RESUMO
Endogenous glycosylated Hev b 2 (endo-ß-1,3-glucanase) from Hevea brasiliensis is an important latex allergen that is recognized by IgE antibodies from patients who suffer from latex allergy. The carbohydrate moieties of Hev b 2 constitute a potentially important IgE-binding epitope that could be responsible for its cross-reactivity. Here, the structure of the endogenous isoform II of Hev b 2 that exhibits three post-translational modifications, including an N-terminal pyroglutamate and two glycosylation sites at Asn27 and at Asn314, is reported from two crystal polymorphs. These modifications form a patch on the surface of the molecule that is proposed to be one of the binding sites for IgE. A structure is also proposed for the most important N-glycan present in this protein as determined by digestion with specific enzymes. To analyze the role of the carbohydrate moieties in IgE antibody binding and in human basophil activation, the glycoallergen was enzymatically deglycosylated and evaluated. Time-lapse automated video microscopy of basophils stimulated with glycosylated Hev b 2 revealed basophil activation and degranulation. Immunological studies suggested that carbohydrates on Hev b 2 represent an allergenic IgE epitope. In addition, a dimer was found in each asymmetric unit that may reflect a regulatory mechanism of this plant defence protein.
Assuntos
Antígenos de Plantas/química , Basófilos/efeitos dos fármacos , Celulase/química , Hevea/química , Imunoglobulina E/química , Proteínas de Plantas/química , Sequência de Aminoácidos , Antígenos de Plantas/imunologia , Antígenos de Plantas/isolamento & purificação , Antígenos de Plantas/farmacologia , Teste de Degranulação de Basófilos , Basófilos/citologia , Basófilos/imunologia , Sítios de Ligação , Sequência de Carboidratos , Células Cultivadas , Celulase/imunologia , Celulase/isolamento & purificação , Celulase/farmacologia , Cristalografia por Raios X , Ácido Glutâmico/metabolismo , Glicosilação , Humanos , Imunoglobulina E/imunologia , Hipersensibilidade ao Látex/imunologia , Modelos Moleculares , Dados de Sequência Molecular , Proteínas de Plantas/imunologia , Proteínas de Plantas/isolamento & purificação , Proteínas de Plantas/farmacologia , Ligação Proteica , Processamento de Proteína Pós-Traducional , Estrutura Quaternária de Proteína , Imagem com Lapso de TempoRESUMO
Basophils were discovered by Paul Ehrlich in 1879 and represent the least abundant granulocyte population in mammals. The relative rarity of basophils and their phenotypic similarities with mast cells resulted in this cell lineage being historically overlooked, both clinically and experimentally. However, recent studies in human subjects and murine systems have shown that basophils perform nonredundant effector functions and significantly contribute to the development and progression of TH2 cytokine-mediated inflammation. Although the potential functions of murine and human basophils have provoked some controversy, recent genetic approaches indicate that basophils can migrate into lymphoid tissues and, in some circumstances, cooperate with other immune cells to promote optimal TH2 cytokine responses in vivo. This article provides a brief historical perspective on basophil-related research and discusses recent studies that have identified previously unappreciated molecules and pathways that regulate basophil development, activation, and function in the context of allergic inflammation. Furthermore, we highlight the unique effector functions of basophils and discuss their contributions to the development and pathogenesis of allergic inflammation in human disease. Finally, we discuss the therapeutic potential of targeting basophils in preventing or alleviating the development and progression of allergic inflammation.
Assuntos
Basófilos/imunologia , Hipersensibilidade Imediata/imunologia , Hipersensibilidade Imediata/fisiopatologia , Inflamação/imunologia , Inflamação/fisiopatologia , Animais , Basófilos/citologia , Citocinas/metabolismo , Humanos , Hipersensibilidade Imediata/metabolismo , Inflamação/metabolismo , Camundongos , Células Th2/imunologia , Células Th2/metabolismoRESUMO
Basophils co-express FcεRIα and CD49b, the α-2 chain of integrin-type receptor VLA-2 (α2ß1), which recognizes type-1 collagen as a major natural ligand. The physiological relevance of this integrin for interactions with extracellular bone marrow matrix remains unknown. Herein, we examined the expression of several receptors of this family by bone marrow-derived basophils sorted either ex-vivo or after culture with IL-3. Having established that both populations display CD49d, CD49e and CD49f (α-4, α-5 and α-6 integrins subunits, respectively), we addressed receptor functions by measuring migration, adhesion, proliferation and survival after interacting with matched natural ligands. Type I collagen, laminin and fibronectin promoted basophil migration/adhesion, the former being the most effective. None of these ligands affected basophil viability and expansion. Interactions between basophils and extracellular matrix are likely to play a role in situ, as supported by confocal 3D cell imaging of femoral bone marrow sections, which revealed basophils exclusively in type-1 collagen-enriched niches that contained likewise laminin and fibronectin. This is the first evidence for a structure/function relationship between basophils and extracellular matrix proteins inside the mouse bone marrow.
Assuntos
Basófilos/citologia , Células da Medula Óssea/citologia , Movimento Celular , Matriz Extracelular , Animais , Basófilos/metabolismo , Células da Medula Óssea/metabolismo , Adesão Celular , Células Cultivadas , Feminino , Imunofluorescência , Perfilação da Expressão Gênica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Thirty adult agoutis (Dasyprocta primnolopha) from the Nucleus of Study and Preservation of Wild Animals at the Federal University of Piauí were used. Blood scrubs of these animals were colored by the Leishman method and analyzed in light microscopy. The cells had been measured using programs that analyze images (Leica QWin - Image Processing and Analysis Software). Mature erythrocytes, basophil reticulocytes, lymphocytes, eosinophils, neutrophils, monocytes, and thrombocytes were identified. Agoutis' erythrocytes presented elliptical form, without nucleus with an average diameter of 5.64 micromeres ± 0.38. The lymphocytes are spherical cells with scarce cytoplasm, dense and with a very centralized rounded nucleus measuring an average diameter of 13.20 micromeres ± 0.35. The monocytes are slightly basophilic, with a spherical nucleus, central constriction, and an average diameter of 20.59 micromeres ± 0.32. The neutrophils are spherical, with a polymorphic lobulated nucleus, with an average diameter of 11.2 micromeres ± 0.20. The eosinophils are spherical with lobulated nucleus and with an average diameter of 14.25 micromeres ± 0.36. Only five basophils were observed, with abundance of cytoplasmic granules with 9.8 micrometers of diameter ± 0.30. Thrombocytopenic pleomorphism was frequent. There were similarities in the cellular constituents in peripheral blood of agoutis and of other rodents and humans. The cellular types from the peripheral blood, the morphology, and morphometry of the blood's cells did not vary according to sex.
Assuntos
Células Sanguíneas/citologia , Roedores/anatomia & histologia , Animais , Basófilos/citologia , Plaquetas/citologia , Eosinófilos/citologia , Eritrócitos/citologia , Feminino , Linfócitos/citologia , Masculino , Monócitos/citologia , Neutrófilos/citologiaRESUMO
This study investigated the development of resistance in guinea pigs to nymphs of Amblyomma triste ticks after repeated infestations. Guinea pigs were infested thrice, at 30-day intervals, with 30 nymphs of A. triste per animal per infestation. Acquisition of resistance was evaluated by determining: nymph yielding rate, engorgement period, and weight. Skin biopsies of tick bite sites were collected at 24, 48, and 96 h after tick attachment for inflammatory cell counts. Engorged nymphs weighed 5.53 mg +/- 1.9 in re-infested hosts (56.6% less than in primary infestation) and took 6.9 days +/- 2.16 to feed in the third infestation (14.5% more than in the first infestation). Guinea pigs yielded 78%+/- 7.2 of nymphs in the re-infestation (11.6% less than in the primary infestation). In addition, a marked increase in basophil influx was observed from the first infestation onward; 69% of infiltrated cells were basophils in re-infested hosts 24 h after tick attachment. No basophils were seen at this time in primary infested animals. That number increased to 84.7% 48 h post attachment in re-infested hosts (73.2% more than in the primary infested ones) and decreased markedly 96 h post attachment in both groups (2.6% and 1% of basophils in the third and first infestation, respectively). We conclude that guinea pigs acquire resistance against nymphs of A. triste ticks after repeated infestations and that a cutaneous basophilia must play a crucial role in such a mechanism.
Assuntos
Basófilos/imunologia , Dermatopatias/imunologia , Carrapatos/fisiologia , Animais , Basófilos/citologia , Feminino , Cobaias , Dermatopatias/patologiaRESUMO
Complement may be important for immunity to infection with parasitic helminths, by promoting the recruitment of leukocytes to infected tissues and by modulating the function of cytotoxic effector leukocytes. However, the importance of complement in vivo during helminth infection is poorly understood. In this study, mice lacking classical (C1q-deficient), alternative (factor B-deficient) or all pathways of complement activation (C3-deficient) were used to assess the role of complement in immunity to the nematode Nippostrongylus brasiliensis. Double-mutant complement-deficient/IL-5 transgenic (Tg) mice were used to determine if complement is required for the strong eosinophil-dependent resistance to this parasite. Complement activation on larvae (C3 deposition), extracellular eosinophil peroxidase activity, larval aggregation and eosinophil recruitment to the skin 30 min post-injection (p.i.) of larvae were reduced in factor B-deficient mice. Inhibition of the C5a receptor with the antagonist PMX53 impaired eosinophil and neutrophil recruitment to the skin. C3 deposition on larvae was minimal by 150 min p.i. and at this time cell adherence, larval aggregation, eosinophil recruitment and degranulation were complement-independent. Factor B and C3 deficiency were associated with higher lung larval burdens in primary infections. Complement-deficient/IL-5 Tg mice were highly resistant to N. brasiliensis, suggesting that eosinophils can limit infection in a complement-independent manner. Potent secondary immunity was similarly complement-independent. In conclusion, although the alternative pathway is important for parasite recognition and leukocyte recruitment early in N. brasiliensis infections, the parasite soon becomes resistant to complement and other factors can compensate to promote eosinophil-dependent immunity.
Assuntos
Proteínas do Sistema Complemento/imunologia , Eosinófilos/imunologia , Imunidade Celular/imunologia , Imunidade Inata/imunologia , Nippostrongylus/imunologia , Animais , Basófilos/citologia , Basófilos/imunologia , Basófilos/parasitologia , Adesão Celular , Degranulação Celular/imunologia , Movimento Celular , Complemento C3/imunologia , Eosinófilos/citologia , Eosinófilos/parasitologia , Eosinófilos/fisiologia , Feminino , Fertilidade , Intestinos/imunologia , Intestinos/parasitologia , Larva/citologia , Pulmão/imunologia , Pulmão/parasitologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Infiltração de Neutrófilos/imunologia , Nippostrongylus/citologia , Pele/imunologia , Pele/parasitologia , Infecções por Strongylida/imunologiaRESUMO
Recent advances on the pathogenesis of chronic urticaria have defined a group of patients with autoantibodies directed to the IgE or to the alpha chain of the Fc high affinity receptor of IgE, Fc epsilon RI alpha. These antibodies are detected in vivo through the autologous serum test (AST) and in vitro with a variety of techniques. We here describe 37 patients with chronic urticaria, 28 female and 9 male, with a f/m ratio of 3.1. Mean age at onset was 36.5 years (range 16-78). AST was positive in 25 (68%) of 37 patients. Serum induced a wheal significantly larger than plasma (122 +/- 78 mm2 vs 57 +/- 66 mm2, p < 0.05). Median persistence of the chronic urticaria, estimated by Kaplan-Meyer analysis, was 437 days, with no difference between AST(+) and AST(-) patients (437 vs. 369, p = 0.18). Mean IgE concentration was 157 +/- 173 IU/mL, as expected in an unselected population. Basophil count was lower in patients compared with controls (17 +/- 12 cel/microL vs. 43 +/- 27 cel/microL, p < 0.008). Only sera from 2/7 (28.6%) patients AST (+) and very low basophil count consistently induced expression of CD63. This effect was abrogated in non-releasing basophils, confirming the presence of antibodies directed to the Fc epsilon RI alpha-IgE. We conclude that functional antibodies are present in only a minority of patients and that their identification does not predict the outcome.
Assuntos
Autoanticorpos/imunologia , Basófilos/imunologia , Urticária/imunologia , Adolescente , Adulto , Idoso , Agranulocitose/imunologia , Antígenos CD/análise , Autoanticorpos/análise , Basófilos/citologia , Doença Crônica , Feminino , Seguimentos , Humanos , Imunoglobulina E/sangue , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Glicoproteínas da Membrana de Plaquetas/análise , Receptores de IgE/imunologia , Tetraspanina 30 , Urticária/sangueRESUMO
In the peripheral blood of the roadside hawk, Buteo magnirostris, the following types of granulocytic leucocytes were identified: heterophil, eosinophil and basophil. The heterophils presented acidophilic and spindle shaped granules, the eosinophils possess spherical eosinophilic granules and the basophils showed spherical and basophilic granules. The heterophils and eosinophils presented positive cytochemical reaction to glycogen and basic polyaminoacid, while the eosinophils presented sudanophilic granules, which were also positive for myeloperoxidase. The heterophils, alone, presented positivity for acid phosphatase in some granules and immunoreactivity to TGF-beta1 was observed only in the cytoplasm of the eosinophils. Electron microscopy demonstrated the heterophil granules as predominantly spindle shaped, being strongly electron-dense, while the eosinophils had numerous uniformly electron-dense spherical granules and the basophils presented three different types of granules identified according to their electron-density and the aspect of their matrix.
Assuntos
Granulócitos/fisiologia , Aves Predatórias/fisiologia , Animais , Basófilos/citologia , Basófilos/imunologia , Basófilos/fisiologia , Basófilos/ultraestrutura , Eosinófilos/citologia , Eosinófilos/imunologia , Eosinófilos/fisiologia , Eosinófilos/ultraestrutura , Granulócitos/citologia , Granulócitos/imunologia , Granulócitos/ultraestrutura , Imuno-Histoquímica , Microscopia Eletrônica , Aves Predatórias/imunologia , Fator de Crescimento Transformador beta/imunologiaRESUMO
Recent advances on the pathogenesis of chronic urticaria have defined a group of patients with autoantibodies directed to the IgE or to the alpha chain of the Fc high affinity receptor of IgE, Fc epsilon RI alpha. These antibodies are detected in vivo through the autologous serum test (AST) and in vitro with a variety of techniques. We here describe 37 patients with chronic urticaria, 28 female and 9 male, with a f/m ratio of 3.1. Mean age at onset was 36.5 years (range 16-78). AST was positive in 25 (68%) of 37 patients. Serum induced a wheal significantly larger than plasma (122 +/- 78 mm2 vs 57 +/- 66 mm2, p < 0.05). Median persistence of the chronic urticaria, estimated by Kaplan-Meyer analysis, was 437 days, with no difference between AST(+) and AST(-) patients (437 vs. 369, p = 0.18). Mean IgE concentration was 157 +/- 173 IU/mL, as expected in an unselected population. Basophil count was lower in patients compared with controls (17 +/- 12 cel/microL vs. 43 +/- 27 cel/microL, p < 0.008). Only sera from 2/7 (28.6%) patients AST (+) and very low basophil count consistently induced expression of CD63. This effect was abrogated in non-releasing basophils, confirming the presence of antibodies directed to the Fc epsilon RI alpha-IgE. We conclude that functional antibodies are present in only a minority of patients and that their identification does not predict the outcome (AU)
Assuntos
Humanos , Masculino , Feminino , Adolescente , Adulto , Pessoa de Meia-Idade , Idoso , RESEARCH SUPPORT, NON-U.S. GOVT , Autoanticorpos/imunologia , Basófilos/imunologia , Urticária/imunologia , Autoanticorpos/análise , Basófilos/citologia , Doença Crônica , Urticária/sangue , Contagem de Leucócitos , Antígenos CD , Receptores de IgE/imunologia , Testes Cutâneos/métodos , Hipersensibilidade Imediata/sangue , SeguimentosAssuntos
Inflamação/classificação , Inflamação/história , Basófilos/citologia , Eosinófilos/citologia , Inflamação/etiologia , Inflamação/patologia , Inflamação/tratamento farmacológico , Linfócitos/classificação , Linfócitos/citologia , Mastócitos/citologia , Monócitos/citologia , Neutrófilos/citologiaAssuntos
Mitose , Pâncreas/crescimento & desenvolvimento , Animais , Autorradiografia , Basófilos/citologia , Basófilos/metabolismo , Peso Corporal , Cromossomos/crescimento & desenvolvimento , Cromossomos/metabolismo , Tecido Conjuntivo/metabolismo , Células do Tecido Conjuntivo , DNA/biossíntese , Feminino , Histocitoquímica , Cinética , Masculino , Microscopia Eletrônica , Tamanho do Órgão , Pâncreas/citologia , Pâncreas/metabolismo , Ratos , Timidina/metabolismo , Fatores de Tempo , TrítioRESUMO
Ninety cases of leprosy were examined. All cases except two were under treatment with the sulphones. A hypochromic, normocytic anaemia was present in 80 percent of males and 60 percent of females. This had been reported previously in leprosy and also in patients under treatment with the sulphones. Nine per cent of cases showed a marked basophilia and basophils were present in 26 percent of cases. The relationship is not understood. Twenty-five per cent of cases showed the presence of atypical monocytes, a finding which has previously been observed in leprosy. A contradictory tendency to thrombocytopenia with a shortened bleeding time was found, with normal clotting and prothrombin times. The significance of these findings is not understood. (AU)