RESUMO
INTRODUCTION: Post-traumatic stress disorder occurs in parents of infants with CHD, contributing to psychological distress with detrimental effects on family functioning and well-being. We sought to determine the prevalence and factors associated with post-traumatic stress disorder symptoms in parents whose infants underwent staged palliation for single ventricle heart disease. MATERIALS AND METHODS: A large longitudinal multi-centre cohort study evaluated 215 mothers and fathers for symptoms of post-traumatic stress disorder at three timepoints, including post-Norwood, post-Stage II, and a final study timepoint when the child reached approximately 16 months of age, using the self-report questionnaire Impact of Event Scale - Revised. RESULTS: The prevalence of probable post-traumatic stress disorder post-Norwood surgery was 50% of mothers and 39% of fathers, decreasing to 27% of mothers and 24% of fathers by final follow-up. Intrusive symptoms such as flashbacks and nightmares and hyperarousal symptoms such as poor concentration, irritability, and sudden physical symptoms of racing heart and difficulty breathing were particularly elevated in parents. Higher levels of anxiety, reduced coping, and decreased satisfaction with parenting were significantly associated with symptoms of post-traumatic stress disorder in parents. Demographic and clinical variables such as parent education, pre-natal diagnosis, medical complications, and length of hospital stay(s) were not significantly associated with symptoms of post-traumatic stress disorder. DISCUSSION: Parents whose infants underwent staged palliation for single ventricle heart disease often reported symptoms of post-traumatic stress disorder. Symptoms persisted over time and routine screening might help identify parents at-risk and prompt referral to appropriate supports.
Assuntos
Cardiopatias , Transtornos de Estresse Pós-Traumáticos , Criança , Feminino , Lactente , Humanos , Transtornos de Estresse Pós-Traumáticos/epidemiologia , Transtornos de Estresse Pós-Traumáticos/etiologia , Prevalência , Estudos de Coortes , Pais/psicologia , Cardiopatias/complicações , Estresse Psicológico/psicologiaRESUMO
The roles distinct B cell subsets play in clonal expansion, isotype switching, and memory B cell differentiation in response to T cell-independent type 2 Ags (TI-2 Ags) has been understudied. Using sorted B cells from VHB1-8 knock-in mice, we evaluated B-1b, marginal zone, and follicular B cell responses to the TI-2 Ag, NP-Ficoll. All subsets extensively divided in response to NP-Ficoll. Nonetheless, B-1b cells exhibited significantly increased IgG switching and differentiation into Ab-secreting cells (ASC)-a finding that coincided with increased AgR signaling capacity and Blimp1 expression by B-1b cells. All subsets formed memory cells and expressed markers previously identified for T cell-dependent memory B cells, including CD80, PDL2, and CD73, although B-1b cells generated the greatest number of memory cells with higher frequencies of IgG- and CD80-expressing cells. Despite memory formation, secondary immunization 4 wk after primary immunization did not increase NP-specific IgG. However, boosting occurred in B-1b cell-recipient mice when IgG levels declined. CD80+ memory B-1b cells divided, class switched, and differentiated into ASC in response to Ag in vivo, but this was inhibited in the presence of NP-specific IgG. Furthermore, CD80 blockade significantly increased memory B-1b cell division and differentiation to ASC upon Ag restimulation. Collectively, these findings demonstrate B-1b, marginal zone B, and follicular B subsets significantly contribute to the TI-2 Ag-specific memory B cell pool. In particular, we show B-1b cells generate a functional CD80-regulated memory population that can be stimulated to divide and differentiate into ASC upon Ag re-encounter when Ag-specific IgG levels decline.
Assuntos
Subpopulações de Linfócitos B/imunologia , Memória Imunológica/imunologia , Linfócitos T/imunologia , Animais , Antígenos T-Independentes/imunologia , Antígeno B7-1/imunologia , Diferenciação Celular/imunologia , Divisão Celular/imunologia , Switching de Imunoglobulina/imunologia , Imunoglobulina G/imunologia , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Transdução de Sinais/imunologiaRESUMO
Metastatic cancer involving spread to the peritoneal cavity is referred to as peritoneal carcinomatosis and has a very poor prognosis. Our previous studies demonstrated a toll-like receptor 4 (TLR4) and C-type lectin receptor (CLR; Mincle/MCL) agonist pairing of monophosphoryl lipid A (MPL) and trehalose-6,6'-dicorynomycolate (TDCM) effectively inhibits peritoneal tumor growth and ascites development through a mechanism dependent upon B1a cell-produced natural IgM, complement, and phagocytes. In the current study, we investigated the requirement for TLR4 and Fc receptor common γ chain (FcRγ), required for Mincle/MCL signaling, in the MPL/TDCM-elicited response. MPL/TDCM significantly increased macrophages and Ly6Chi monocytes in the peritoneal cavity of both TLR4-/- and FcRγ-/- mice, suggesting redundancy in the signals required for monocyte/macrophage recruitment. However, B1 cell activation, antibody secreting cell differentiation, and tumor-reactive IgM production were defective in TLR4-/-, but not FcRγ-/- mice. TRIF was required for production of IgM reactive against tumor- and mucin-related antigens, but not phosphorylcholine, whereas TLR4 was required for production of both types of reactivities. Consistent with this, B1 cells lacking TLR4 or TRIF did not proliferate or differentiate into tumor-reactive IgM-producing cells in vitro and did not reconstitute MPL/TDCM-dependent protection against peritoneal carcinomatosis in CD19-/- mice. Our results indicate a TLR4/TRIF-dependent pathway is required by B1 cells for MPL/TDCM-elicited production of protective tumor-reactive natural IgM. The dependency on TRIF signaling for tumor-reactive, but not phosphorylcholine-reactive, IgM production reveals unexpected heterogeneity in TLR4-dependent regulation of natural IgM production, thereby highlighting important differences to consider when designing vaccines or therapies targeting these specificities.
Assuntos
Proteínas Adaptadoras de Transporte Vesicular/fisiologia , Subpopulações de Linfócitos B/imunologia , Fatores Corda/administração & dosagem , Imunoglobulina M/imunologia , Lipídeo A/análogos & derivados , Neoplasias Peritoneais/imunologia , Receptor 4 Toll-Like/fisiologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Subpopulações de Linfócitos B/efeitos dos fármacos , Lipídeo A/administração & dosagem , Macrófagos/efeitos dos fármacos , Macrófagos/imunologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 88 de Diferenciação Mieloide/fisiologia , Neoplasias Peritoneais/metabolismo , Neoplasias Peritoneais/patologiaRESUMO
Metastatic cancer involving spread to the peritoneal cavity is referred to as peritoneal carcinomatosis and has a very poor prognosis. Our previous study demonstrated a Toll-like receptor and C-type lectin receptor agonist pairing of monophosphoryl lipid A (MPL) and trehalose-6,6'-dicorynomycolate (TDCM) effectively inhibits tumor growth and ascites development following TA3-Ha and EL4 challenge through a mechanism dependent on B-1a cell-produced natural IgM and complement. In this study, we investigated additional players in the MPL/TDCM-elicited response. MPL/TDCM treatment rapidly increased type I IFN levels in the peritoneal cavity along with myeloid cell numbers, including macrophages and Ly6Chi monocytes. Type I IFN receptor (IFNAR1-/-) mice produced tumor-reactive IgM following MPL/TDCM treatment, but failed to recruit Ly6C+ monocytes and were not afforded protection during tumor challenges. Clodronate liposome depletion of phagocytic cells, as well as targeted depletion of Ly6C+ cells, also ablated MPL/TDCM-induced protection. Cytotoxic mediators known to be produced by these cells were required for effects. TNFα was required for effective TA3-Ha killing and nitric oxide was required for EL4 killing. Collectively, these data reveal a model whereby MPL/TDCM-elicited antitumor effects strongly depend on innate cell responses, with B-1a cell-produced tumor-reactive IgM and complement pairing with myeloid cell-produced cytotoxic mediators to effectively eradicate tumors in the peritoneal cavity.
Assuntos
Antígenos Ly/metabolismo , Fatores Corda/farmacologia , Interferon Tipo I/metabolismo , Lectinas Tipo C/agonistas , Lipídeo A/análogos & derivados , Neoplasias Peritoneais/tratamento farmacológico , Receptores Toll-Like/agonistas , Adjuvantes Imunológicos/farmacologia , Animais , Apoptose , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Proliferação de Células , Quimioterapia Combinada , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Lipídeo A/farmacologia , Linfoma/tratamento farmacológico , Linfoma/metabolismo , Linfoma/patologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Macrófagos/patologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Neoplasias Peritoneais/metabolismo , Neoplasias Peritoneais/secundário , Fagócitos , Receptor de Interferon alfa e beta/fisiologia , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
P53-binding protein 1 (53BP1) mediates DNA repair pathway choice and promotes checkpoint activation. Chromatin marks induced by DNA double-strand breaks and recognized by 53BP1 enable focal accumulation of this multifunctional repair factor at damaged chromatin. Here, we unveil an additional level of regulation of 53BP1 outside repair foci. 53BP1 movements are constrained throughout the nucleoplasm and increase in response to DNA damage. 53BP1 interacts with the structural protein NuMA, which controls 53BP1 diffusion. This interaction, and colocalization between the two proteins in vitro and in breast tissues, is reduced after DNA damage. In cell lines and breast carcinoma NuMA prevents 53BP1 accumulation at DNA breaks, and high NuMA expression predicts better patient outcomes. Manipulating NuMA expression alters PARP inhibitor sensitivity of BRCA1-null cells, end-joining activity, and immunoglobulin class switching that rely on 53BP1. We propose a mechanism involving the sequestration of 53BP1 by NuMA in the absence of DNA damage. Such a mechanism may have evolved to disable repair functions and may be a decisive factor for tumor responses to genotoxic treatments.
Assuntos
Antígenos Nucleares/fisiologia , Quebras de DNA de Cadeia Dupla , Reparo do DNA/genética , Proteínas Associadas à Matriz Nuclear/fisiologia , Proteína 1 de Ligação à Proteína Supressora de Tumor p53/metabolismo , Proteínas de Ciclo Celular , Células Cultivadas , Reparo do DNA por Junção de Extremidades/genética , Regulação para Baixo , Feminino , Células HEK293 , Humanos , Ligação ProteicaRESUMO
Metastatic cancer involving spread to the peritoneal cavity is referred to as peritoneal carcinomatosis and has a very poor prognosis. Activating the antitumor immune response in the characteristically immune-suppressive peritoneal environment presents a potential strategy to treat this disease. In this study, we show that a toll-like receptor (TLR) and C-type lectin receptor (CLR) agonist pairing of monophosphoryl lipid A (MPL) and trehalose-6,6'-dicorynomycolate (TDCM) effectively inhibits tumor growth and ascites development in a mouse model of aggressive mammary cancer-induced peritoneal carcinomatosis. MPL/TDCM treatment similarly inhibited peritoneal EL4 tumor growth and ascites development. These effects were not observed in mice lacking B cells or mice lacking CD19, which are deficient in B-1a cells, an innate-like B-cell population enriched in the peritoneal cavity. Remarkably, adoptive transfer of B-1a cells, but not splenic B cells from WT mice, restored MPL/TDCM-induced protection in mice with B-cell defects. Treatment induced B-1 cells to rapidly produce high levels of natural IgM reactive against tumor-associated carbohydrate antigens. Consistent with this, we found significant deposition of IgM and C3 on peritoneal tumor cells as early as 5 days post-treatment. Mice unable to secrete IgM or complement component C4 were not protected by MPL/TDCM treatment, indicating tumor killing was mediated by activation of the classical complement pathway. Collectively, our findings reveal an unsuspected role for B-1 cell-produced natural IgM in providing protection against tumor growth in the peritoneal cavity, thereby highlighting potential opportunities to develop novel therapeutic strategies for the prevention and treatment of peritoneal metastases. SIGNIFICANCE: This work identifies a critical antitumor role for innate-like B cells localized within the peritoneal cavity and demonstrates a novel strategy to activate their tumor-killing potential.See related commentary by Tripodo, p. 5.
Assuntos
Subpopulações de Linfócitos B/imunologia , Imunidade Inata/imunologia , Imunoglobulina M/imunologia , Ativação Linfocitária/imunologia , Neoplasias Mamárias Animais/imunologia , Cavidade Peritoneal/patologia , Neoplasias Peritoneais/imunologia , Animais , Subpopulações de Linfócitos B/efeitos dos fármacos , Subpopulações de Linfócitos B/metabolismo , Subpopulações de Linfócitos B/patologia , Fatores Corda/farmacologia , Feminino , Imunidade Inata/efeitos dos fármacos , Imunoglobulina M/efeitos dos fármacos , Lectinas Tipo C/agonistas , Lipídeo A/análogos & derivados , Lipídeo A/farmacologia , Ativação Linfocitária/efeitos dos fármacos , Masculino , Neoplasias Mamárias Animais/tratamento farmacológico , Neoplasias Mamárias Animais/metabolismo , Neoplasias Mamárias Animais/patologia , Camundongos , Camundongos Endogâmicos A , Camundongos Endogâmicos C57BL , Neoplasias Peritoneais/tratamento farmacológico , Neoplasias Peritoneais/metabolismo , Neoplasias Peritoneais/secundário , Receptores Toll-Like/agonistasRESUMO
B-1 cells produce natural Abs which provide an integral first line of defense against pathogens while also performing important homeostatic housekeeping functions. In this study, we demonstrate that programmed cell death 1 ligand 2 (PD-L2) regulates the production of natural Abs against phosphorylcholine (PC). Naive PD-L2-deficient (PD-L2-/-) mice produced significantly more PC-reactive IgM and IgA. This afforded PD-L2-/- mice with selectively enhanced protection against PC-expressing nontypeable Haemophilus influenzae, but not PC-negative nontypeable Haemophilus influenzae, relative to wild-type mice. PD-L2-/- mice had significantly increased PC-specific CD138+ splenic plasmablasts bearing a B-1a phenotype, and produced PC-reactive Abs largely of the T15 Id. Importantly, PC-reactive B-1 cells expressed PD-L2 and irradiated chimeras demonstrated that B cell-intrinsic PD-L2 expression regulated PC-specific Ab production. In addition to increased PC-specific IgM, naive PD-L2-/- mice and irradiated chimeras reconstituted with PD-L2-/- B cells had significantly higher levels of IL-5, a potent stimulator of B-1 cell Ab production. PD-L2 mAb blockade of wild-type B-1 cells in culture significantly increased CD138 and Blimp1 expression and PC-specific IgM, but did not affect proliferation. PD-L2 mAb blockade significantly increased IL-5+ T cells in culture. Both IL-5 neutralization and STAT5 inhibition blunted the effects of PD-L2 mAb blockade on B-1 cells. Thus, B-1 cell-intrinsic PD-L2 expression inhibits IL-5 production by T cells and thereby limits natural Ab production by B-1 cells. These findings have broad implications for the development of therapeutic strategies aimed at altering natural Ab levels critical for protection against infectious disease, autoimmunity, allergy, cancer, and atherosclerosis.
Assuntos
Formação de Anticorpos , Linfócitos B/imunologia , Imunoglobulina M/metabolismo , Fosforilcolina/imunologia , Proteína 2 Ligante de Morte Celular Programada 1/metabolismo , Linfócitos T/imunologia , Animais , Anticorpos Bloqueadores/farmacologia , Diferenciação Celular , Proliferação de Células , Células Cultivadas , Homeostase , Imunidade Inata , Interleucina-5/metabolismo , Ativação Linfocitária , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fator 1 de Ligação ao Domínio I Regulador Positivo , Proteína 2 Ligante de Morte Celular Programada 1/imunologia , Sindecana-1/genética , Sindecana-1/metabolismo , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismoRESUMO
Tn is a carbohydrate antigen uniquely exposed on tumor mucins and, thus, an ideal target for immunotherapy. However, it has been difficult to elicit protective antibody responses against Tn antigen and other tumor-associated carbohydrate antigens. Our study demonstrates this can be attributed to PD-1 immuno-inhibition. Our data show a major role for PD-1 in suppressing mucin- and Tn-specific B-cell activation, expansion, and antibody production important for protection against Tn-bearing tumor cells. These Tn/mucin-specific B cells belong to the innate-like B-1b cell subset typically responsible for T cell-independent antibody responses. Interestingly, PD-1-mediated regulation is B cell-intrinsic and CD4+ cells play a key role in supporting Tn/mucin-specific B-cell antibody production in the context of PD-1 deficiency. Mucin-reactive antibodies produced in the absence of PD-1 inhibition largely belong to the IgM subclass and elicit potent antitumor effects via a complement-dependent mechanism. The identification of this role for PD-1 in regulating B cell-dependent antitumor immunity to Tn antigen highlights an opportunity to develop new therapeutic strategies targeting tumor-associated carbohydrate antigens. Cancer Immunol Res; 4(12); 1027-37. ©2016 AACR.
Assuntos
Antígenos Glicosídicos Associados a Tumores/imunologia , Neoplasias/imunologia , Receptor de Morte Celular Programada 1/imunologia , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Imunização , Imunoglobulina G/imunologia , Imunoglobulina M/imunologia , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mucinas/imunologia , Neoplasias/terapia , Receptor de Morte Celular Programada 1/genéticaRESUMO
A clinician-driven home monitoring program can improve interstage outcomes in single-ventricle patients. Sociodemographic factors have been independently associated with mortality in interstage patients. We hypothesized that even in a population with high-risk sociodemographic characteristics, a home monitoring program is effective in reducing interstage mortality. We defined interstage period as the time period between discharge following Norwood palliation and second-stage surgery. We reviewed the charts of patients for the three-year period before (group 1) and after (group 2) implementation of the home monitoring program. Clinical variables around Norwood palliation, during the interstage period, and at the time of second-stage surgery were analyzed. There were 74 patients in group 1 and 52 in group 2. 59 % patients were Hispanic, and 84 % lived in neighborhoods where over 5 % families lived below poverty line. There was no significant difference in pre-Norwood variables, Norwood discharge variables, age at second surgery, or outcomes at second surgery. There were more Sano shunts performed at the Norwood procedure as the source of pulmonary blood flow in group 2 (p value <0.05). There were more unplanned hospital admissions and percutaneous re-interventions in group 2. Patients in group 2 whose admission criteria included desaturation had a 45 % likelihood of having an unplanned re-intervention. Group 2 noted an 80 % relative reduction in interstage mortality (p < 0.01). In a multiple regression analysis, after accounting for ethnicity, socio-economic status, and source of pulmonary blood flow, enrollment in a home monitoring program independently predicted improved interstage survival (p < 0.01). A clinician-driven home monitoring program reduces interstage mortality even when the majority of patients has high-risk sociodemographic characteristics.
Assuntos
Ventrículos do Coração , Humanos , Síndrome do Coração Esquerdo Hipoplásico , Procedimentos de Norwood , Cuidados Paliativos , Alta do Paciente , Estudos Retrospectivos , Fatores de Risco , Resultado do TratamentoRESUMO
For successful carbohydrate based anti-cancer vaccines, it is critical that B cells are activated to secret antibodies targeting the tumor associated carbohydrate antigens (TACAs). Despite the availability of many TACA based constructs, systematic understanding of the effects of structural features on anti-glycan antibody responses is lacking. In this study, a series of defined synthetic glyco-polymers bearing a representative TACA, i.e., the Thomsen-nouveau (Tn) antigen, have been prepared to probe the induction of early B cell activation and antibody production via a T cell independent mechanism. Valency and density of the antigen in the polymers turned out to be critical. An average of greater than 6 Tn per chain was needed to induce antibody production. Glycopolymers with 40 antigens per chain and backbone molecular weight of 450 kDa gave the strongest stimulation to B cells in vitro, which correlated well with its in vivo activity. Deviations from the desired valency and density led to decreased antibody production or even antigen specific B cell non-responsiveness. These findings provide important insights on how to modulate anti-TACA immune responses facilitating the development of TACA based anti-cancer vaccines using glycopolymers.
Assuntos
Formação de Anticorpos , Antígenos Glicosídicos Associados a Tumores/imunologia , Linfócitos B/imunologia , Vacinas Anticâncer/imunologia , Carboidratos/imunologia , Animais , Antígenos Glicosídicos Associados a Tumores/química , Vacinas Anticâncer/química , Carboidratos/química , Células Cultivadas , Feminino , Camundongos Endogâmicos C57BL , Neoplasias/imunologia , Neoplasias/prevenção & controleRESUMO
B-1 cells comprise subpopulations of B lymphocytes in mice that display developmental, phenotypic, and functional characteristics that are distinct from those of conventional B cell populations (B-2 cells). Despite the known importance of murine B-1a (CD5(+) ) and B-1b (CD5(-) ) cells in the production of natural antibodies and rapid antigen-specific humoral responses to infection, evidence for B-1 cells in primates, including humans, is very limited. Identifying these cells in humans proves challenging given the limited number of cells that can be obtained from sites expected to harbor increased frequencies of these cells (i.e., peritoneal and pleural cavities) and the need to perform functional analyses on these cells, which, in the case of B-1b cells, must be carried out in vivo. My laboratory has used cynomolgus macaques and African green monkeys to bypass these limitations and to identify and extensively analyze primate B cell populations with the phenotypic and functional characteristics of mouse B-1a and B-1b cells. Our results reveal striking similarities between primate and murine B-1 cells, including a conserved functional role for primate B-1b-like cells in immunity to T cell-independent type 2 antigens.
Assuntos
Subpopulações de Linfócitos B/fisiologia , Camundongos Endogâmicos C57BL/fisiologia , Primatas/fisiologia , Animais , Chlorocebus aethiops , Humanos , Macaca fascicularis , Camundongos , Especificidade da EspécieRESUMO
The efficacy of different vaccines in protecting elderly individuals against Streptococcus pneumoniae infections is not clear. In the current study, aged mice (22-25 months old) exhibited significantly increased susceptibility to respiratory infection with serotype 3 S. pneumoniae relative to younger adult mice, regardless of whether mice were naive or immunized with native pneumococcal polysaccharide (PPS; Pneumovax23) or protein-PPS conjugate (Prevnar-13) vaccines. Nonetheless, Pneumovax-immunized aged mice developed limited bacteremia following respiratory challenge and exhibited significantly increased survival following systemic challenge relative to Prevnar-immune aged mice and young mice that had received either vaccine. This was explained by >10-fold increases in PPS-specific immunoglobulin G (IgG) levels in Pneumovax-immunized aged mice relative to other groups. Remarkably, PPS3-specific B-cell expansion, IgG switching, plasmablast differentiation, and spleen and bone marrow antibody-secreting cell frequencies were 10-fold higher in aged mice following Pneumovax immunization relative to young mice, due to significantly increased B-1b cell participation. In summary, this study highlights (1) the need to devise strategies to enhance respiratory immunity in aged populations, (2) the diverse responses young and aged populations generate to Pneumovax vs Prevnar vaccines, and (3) the potential value of exploiting B-1b cell responses in aged individuals for increased vaccine efficacy.
Assuntos
Subpopulações de Linfócitos B/imunologia , Vacinas Pneumocócicas/imunologia , Pneumonia Pneumocócica/imunologia , Fatores Etários , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Suscetibilidade a Doenças/imunologia , Imunidade Humoral/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Vacinas Pneumocócicas/farmacologia , Polissacarídeos Bacterianos/imunologiaRESUMO
Ab responses to T cell-independent type 2 (TI-2) Ags, such as bacterial capsular polysaccharides, are critical for host defense. In mice, B-1b cells expressing a CD11b(+)FSC(hi)CD21(lo/-)CD19(hi) phenotype play a key role in producing Abs against TI-2 Ags. In primates, a distinct IgM(+)CD27(+) "memory" B cell population is thought to generate TI-2 Ab responses, and evidence for a B-1b-like cell population participating in these responses is lacking. In this article, we demonstrate that nonhuman primates (NHPs; African green monkeys and cynomolgus macaques) harbor serosal B cells expressing a CD11b(+)FSC(hi)CD21(lo/-)CD80(+/-)CD19(hi) phenotype, constitutively active Stat3, and increased reactivity with phosphorylcholine, similar to murine peritoneal B-1a and B-1b cell populations. Like what is observed for murine B-1b cells, NHP CD11b(+)FSC(hi)CD21(lo/-)CD19(hi) B cells dominate the Ag-specific B cell response and Ab production against the TI-2 Ag trinitrophenyl-Ficoll. Although Ag-specific IgM(+) B cells expressing CD27 were not detected prior to immunization, Ag-specific CD11b(+)CD19(hi) B cells expressed and maintained an IgM(+)IgD(lo)CD27(+)CD80(+) phenotype following immunization. Thus, the murine and NHP B cell populations responding to trinitrophenyl-Ficoll are highly similar, with the main exception being that Ag-specific NHP B-1-like cells express CD27 following TI-2 Ag encounter. Therefore, murine B-1b and primate IgM(+)CD27(+) "memory" B cell subsets proposed to produce TI-2 Ab responses may be highly related, if not identical. Overall, these data not only support that B-1-like cells are present in NHPs but also provide evidence that these cells perform the same functions attributed to murine B-1b cells.
Assuntos
Antígenos/imunologia , Subpopulações de Linfócitos B/imunologia , Epitopos/imunologia , Linfócitos T/imunologia , Animais , Formação de Anticorpos/imunologia , Subpopulações de Linfócitos B/metabolismo , Células Cultivadas , Chlorocebus aethiops , Ficoll/imunologia , Macaca fascicularis , Masculino , Camundongos , Baço/imunologia , Baço/metabolismo , Linfócitos T/metabolismo , Trinitrobenzenos/imunologia , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/metabolismoRESUMO
Malignant B cells responding to external stimuli are likely to gain a growth advantage in vivo. These cells may therefore maintain surface CD19 expression to amplify transmembrane signals and promote their expansion and survival. To determine whether CD19 expression influences this process, Eµ-Myc transgenic (c-Myc(Tg)) mice that develop aggressive and lethal B cell lymphomas were made CD19 deficient (c-Myc(Tg)CD19â»/â»). Compared with c-Myc(Tg) and c-Myc(Tg)CD19âº/â» littermates, the median life span of c-Myc(Tg)CD19â»/â» mice was prolonged by 81-83% (p < 0.0001). c-Myc(Tg)CD19â»/â» mice also lived 42% longer than c-Myc(Tg) littermates following lymphoma detection (p < 0.01). Tumor cells in c-Myc(Tg) and c-Myc(Tg)CD19â»/â» mice were B lineage derived, had a similar phenotype with a large blastlike appearance, invaded multiple lymphoid tissues, and were lethal when adoptively transferred into normal recipient mice. Importantly, reduced lymphomagenesis in c-Myc(Tg)CD19â»/â» mice was not due to reductions in early B cell numbers prior to disease onset. In mechanistic studies, constitutive c-Myc expression enhanced CD19 expression and phosphorylation on active sites. Reciprocally, CD19 expression in c-Myc(Tg) B cells enhanced c-Myc phosphorylation at regulatory sites, sustained higher c-Myc protein levels, and maintained a balance of cyclin D2 expression over that of cyclin D3. These findings define a new and novel c-Myc:CD19 regulatory loop that positively influences B cell transformation and lymphoma progression.
Assuntos
Antígenos CD19/genética , Linfoma de Células B/imunologia , Linfoma de Células B/patologia , Proteínas Proto-Oncogênicas c-myc/genética , Transdução de Sinais/genética , Transdução de Sinais/imunologia , Animais , Antígenos CD19/metabolismo , Antígenos CD19/fisiologia , Subpopulações de Linfócitos B/imunologia , Subpopulações de Linfócitos B/metabolismo , Subpopulações de Linfócitos B/patologia , Progressão da Doença , Humanos , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , Linfoma de Células B/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Camundongos Transgênicos , Técnicas de Amplificação de Ácido Nucleico , Proteínas Proto-Oncogênicas c-myc/biossíntese , Proteínas Proto-Oncogênicas c-myc/fisiologia , Análise de SobrevidaRESUMO
B-cell receptor (BCR) ligation generates reactive oxygen intermediates (ROIs) that play a role in cellular responses. Although ROIs can oxidize all macromolecules, it was unclear which modifications control B-cell responses. In this study, we demonstrate the importance of the first oxidation product of cysteine, sulfenic acid, and its reversible formation in B-cell activation. Upon BCR crosslinking, B cells increase ROI levels with maximal production occurring within 15 min. Increased ROIs preceded elevated cysteine sulfenic acid, which localized to the cytoplasm and nucleus. Analysis of individual proteins revealed that the protein tyrosine phosphatases (PTPs) SHP-1, SHP-2, and PTEN, as well as actin, were modified to sulfenic acid following BCR ligation. Additionally, we used 5,5-dimethyl-1,3-cyclohexanedione (dimedone), a compound that covalently reacts with sulfenic acid to prevent its further oxidation or reduction, to determine the role of reversible cysteine sulfenic acid formation in regulating B-cell responses. Dimedone incubation resulted in a concentration-dependent block in anti-IgM-induced cell division, accompanied by a failure to induce capacitative calcium entry (CCE), and maintain tyrosine phosphorylation. These studies illustrate that reversible cysteine sulfenic acid formation is a mechanism by which B cells modulate pathways critical for activation and proliferation.
Assuntos
Linfócitos B/imunologia , Cisteína/análogos & derivados , Cisteína/metabolismo , Ativação Linfocitária , Espécies Reativas de Oxigênio/imunologia , Actinas/metabolismo , Animais , Linfócitos B/metabolismo , Transporte Biológico/efeitos dos fármacos , Divisão Celular/efeitos dos fármacos , Proliferação de Células , Cicloexanonas/farmacologia , Camundongos , PTEN Fosfo-Hidrolase/metabolismo , Fosforilação/efeitos dos fármacos , Proteína Tirosina Fosfatase não Receptora Tipo 11/metabolismo , Proteína Tirosina Fosfatase não Receptora Tipo 6/metabolismo , Receptores de Antígenos de Linfócitos BRESUMO
B-1b cells play a key role in producing Abs against T cell-independent type 2 Ags. However, the factors regulating Ab production by this unique B cell subset are not well understood. In this study, a detailed analysis of the B cell response to 2,4,6-trinitrophenol (TNP)-Ficoll was performed using normal mice. TNP-Ficoll delivered i.p. or i.v. induced rapid Ag-specific B-1b cell activation, expansion, isotype switching, and plasmablast/plasma cell differentiation. Ag-specific B-1b cell numbers peaked at day 5 and then gradually declined in the spleen but remained elevated in the peritoneal cavity beyond 40 d postimmunization. In addition to expressing CD43, CD44, and CD86, Ag-activated B-1b cells transiently expressed programmed cell death 1 (PD-1), which functionally suppressed BCR-induced B-1b cell in vitro proliferation when additional costimulatory signals were lacking. Inhibiting PD-1:PD-1 ligand interactions during TNP-Ficoll immunization significantly enhanced Ag-specific B-1b cell expansion and the frequency of IgG isotype switching and plasmablast/plasma cell differentiation. Remarkably, PD-1 mAb blockade during the first week following immunization resulted in significantly increased numbers of both splenic and bone marrow Ag-specific IgG3-secreting cells, but not IgM-secreting cells, at both early (day 5) and late (week 6) time points. Moreover, Ag-specific serum IgG3 levels, as well as IgG2c, IgG2b, and IgA levels, remained significantly elevated in PD-1 mAb-treated mice relative to control Ab-treated mice for ≥6 wk postimmunization. Thus, PD-1:PD-1 ligand interactions occurring shortly after initial T cell-independent type 2 Ag encounter play a critical role in suppressing Ag-specific B-1b cell expansion and the development of long-term IgG-producing bone marrow and spleen cells.
Assuntos
Antígenos T-Independentes/fisiologia , Subpopulações de Linfócitos B/citologia , Subpopulações de Linfócitos B/imunologia , Diferenciação Celular/imunologia , Regulação para Baixo/imunologia , Inibidores do Crescimento/fisiologia , Imunoglobulina G/biossíntese , Receptor de Morte Celular Programada 1/fisiologia , Animais , Células Cultivadas , Ficoll/análogos & derivados , Ficoll/farmacologia , Haptenos/fisiologia , Imunoglobulina G/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fatores de Tempo , Trinitrobenzenos/farmacologiaRESUMO
PURPOSE: The mechanism by which partial splenectomy preserves splenic immune function is unknown. Immunoglobulin (Ig) M memory B cells are critical for the immune response against encapsulated bacteria and are reduced in asplenic patients, although it is unknown whether partial splenectomy can preserve memory B cells. We hypothesized that IgM memory B cells (murine B-1a cells) would be preserved after partial splenectomy but not after total splenectomy in mice. METHODS: We performed total splenectomy (n = 17), partial splenectomy (n = 10), or sham laparotomy (n = 16) on C57BL/6J mice. Mice were killed on postoperative day 10 or 30, and peritoneal washings were analyzed by multiparameter flow cytometry for expression of murine B-1a cells (IgM(pos)IgD(dull)CD5(pos)B220(dull)). RESULTS: We found that B-1a cells were significantly reduced after both total and partial splenectomies compared with sham laparotomy in the early postoperative period, although normal levels of B-1a cells returned by postoperative day 30 in mice undergoing partial splenectomy but not total splenectomy. CONCLUSION: Partial splenectomy but not total splenectomy preserves the B-1a B-cell population in mice within 30 days after surgery. Maintenance of these critical B cells may contribute to the preservation of a splenic-dependent immune response after partial splenectomy.
Assuntos
Linfócitos B/imunologia , Imunoglobulina M , Memória Imunológica , Esplenectomia/métodos , Animais , Camundongos , Camundongos Endogâmicos C57BLRESUMO
BACKGROUND: Aberrant CD40 ligand (CD154) expression occurs on both T cells and B cells in human lupus patients, which is suggested to enhance B cell CD40 signaling and play a role in disease pathogenesis. Transgenic mice expressing CD154 by their B cells (CD154(TG)) have an expanded spleen B cell pool and produce autoantibodies (autoAbs). CD22 deficient (CD22(-/-)) mice also produce autoAbs, and importantly, their B cells are hyper-proliferative following CD40 stimulation ex vivo. Combining these 2 genetic alterations in CD154(TG)CD22(-/-) mice was thereby predicted to intensify CD40 signaling and autoimmune disease due to autoreactive B cell expansion and/or activation. METHODOLOGY/PRINCIPAL FINDINGS: CD154(TG)CD22(-/-) mice were assessed for their humoral immune responses and for changes in their endogenous lymphocyte subsets. Remarkably, CD154(TG)CD22(-/-) mice were not autoimmune, but instead generated minimal IgG responses against both self and foreign antigens. This paucity in IgG isotype switching occurred despite an expanded spleen B cell pool, higher serum IgM levels, and augmented ex vivo B cell proliferation. Impaired IgG responses in CD154(TG)CD22(-/-) mice were explained by a 16-fold expansion of functional, mature IL-10-competent regulatory spleen B cells (B10 cells: 26.7×10(6)±6 in CD154(TG)CD22(-/-) mice; 1.7×10(6)±0.4 in wild type mice, p<0.01), and an 11-fold expansion of B10 cells combined with their ex vivo-matured progenitors (B10+B10pro cells: 66×10(6)±3 in CD154(TG)CD22(-/-) mice; 6.1×10(6)±2 in wild type mice, p<0.01) that represented 39% of all spleen B cells. CONCLUSIONS/SIGNIFICANCE: These results demonstrate for the first time that the IL-10-producing B10 B cell subset has the capacity to suppress IgG humoral immune responses against both foreign and self antigens. Thereby, therapeutic agents that drive regulatory B10 cell expansion in vivo may inhibit pathogenic IgG autoAb production in humans.
Assuntos
Linfócitos B Reguladores/citologia , Linfócitos B Reguladores/metabolismo , Antígenos CD40/metabolismo , Transdução de Sinais , Animais , Autoanticorpos/biossíntese , Linfócitos B Reguladores/imunologia , Ligante de CD40/metabolismo , Contagem de Células , Imunidade Humoral/imunologia , Imunoglobulina G/biossíntese , Camundongos , Camundongos Endogâmicos C57BL , Fenótipo , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/metabolismoRESUMO
Peripheral B-cell numbers are tightly regulated by homeostatic mechanisms that influence the transitional and mature B-cell compartments and dictate the size and clonotypic diversity of the B-cell repertoire. B-lymphocyte stimulator (BLyS, a trademark of Human Genome Sciences, Inc.) plays a key role in regulating peripheral B-cell homeostasis. CD22 also promotes peripheral B-cell survival through ligand-dependent mechanisms. The B-cell subsets affected by the absence of BLyS and CD22 signals overlap, suggesting that BLyS- and CD22-mediated survival are intertwined. To examine this, the effects of BLyS insufficiency following neutralizing BLyS mAb treatment in mice also treated with CD22 ligand-blocking mAb were examined. Combined targeting of the BLyS and CD22 survival pathways led to significantly greater clearance of recirculating bone marrow, blood, marginal zone and follicular B cells than either treatment alone. Likewise, BLyS blockade further reduced bone marrow, blood and spleen B-cell numbers in CD22(-/-) mice. Notably, BLyS receptor expression and downstream signaling were normal in CD22(-/-) B cells, suggesting that CD22 does not directly alter BLyS responsiveness. CD22 survival signals were likewise intact in the absence of BLyS, as CD22 mAb treatment depleted blood B cells from mice with impaired BLyS receptor 3 (BR3) signaling. Finally, enforced BclxL expression, which rescues BR3 impairment, did not affect B-cell depletion following CD22 mAb treatment. Thus, the current studies support a model whereby CD22 and BLyS promote the survival of overlapping B-cell subsets but contribute to their maintenance through independent and complementary signaling pathways.
Assuntos
Fator Ativador de Células B/imunologia , Receptor do Fator Ativador de Células B/imunologia , Linfócitos B/imunologia , Homeostase/imunologia , Lectina 2 Semelhante a Ig de Ligação ao Ácido Siálico/imunologia , Transdução de Sinais/imunologia , Animais , Receptor do Fator Ativador de Células B/genética , Linfócitos B/citologia , Western Blotting , Proliferação de Células , Células Cultivadas , Citometria de Fluxo , Camundongos , Camundongos Endogâmicos C57BL , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Delineating the relative contributions of B lymphocytes during the course of autoimmune disease has been difficult. Therefore, the effects of depleting all mature B cells using a potent CD20 mAb, or of depleting circulating and marginal zone B cells using a ligand-blocking CD22 mAb, were compared in NZB/W F(1) mice, a model for human systemic lupus erythematosus. Single low-dose mAb treatments depleted B cells efficiently in both NZB/W F(1) and C57BL/6 mice. Prophylactic B cell depletion by repeated CD20 mAb treatments prolonged survival during pristane-accelerated lupus in NZB/W F(1) mice, whereas CD22 mAb had little effect. Despite effective B cell depletion, neither mAb treatment prevented autoantibody generation. In addition, CD20, CD22, and control mAb-treated NZB/W F(1) mice developed anti-mouse IgG autoantibodies in contrast to parental NZB and NZW strains, which may have reduced the effectiveness of B cell depletion. Despite this, low-dose CD20 mAb treatment initiated in 12-28-wk-old mice, and administered every 4 wk thereafter, significantly delayed spontaneous disease in NZB/W F(1) mice. By contrast, B cell depletion initiated in 4-wk-old mice hastened disease onset, which paralleled depletion of the IL-10-producing regulatory B cell subset called B10 cells. B10 cells were phenotypically similar in NZB/W F(1) and C57BL/6 mice, but were expanded significantly in young NZB/W F(1) mice. Thus, B cell depletion had significant effects on NZB/W F(1) mouse survival that were dependent on the timing of treatment initiation. Therefore, distinct B cell populations can have opposing protective and pathogenic roles during lupus progression.