , Proteínas Proto-Oncogénicas c-akt/metabolismo , Receptores de Estrógenos/metabolismo , Linfocitos T/citología , Linfocitos T/enzimología , Transcripción Genética/efectos de los fármacos
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