RESUMO
Der p 1 is one of the major allergenic molecules of Dermatophagoides pteronyssinus, causing house dust mite (HDM) allergy. The pathological B cells produce allergen-specific IgE antibodies that mediate the hypersensitivity reaction, therefore the selective elimination of these B cells is a legitimate therapeutic goal in allergy. Chimeric molecule Dp51-72 able to cross-link B cell inhibitory complement receptor type 1 and BCR on Der p 1-specific B cells was constructed. The signalling capabilities of this molecule have been tested on human B cells. A humanized mouse model of HDM allergy has been used to test the in vivo effects of the chimeric molecule administration. Administering the chimeric molecule to immunodeficient Rag2- γc- mice transferred with PBMCs from allergic patients resulted in reduction of allergen-specific IgE antibodies in the sera, and reduced infiltration of immune cells in lung histology preparations. Reduced numbers of human CD45+ and CD4+ cells in the lungs as well as inhibition of mast cell degranulation were also observed. The treatment with Dp51-72 chimera significantly decreased the local levels of anti-Dpt IgE antibodies in the bronchoalveolar lavage fluid (BALF). The binding of the chimeric molecule to tonsillar B cells triggers the tyrosine phosphorylation of 30-32 kDa protein, which is most likely involved in the inhibitory process. Administration of constructed chimeric molecules to humanized mice with developed inflammation resulted in specific suppression of disease-associated IgE antibody-producing cells and preserved lung histology. This effective approach could be further developed into a therapeutic agent for treatment of patients with HDM allergy.
Assuntos
Alergia a Ácaros , Hipersensibilidade , Receptores de Antígenos de Linfócitos B , Animais , Humanos , Camundongos , Alérgenos , Antígenos de Dermatophagoides , Modelos Animais de Doenças , Proteínas de Ligação a DNA , Alergia a Ácaros/metabolismo , Imunoglobulina E , Proteínas Nucleares , Linfócitos B/efeitos dos fármacos , Receptores de Antígenos de Linfócitos B/efeitos dos fármacosRESUMO
Integrins are cell membrane receptors that are involved in essential physiological and serious pathological processes. Their main role is to ensure a closely regulated link between the extracellular matrix and the intracellular cytoskeletal network enabling cells to react to environmental stimuli. Complement receptor type 3 (CR3, αMß2, CD11b/CD18) and type 4 (CR4, αXß2, CD11c/CD18) are members of the ß2-integrin family expressed on most white blood cells. Both receptors bind multiple ligands like iC3b, ICAM, fibrinogen or LPS. ß2-integrins are accepted to play important roles in cellular adhesion, migration, phagocytosis, ECM rearrangement and inflammation. Several pathological conditions are linked to the impaired functions of these receptors. CR3 and CR4 are generally thought to mediate overlapping functions in monocytes, macrophages and dendritic cells, therefore the potential distinctive role of these receptors has not been investigated so far in satisfactory details. Lately it has become clear that a functional segregation has evolved between the two receptors regarding phagocytosis, cellular adhesion and podosome formation. In addition to their tasks on myeloid cells, the expression and function of CR3 and CR4 on lymphocytes have also gained interest recently. The picture is further complicated by the fact that while these ß2-integrins are expressed by immune cells both in mice and humans, there are significant differences in their expression level, functions and the pathological consequences of genetic defects. Here we aim to summarize our current knowledge on CR3 and CR4 and highlight the functional differences between these receptors, involving their expression in myeloid and lymphoid cells of both men and mice.
Assuntos
Complemento C3/metabolismo , Complemento C4/metabolismo , Linfócitos/metabolismo , Células Mieloides/metabolismo , Animais , Complemento C3/imunologia , Complemento C4/imunologia , Humanos , Linfócitos/imunologia , Masculino , CamundongosRESUMO
The chemical signatures emitted by fungal substrates are key components for mycophagous insects in the search for food source or for suitable oviposition sites. These volatiles are usually emitted by the fruiting bodies and mycelia. The volatiles attract fungivorous insects, like flowers attract pollinators; certain flowers mimic the shape of mushroom fruiting bodies and even produce a typical mushroom odor to exploit on fungus-insect mutualism. There are numerous insects which are mycophagous or eat fungi additionally, but only a few are considered a threat in agriculture. Lycoriella ingenua is one of the most serious pests in mushroom cultivation worldwide. Here we attempt to examine the role of environmental volatiles upon behavioral oviposition preference. In two-choice bioassays, fungus gnats preferred uncolonized compost compared to colonized compost but preferred colonized compost against nothing. However, when colonized compost was paired against distilled water, no significant choice was observed. The comparison of fresh casing material and mycelium colonized casing material resulted in no significant preference. From colonized compost headspace, three antennally active volatiles were isolated by gas chromatography coupled with electroantennography and subsequently identified with gas chromatography coupled mass spectrometry as 1-hepten-3-ol, 3-octanone and 1-octen-3-ol. In behavioral assays the addition of said synthetic volatiles to uncolonized compost separately and in combination to mimic colonized compost resulted in avoidance. We thus partially elucidate the role of fungal volatiles in the habitat seeking behavior of Lycoriella ingenua.
Assuntos
Agaricus/crescimento & desenvolvimento , Compostagem , Dípteros/fisiologia , Micélio/crescimento & desenvolvimento , Percepção Olfatória/fisiologia , Compostos Orgânicos Voláteis/química , Animais , Comportamento Animal/efeitos dos fármacos , Sinais (Psicologia) , Controle de Insetos/métodos , Oviposição , Compostos Orgânicos Voláteis/farmacologiaRESUMO
The complement system is a major component of immune defense. Activation of the complement cascade by foreign substances and altered self-structures may lead to the elimination of the activating agent, and during the enzymatic cascade, several biologically active fragments are generated. Most immune regulatory effects of complement are mediated by the activation products of C3, the central component. The indispensable role of C3 in opsonic phagocytosis as well as in the regulation of humoral immune response is known for long, while the involvement of complement in T-cell biology have been revealed in the past few years. In this review, we discuss the immune modulatory functions of C3-derived fragments focusing on their role in processes which have not been summarized so far. The importance of locally synthesized complement will receive special emphasis, as several immunological processes take place in tissues, where hepatocyte-derived complement components might not be available at high concentrations. We also aim to call the attention to important differences between human and mouse systems regarding C3-mediated processes.
Assuntos
Complemento C3/imunologia , Fígado/imunologia , Peptídeos/imunologia , Fagocitose/imunologia , Linfócitos T/imunologia , Animais , Humanos , Imunidade Celular , Imunidade Humoral , Imunomodulação , Camundongos , Modelos AnimaisRESUMO
The effects of distinct UV-A and UV-B radiations were studied on etiolated pea (Pisum sativum L.) epicotyls. Emission spectra of the native protochlorophyll and protochlorophyllide forms were measured when epicotyls were excited with 360 or 300 nm light. The UV-A (360 nm) excited mainly the non-enzyme-bound monomers of protochlorophyll and protochlorophyllide and the UV-B (300 nm) excited preferentially the flash-photoactive protochlorophyllide complexes. These latter complexes converted into short- and long-wavelength chlorophyllide forms at 10-s illumination with both wavelength irradiations. As the spectral changes were very small, the effects of longer illumination periods were studied. Room temperature fluorescence emission spectra were measured from the same epicotyl spots before and after irradiation with various wavelengths between 280 and 360 nm for 15 min and the "illuminated" minus "dark" difference spectra were calculated. Both the UV-A and the UV-B irradiations caused photoreduction of protochlorophyllide into chlorophyllide. At 10 µmol photons m-2 s-1, the photoreduction rates were similar, however, at 60 µmol photons m-2 s-1, the UV-B irradiation was more effective in inducing chlorophyllide formation than the UV-A. The action spectra of protochlorophyllide plus protochlorophyll loss and chlorophyllide production showed that the radiation around 290 nm was the most effective in provoking protochlorophyllide photoreduction and the UV light above 320 nm caused strong bleaching. These results show that the effect of the UV radiation should be considered when discussing the protochlorophyllide-chlorophyllide photoreduction during germination and as a part of the regeneration of the photosynthetic apparatus proceeding in the daily run of photosynthesis.
Assuntos
Clorofilídeos/metabolismo , Pisum sativum/metabolismo , Protoclorifilida/metabolismo , Clorofila/análogos & derivados , Clorofila/metabolismo , Clorofila/efeitos da radiação , Clorofilídeos/efeitos da radiação , Escuridão , Fluorescência , Microscopia de Fluorescência , Oxirredução , Pisum sativum/efeitos da radiação , Processos Fotoquímicos , Fotossíntese , Folhas de Planta/química , Folhas de Planta/metabolismo , Protoclorifilida/efeitos da radiação , Raios UltravioletaRESUMO
The European pepper moth (Duponchelia fovealis, Lepidoptera, Crambidae, Spilomelinae) is an invasive pest of greenhouses in many countries, causing serious damages to horticultural plants. Coupled gas chromatographic-electroantennographic detection analysis of the female gland extract revealed two antennally active peaks. Using coupled gas chromatography-mass spectrometry (GC-MS), one was identified as (Z)-11-hexadecenal (Z11-16:Ald); however, further analysis on different types of capillary columns indicated that the second active compound has two different isomers, (E)-13-octadecenal (E13-18:Ald) and (Z)-13-octadecenal (Z13-18:Ald). The approximate ratio of E13-18:Ald, Z13-18:Ald and Z11-16:Ald in the crude pheromone gland extract was 10:1:0.1, respectively. Single sensillum recordings showed that there was one sensory neuron that responded with a high amplitude spike to both E13-18:Ald and Z13-18:Ald, while another neuron housed in the same sensillum responded to Z11-16:Ald. Field evaluation of the identified compounds indicated that the E13-18:Ald was necessary to evoke the attraction of males; although the presence of Z13-18:Ald and Z11-16:Ald increased the catches in traps. The highest number of caught males was achieved when E13-18:Ald, Z13-18:Ald and Z11-16:Ald were present in baits in the same ratio as in the female gland extract. This pheromone can be used in a monitoring strategy and could potentially lead to the development of mating disruption.
Assuntos
Ambiente Controlado , Espécies Introduzidas , Mariposas/metabolismo , Atrativos Sexuais/análise , Atrativos Sexuais/biossíntese , Animais , Bioensaio , Fenômenos Eletrofisiológicos , Feminino , Mariposas/fisiologia , Atrativos Sexuais/químicaRESUMO
Cannabinoid (CB) and opioid systems are both involved in analgesia, food intake, mood and behavior. Due to the co-localization of µ-opioid (MOR) and CB1 receptors in various regions of the central nervous system (CNS) and their ability to form heterodimers, bivalent ligands targeting to both these systems may be good candidates to investigate the existence of possible cross-talking or synergistic effects, also at sub-effective doses. In this work, we selected from a small series of new Rimonabant analogs one CB1R reverse agonist to be conjugated to the opioid fragment Tyr-D-Ala-Gly-Phe-NH2. The bivalent compound (9) has been used for in vitro binding assays, for in vivo antinociception models and in vitro hypothalamic perfusion test, to evaluate the neurotransmitters release.
Assuntos
Peptídeos Opioides/farmacologia , Piperidinas/farmacologia , Pirazóis/farmacologia , Receptor CB1 de Canabinoide/metabolismo , Receptores Opioides/metabolismo , Animais , Humanos , Ligantes , Camundongos , Peptídeos Opioides/química , Peptídeos Opioides/metabolismo , Piperidinas/metabolismo , Pirazóis/metabolismo , RimonabantoRESUMO
The photoreduction and photooxidation processes of different protochlorophyll(ide) forms were studied in the innermost leaves of cabbage (Brassica oleracea var. capitata L.) under monochromatic irradiations. Room-temperature fluorescence emission spectra were measured from the same leaf spots before and after illumination to follow the wavelength dependence of the photochemical reactions. Short-wavelength light of 7 µmol photons m(-2) s(-1) (625-630 nm) provoked mainly bleaching, and longer wavelengths (630-640 nm) caused both bleaching and photoreduction, while above 640 nm resulted in basically photoreduction. When bleached leaves were kept in darkness at room temperature, all protochlorophyll(ide) forms regenerated during 72 h. Oxygen-reduced environment decreased the extent of bleaching suggesting the involvement of reactive oxygen species. These results confirm that the short-wavelength, 628 nm absorbing, and 633 nm emitting protochlorophyll(ide) form in etiolated cabbage leaves sensibilizes photooxidation. However, the 628 nm light at low intensities stimulates the photoreduction of the longer wavelength protochlorophyllide forms. Kinetic measurements showed that photoreduction saturates at a low PFD (photon flux density) compared to bleaching, suggesting that the quantum yield of photoreduction is higher than that of bleaching.
Assuntos
Brassica/metabolismo , Clorofila/análogos & derivados , Folhas de Planta/metabolismo , Protoclorifilida/metabolismo , Brassica/química , Clorofila/metabolismo , Fluorescência , Luz , Oxirredução , Oxigênio/metabolismo , Processos Fotoquímicos , Folhas de Planta/química , Luz SolarRESUMO
B cells are efficiently activated by CpG oligodeoxynucleotides (ODNs) to produce pro-inflammatory cytokines and antibody (Ab). Here, we describe a so far unidentified, spleen tyrosine kinase (Syk)-dependent pathway, which is indispensable for CpG-induced human B cell activation. We show that triggering of B cells by CpG results in Syk and src kinase phosphorylation, proliferation, as well as cytokine and Ab production independent of the BCR. Notably, all these functions are abrogated when Syk is inhibited. We demonstrate that CpG-induced Syk activation originates from the cell surface in a TLR9-dependent manner. While inhibition of Syk does not influence the uptake of CpG ODNs, activation of the kinase is a prerequisite for the delivery of CpG into TLR9-containing endolysosomes and for the CpG-induced up-regulation of TLR9 expression. Our results reveal an alternative, Syk-dependent pathway of CpG-induced B cell stimulation, which is initiated at the plasma membrane and seems to be an upstream requirement for endosomal TLR9-driven B cell proliferation and differentiation.
Assuntos
Linfócitos B/imunologia , Ilhas de CpG/genética , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Oligodesoxirribonucleotídeos/metabolismo , Proteínas Tirosina Quinases/metabolismo , Receptor Toll-Like 9/metabolismo , Diferenciação Celular/imunologia , Proliferação de Células , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Ativação Linfocitária/genética , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fator 88 de Diferenciação Mieloide/antagonistas & inibidores , Fator 88 de Diferenciação Mieloide/metabolismo , NF-kappa B/metabolismo , Oligodesoxirribonucleotídeos/imunologia , Fosforilação , Ligação Proteica , Proteínas Tirosina Quinases/antagonistas & inibidores , Interferência de RNA , RNA Interferente Pequeno , Quinase Syk , Receptor Toll-Like 9/biossíntese , Receptor Toll-Like 9/genética , Regulação para Cima , Quinases da Família src/metabolismoRESUMO
Fentanyl is a powerful opiate analgesic typically used for the treatment of severe and chronic pain, but its prescription is strongly limited by the well-documented side-effects. Different approaches have been applied to develop strong analgesic drugs with reduced pharmacologic side-effects. One of the most promising is the design of multitarget drugs. In this paper we report the synthesis, characterization and biological evaluation of twelve new 4-anilidopiperidine (fentanyl analogues). In vivo hot-Plate test, shows a moderate antinociceptive activity for compounds OMDM585 and OMDM586, despite the weak binding affinity on both µ and δ-opioid receptors. A strong inverse agonist activity in the GTP-binding assay was revealed suggesting the involvement of alternative systems in the brain. Fatty acid amide hydrolase inhibition was evaluated, together with binding assays of cannabinoid receptors. We can conclude that compounds OMDM585 and 586 are capable to elicit antinociception due to their multitarget activity on different systems involved in pain modulation.
Assuntos
Analgésicos/farmacologia , Carbamatos/análise , Piperidinas/farmacologia , Ureia/análise , Analgésicos/química , Animais , Feminino , Cobaias , Masculino , Camundongos , Piperidinas/química , Ratos , Ratos Wistar , Análise Espectral/métodosRESUMO
Hypersensitivity reactions to particulate drugs can partly be caused by complement activation and represent a major complication during intravenous application of nanomedicines. Several liposomal and micellar drugs and carriers, and therapeutic antibodies, were shown to activate complement and induce complement activation-related pseudoallergy (CARPA) in model animals. To explore the possible use of the natural complement inhibitor factor H (FH) against CARPA, we examined the effect of FH on complement activation induced by CARPAgenic drugs. Exogenous FH inhibited complement activation induced by the antifungal liposomal Amphotericin-B (AmBisome), the widely used solvent of anticancer drugs Cremophor EL, and the anticancer monoclonal antibody rituximab in vitro. An engineered form of FH (mini-FH) was more potent inhibitor of Ambisome-, Cremophor EL- and rituximab-induced complement activation than FH. The FH-related protein CFHR1 had no inhibitory effect. Our data suggest that FH or its derivatives may be considered in the pharmacological prevention of CARPA. FROM THE CLINICAL EDITOR: Although liposomes and micelles are already in use in the clinical setting as drug carriers, there remains the potential problem of hypersensitivity due to complement activation. In this article, the authors investigated the use of complement inhibitor factor H (FH) on complement activation and showed good efficacy. The results would therefore suggest the potential application of complement inhibitor in the future.
Assuntos
Ativação do Complemento/efeitos dos fármacos , Fator H do Complemento/administração & dosagem , Hipersensibilidade a Drogas/tratamento farmacológico , Lipossomos/efeitos adversos , Ativação do Complemento/imunologia , Fator H do Complemento/imunologia , Portadores de Fármacos/efeitos adversos , Hipersensibilidade a Drogas/imunologia , Hipersensibilidade a Drogas/patologia , Voluntários Saudáveis , Humanos , Micelas , Nanomedicina , Neoplasias/tratamento farmacológico , Neoplasias/imunologia , Rituximab/efeitos adversosRESUMO
The involvement of B cells, complement activation and subsequent immune complex deposition has all been implicated in the pathogenesis of rheumatoid arthritis (RA). Although the reduced expression of complement receptor 1 (CR1, CD35) and 2 (CR2, CD21) on the B cells of RA patients has been known for a long time, their exact role in B-cell tolerance and autoimmunity is not yet fully understood. To get a deeper insight into the possible mechanisms, we studied the expression and function of CR1 and CR2 on various subsets of B cells of healthy donors and RA patients at various stages of the disease by FACS analysis, (3)H-thymidine incorporation and ELISA. We found that CD19(+)CD27(-) naive B cells up-regulate the expression of the inhibitory CR1 during differentiation to CD19(+)CD27(+) memory B cells both in healthy donors and in RA patients, whereas the expression of the activatory CR2 is down-regulated. This clearly demonstrates that the expression of these two antagonistic complement receptors is regulated differentially during the development of human B cells, a phenomenon which may influence the maintenance of peripheral B-cell tolerance. Our functional studies show that after clustering CR1 both by its natural ligand and To5 mAb, the inhibitory function of CD35 is maintained in RA patients, despite its significantly reduced expression compared with healthy individuals. Besides blocking B-cell receptor-induced proliferation, CR1 inhibits the differentiation of B cells to plasmablasts and their immunoglobulin production. Since the reduced expression of CR1 in RA patients does not affect its inhibitory function, this receptor might serve as a new target for therapeutical interventions.
Assuntos
Artrite Reumatoide/imunologia , Linfócitos B/imunologia , Imunidade Humoral , Receptores de Complemento 3b/imunologia , Receptores de Complemento 3d/imunologia , Adulto , Idoso , Antígenos CD19/genética , Antígenos CD19/imunologia , Artrite Reumatoide/patologia , Autoimunidade , Linfócitos B/patologia , Estudos de Casos e Controles , Diferenciação Celular , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Regulação da Expressão Gênica/imunologia , Humanos , Memória Imunológica , Masculino , Pessoa de Meia-Idade , Tolerância Periférica , Receptores de Antígenos de Linfócitos B/genética , Receptores de Antígenos de Linfócitos B/imunologia , Receptores de Complemento 3b/genética , Receptores de Complemento 3d/genética , Transdução de Sinais , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/genética , Membro 7 da Superfamília de Receptores de Fatores de Necrose Tumoral/imunologiaRESUMO
Over two decades ago, an intercropping strategy was developed that received critical acclaim for synergizing food security with ecosystem resilience in smallholder farming. The push-pull strategy reportedly suppresses lepidopteran pests in maize through a combination of a repellent intercrop (push), commonly Desmodium spp., and an attractive, border crop (pull). Key in the system is the intercrop's constitutive release of volatile terpenoids that repel herbivores. However, the earlier described volatile terpenoids were not detectable in the headspace of Desmodium, and only minimally upon herbivory. This was independent of soil type, microbiome composition, and whether collections were made in the laboratory or in the field. Furthermore, in oviposition choice tests in a wind tunnel, maize with or without an odor background of Desmodium was equally attractive for the invasive pest Spodoptera frugiperda. In search of an alternative mechanism, we found that neonate larvae strongly preferred Desmodium over maize. However, their development stagnated and no larva survived. In addition, older larvae were frequently seen impaled and immobilized by the dense network of silica-fortified, non-glandular trichomes. Thus, our data suggest that Desmodium may act through intercepting and decimating dispersing larval offspring rather than adult deterrence. As a hallmark of sustainable pest control, maize-Desmodium push-pull intercropping has inspired countless efforts to emulate stimulo-deterrent diversion in other cropping systems. However, detailed knowledge of the actual mechanisms is required to rationally improve the strategy, and translate the concept to other cropping systems.
Assuntos
Ecossistema , Controle de Pragas , Animais , Agricultura , Larva , Spodoptera , Terpenos , Zea maysRESUMO
Phosphorylation adjacent to nuclear localization signals (NLSs) is involved in the regulation of nucleocytoplasmic transport. The nuclear isoform of human dUTPase, an enzyme that is essential for genomic integrity, has been shown to be phosphorylated on a serine residue (Ser11) in the vicinity of its nuclear localization signal; however, the effect of this phosphorylation is not yet known. To investigate this issue, an integrated set of structural, molecular and cell biological methods were employed. It is shown that NLS-adjacent phosphorylation of dUTPase occurs during the M phase of the cell cycle. Comparison of the cellular distribution of wild-type dUTPase with those of hyperphosphorylation- and hypophosphorylation-mimicking mutants suggests that phosphorylation at Ser11 leads to the exclusion of dUTPase from the nucleus. Isothermal titration microcalorimetry and additional independent biophysical techniques show that the interaction between dUTPase and importin-α, the karyopherin molecule responsible for `classical' NLS binding, is weakened significantly in the case of the S11E hyperphosphorylation-mimicking mutant. The structures of the importin-α-wild-type and the importin-α-hyperphosphorylation-mimicking dUTPase NLS complexes provide structural insights into the molecular details of this regulation. The data indicate that the post-translational modification of dUTPase during the cell cycle may modulate the nuclear availability of this enzyme.
Assuntos
Pirofosfatases/metabolismo , alfa Carioferinas/metabolismo , Transporte Ativo do Núcleo Celular , Ciclo Celular , Cristalografia por Raios X , Células HEK293 , Humanos , Modelos Moleculares , Sinais de Localização Nuclear , Fosforilação , Pirofosfatases/química , alfa Carioferinas/químicaRESUMO
Advances in protein microarray technology allow the generation of high content, reliable information about complex, multilevel protein interaction networks. Yet antigen arrays are used mostly only as devices for parallel immune assays describing multitudes of individual binding events. We propose here that the huge amount of immunological information hidden in the plasma of an individual could be better revealed by combining the characterization of antibody binding to target epitopes with improved estimation of effector functions triggered by these binding events. Furthermore, we could generate functional immune profiles characterizing general immune responsiveness of the individual by designing arrays incorporating epitope collections from diverse subsets of antibody targets.
Assuntos
Antígenos/imunologia , Análise Serial de Proteínas/tendências , Proteínas/imunologia , Anticorpos/imunologia , Antígenos/química , Epitopos/química , Epitopos/imunologia , Epitopos de Linfócito B/química , Epitopos de Linfócito B/imunologia , Humanos , Proteínas/químicaRESUMO
The neonatal FcR (FcRn) regulates IgG and albumin homeostasis, mediates maternal IgG transport, takes active part in phagocytosis, and delivers Ag for presentation. We have previously shown that overexpression of FcRn in transgenic (Tg) mice extends the half-life of mouse IgG by reducing its clearance. In this paper, we demonstrate that immunization of these mice with OVA and trinitrophenyl-conjugated human IgG results in a 3- to 10-fold increase of Ag-specific IgM and IgG in serum. The IgM increase was unexpected because FcRn does not bind IgM. Our results showed that the affinity of the Ag-specific IgG was at least as good in Tg mice as in the wild-type (wt) controls, implying appropriate affinity maturation in both groups. Influenza vaccination produced a 2-fold increase in the amount of virus-specific Ab in Tg animals, which proved twice as efficient in a hemagglutination inhibition assay as was the case in wt controls. After immunization, Tg mice displayed significantly larger spleens containing a higher number of Ag-specific B cells and plasma cells, as well as many more granulocytes and dendritic cells, analyzed by ELISPOT and flow cytometric studies. The neutrophils from these Tg mice expressed the Tg FcRn and phagocytosed IgG immune complexes more efficiently than did those from wt mice. These results show that FcRn overexpression not only extends the IgG half-life but also enhances the expansion of Ag-specific B cells and plasma cells. Although both effects increase the level of Ag-specific IgG, the increase in immune response and IgG production seems to be more prominent compared with the reduced IgG clearance.
Assuntos
Regulação da Expressão Gênica/imunologia , Antígenos de Histocompatibilidade Classe I/biossíntese , Antígenos de Histocompatibilidade Classe I/genética , Imunoglobulina G/biossíntese , Receptores Fc/biossíntese , Receptores Fc/genética , Regulação para Cima/imunologia , Animais , Afinidade de Anticorpos/imunologia , Subpopulações de Linfócitos B/imunologia , Subpopulações de Linfócitos B/metabolismo , Bovinos , Galinhas , Epitopos de Linfócito B/imunologia , Epitopos de Linfócito B/metabolismo , Antígenos de Histocompatibilidade Classe I/fisiologia , Humanos , Imunidade Materno-Adquirida , Imunoglobulina G/metabolismo , Imunoglobulinas/biossíntese , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos , Plasmócitos/imunologia , Plasmócitos/metabolismo , Ligação Proteica/imunologia , Receptores Fc/fisiologia , Regulação para Cima/genéticaRESUMO
BACKGROUND: The cabbage moth, Mamestra brassicae, is a polyphagous pest that attacks several crops. Here, the sublethal and lethal effects of chlorantraniliprole and indoxacarb were investigated on the developmental stages, detoxification enzymes, reproductive activity, calling behavior, peripheral physiology, and pheromone titer of M. brasssicae. Methods: To assess pesticide effects, the second instar larvae were maintained for 24 h on a semi-artificial diet containing insecticides at their LC10, LC30, and LC50 concentrations. RESULTS: M. brassicae was more susceptible to chlorantraniliprole (LC50 = 0.35 mg/L) than indoxacarb (LC50 = 1.71 mg/L). A significantly increased developmental time was observed with both insecticides at all tested concentrations but decreases in pupation rate, pupal weight, and emergence were limited to the LC50 concentration. Reductions in both the total number of eggs laid per female and the egg viability were observed with both insecticides at their LC30 and LC50 concentrations. Both female calling activity and the sex pheromone (Z11-hexadecenyl acetate and hexadecenyl acetate) titer were significantly reduced by chlorantraniliprole in LC50 concentration. Antennal responses of female antennae to benzaldehyde and 3-octanone were significantly weaker than controls after exposure to the indoxocarb LC50 concentration. Significant reductions in the enzymatic activity of glutathione S-transferases, mixed-function oxidases, and carboxylesterases were observed in response to both insecticides.
RESUMO
Although the exact etiology of systemic lupus erythematosus (SLE) remains elusive, B-cell hyperactivity and production of autoantibodies directed to components of the cell nucleus are a well-established pathogenetic mechanism of the disease. Therefore, the targeted inhibition of DNA-specific B cells is a logical therapeutic approach. The complement receptor type 1 (CR1, CD35) has been shown to suppress human B-cell activation and proliferation after co-cross-linking with the BCR, and may serve as a mediator for negative signal delivery. In order to evaluate this therapeutic approach in a human-like system, we used immune-restricted SCID mice transferred with PBMCs from SLE patients. The tolerance of these humanized SCID mice to native DNA was re-established after administration of a chimeric molecule consisting of a CR1-specific mAb coupled to the decapeptide DWEYSVWLSN that mimics dsDNA. The generated protein-engineered chimera was able to co-cross-link selectively native DNA-specific BCR with the B-cell inhibitory receptor CR1, thus delivering a strong inhibitory signal.
Assuntos
Anticorpos Antinucleares/imunologia , Anticorpos Monoclonais/imunologia , Linfócitos B/imunologia , Imunoterapia/métodos , Lúpus Eritematoso Sistêmico/imunologia , Animais , Anticorpos Antinucleares/biossíntese , Anticorpos Antinucleares/uso terapêutico , Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/uso terapêutico , Autoantígenos/imunologia , Autoimunidade/imunologia , Western Blotting , Linhagem Celular , Separação Celular , DNA/imunologia , Modelos Animais de Doenças , Citometria de Fluxo , Humanos , Imunoprecipitação , Ativação Linfocitária/imunologia , Camundongos , Camundongos SCID , Peptídeos , Receptores de Complemento 3b/imunologia , Receptores de Complemento 3b/uso terapêutico , Transdução de Sinais/imunologiaRESUMO
Components of the extracellular matrix (ECM), when exposed to body fluids may promote local complement activation and inflammation. Pathologic complement activation at the glomerular basement membrane and at the Bruch's membrane is implicated in renal and eye diseases, respectively. Binding of soluble complement inhibitors to the ECM, including factor H (FH), is important to prevent excessive complement activation. Since the FH-related (FHR) proteins FHR1 and FHR5 are also implicated in these diseases, our aim was to study whether these FHRs can also bind to ECM components and affect local FH activity and complement activation. Both FH and the FHRs showed variable binding to ECM components. We identified laminin, fibromodulin, osteoadherin and PRELP as ligands of FHR1 and FHR5, and found that FHR1 bound to these ECM components through its C-terminal complement control protein (CCP) domains 4-5, whereas FHR5 bound via its middle region, CCPs 3-7. Aggrecan, biglycan and decorin did not bind FH, FHR1 and FHR5. FHR5 also bound to immobilized C3b, a model of surface-deposited C3b, via CCPs 3-7. By contrast, soluble C3, C3(H2O), and the C3 fragments C3b, iC3b and C3d bound to CCPs 8-9 of FHR5. Properdin, which was previously described to bind via CCPs 1-2 to FHR5, did not bind in its physiologically occurring serum forms in our assays. FHR1 and FHR5 inhibited the binding of FH to the identified ECM proteins in a dose-dependent manner, which resulted in reduced FH cofactor activity. Moreover, both FHR1 and FHR5 enhanced alternative complement pathway activation on immobilized ECM proteins when exposed to human serum, resulting in the increased deposition of C3-fragments, factor B and C5b-9. Thus, our results identify novel ECM ligands of FH family proteins and indicate that FHR1 and FHR5 are competitive inhibitors of FH on ECM and, when bound to these ligands, they may enhance local complement activation and promote inflammation under pathological conditions.
Assuntos
Ativação do Complemento , Proteínas Inativadoras do Complemento C3b , Fator H do Complemento , Proteínas do Sistema Complemento , Proteínas Inativadoras do Complemento C3b/metabolismo , Proteínas do Sistema Complemento/metabolismo , Matriz Extracelular , Humanos , Inflamação , LigantesRESUMO
I met Bob in 1985, when I moved with my family to Oxford for a two-year EMBO fellowship at the MRC Immunochemistry Unit [...].