RESUMO
The pneumococcal whole cell vaccine (PWCV) has been investigated as an alternative to polysaccharide-based vaccines currently in use. It is a non-encapsulated killed vaccine preparation that induces non-capsular antibodies protecting mice against invasive pneumococcal disease (IPD) and reducing nasopharyngeal (NP) carriage via IL-17A activation of mouse phagocytes. Here, we show that PWCV induces antibody and IL-17A production to protect mice against challenge in a fatal aspiration-sepsis model after only one dose. We observed protection even with a boiled preparation, attesting to the stability and robustness of the vaccine. PWCV antibodies were shown to bind to different encapsulated strains, but complement deposition on the pneumococcal surface was observed only on serotype 3 strains; using flow cytometer methodology, variations in PWCV quality, as in the boiled vaccine, were detected. Moreover, anti-PWCV induces phagocytosis of different pneumococcal serotypes by murine peritoneal cells in the presence of complement or IL-17A. These findings suggest that complement and IL-17A may participate in the process of phagocytosis induced by PWCV antibodies. IL-17A can stimulate phagocytic cells to kill pneumococcus and this is enhanced in the presence of PWCV antibodies bound to the bacterial cell surface. Our results provide further support for the PWCV as a broad-range vaccine against all existing serotypes, potentially providing protection for humans against NP colonization and IPD. Additionally, we suggest complement deposition assay as a tool to detect subtle differences between PWCV lots.
Assuntos
Complemento C3/imunologia , Interleucina-17/imunologia , Infecções Pneumocócicas/imunologia , Infecções Pneumocócicas/prevenção & controle , Vacinas Pneumocócicas/imunologia , Streptococcus pneumoniae/imunologia , Animais , Sítios de Ligação de Anticorpos , Citometria de Fluxo , Camundongos , Nasofaringe/microbiologia , Proteínas Opsonizantes/imunologia , Fagocitose , Vacinas Pneumocócicas/administração & dosagem , Sepse/imunologia , Sepse/microbiologia , Sepse/prevenção & controle , Sorogrupo , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologiaRESUMO
Brucella abortus is an intracellular pathogen of monocytes, macrophages, dendritic cells, and placental trophoblasts. This bacterium causes a chronic disease in bovines and in humans. In these hosts, the bacterium also invades neutrophils; however, it fails to replicate and just resists the killing action of these leukocytes without inducing significant activation or neutrophilia. Moreover, B. abortus causes the premature cell death of human neutrophils. In the murine model, the bacterium is found within macrophages and dendritic cells at early times of infection but seldom in neutrophils. Based on this observation, we explored the interaction of mouse neutrophils with B. abortus In contrast to human, dog, and bovine neutrophils, naive mouse neutrophils fail to recognize smooth B. abortus bacteria at early stages of infection. Murine normal serum components do not opsonize smooth Brucella strains, and neutrophil phagocytosis is achieved only after the appearance of antibodies. Alternatively, mouse normal serum is capable of opsonizing rough Brucella mutants. Despite this, neutrophils still fail to kill Brucella, and the bacterium induces cell death of murine leukocytes. In addition, mouse serum does not opsonize Yersinia enterocolitica O:9, a bacterium displaying the same surface polysaccharide antigen as smooth B. abortus Therefore, the lack of murine serum opsonization and absence of murine neutrophil recognition are specific, and the molecules responsible for the Brucella camouflage are N-formyl-perosamine surface homopolysaccharides. Although the mouse is a valuable model for understanding the immunobiology of brucellosis, direct extrapolation from one animal system to another has to be undertaken with caution.
Assuntos
Brucella abortus/imunologia , Evasão da Resposta Imune , Manose/imunologia , Neutrófilos/microbiologia , Fagocitose , Polissacarídeos Bacterianos/imunologia , Animais , Brucella abortus/crescimento & desenvolvimento , Sequência de Carboidratos , Bovinos , Morte Celular , Cães , Expressão Gênica , Especificidade de Hospedeiro , Humanos , Imunidade Humoral , Imunidade Inata , Manose/análogos & derivados , Camundongos , Neutrófilos/imunologia , Proteínas Opsonizantes/genética , Proteínas Opsonizantes/imunologia , Polissacarídeos Bacterianos/química , Yersinia enterocolitica/crescimento & desenvolvimento , Yersinia enterocolitica/imunologiaRESUMO
Bordetella parapertussis is a human pathogen that causes whooping cough. The increasing incidence of B. parapertussis has been attributed to the lack of cross protection induced by pertussis vaccines. It was previously shown that B. parapertussis is able to avoid bacterial killing by polymorphonuclear leukocytes (PMN) if specific opsonic antibodies are not present at the site of interaction. Here, we evaluated the outcome of B. parapertussis innate interaction with human macrophages, a less aggressive type of cell and a known reservoir of many persistent pathogens. The results showed that in the absence of opsonins, O antigen allows B. parapertussis to inhibit phagolysosomal fusion and to remain alive inside macrophages. The O antigen targets B. parapertussis to lipid rafts that are retained in the membrane of phagosomes that do not undergo lysosomal maturation. Forty-eight hours after infection, wild-type B. parapertussis bacteria but not the O antigen-deficient mutants were found colocalizing with lipid rafts and alive in nonacidic compartments. Taken together, our data suggest that in the absence of opsonic antibodies, B. parapertussis survives inside macrophages by preventing phagolysosomal maturation in a lipid raft- and O antigen-dependent manner. Two days after infection, about 15% of macrophages were found loaded with live bacteria inside flotillin-enriched phagosomes that had access to nutrients provided by the host cell recycling pathway, suggesting the development of an intracellular infection. IgG opsonization drastically changed this interaction, inducing efficient bacterial killing. These results highlight the need for B. parapertussis opsonic antibodies to induce bacterial clearance and prevent the eventual establishment of cellular reservoirs of this pathogen.
Assuntos
Bordetella parapertussis/fisiologia , Macrófagos/química , Macrófagos/microbiologia , Microdomínios da Membrana , Viabilidade Microbiana , Fagossomos/química , Fagossomos/microbiologia , Anticorpos Antibacterianos/imunologia , Bordetella parapertussis/imunologia , Bordetella parapertussis/isolamento & purificação , Células Cultivadas , Humanos , Macrófagos/imunologia , Antígenos O/metabolismo , Proteínas Opsonizantes/imunologiaRESUMO
BACKGROUND: Seven-valent pneumococcal conjugate vaccine (PCV7) has reduced incidence of vaccine-serotype pneumococcal diseases. Using a single dose of 13-valent pneumoccal conjugate vaccine (PCV13), we evaluated late immune responses 10 years after vaccination with PCV7 in infancy, compared with a PCV7-naïve cohort. METHODS: In this open-label study, we administered 1 dose of PCV13 to children aged 11-14 years who had previously received PCV7 (PCV7/PCV13) or meningococcal group C conjugate vaccine (MnCC/PCV13) during infancy. We evaluated serotype-specific immunoglobulin G concentrations and opsonophagocytic activity prevaccination and 1 week and 1 month postvaccination. We recorded local reactions and systemic events for 4 days postvaccination and adverse events for 6 months. RESULTS: Seventy-four subjects received PCV13 (PCV7/PCV13, n = 38; MnCC/PCV13, n = 36). Prevaccination with PCV13, >62.9% of subjects had immunoglobulin G concentrations ≥0.35 µg/mL for all serotypes except serotype 4 (28-29%); proportions increased at 1 month postvaccination to 100% for all serotypes except serotypes 3 (PCV7/PCV13, 94.7%; MnCC/PCV13, 97.0%) and 14 (MnCC/PCV13, 97.1%). Immunoglobulin G and opsonophagocytic activity concentrations for the 7 common and 6 additional serotypes were similar in both groups prevaccination and increased in both groups from prevaccination to 1 week and 1 month postvaccination. Local reactions and fever were mild or moderate; no serious adverse events were reported. CONCLUSION: Late immune responses after a single dose of PCV13 were similar in children aged 11-14 years regardless of previous vaccination with PCV7 or MnCC. PCV13 was immunogenic, safe and well tolerated.
Assuntos
Vacinas Pneumocócicas/administração & dosagem , Vacinas Pneumocócicas/imunologia , Adolescente , Anticorpos Antibacterianos/sangue , Criança , Efeitos Colaterais e Reações Adversas Relacionados a Medicamentos/epidemiologia , Feminino , Vacina Pneumocócica Conjugada Heptavalente , Humanos , Imunoglobulina G/sangue , Masculino , Proteínas Opsonizantes/imunologia , Fagocitose , Fatores de Tempo , Vacinas Conjugadas/administração & dosagem , Vacinas Conjugadas/imunologiaRESUMO
Bordetella pertussis is the etiologic agent of whooping cough, an illness whose incidence has been increasing over the last decades. Pertussis reemergence despite high vaccination coverage, together with the recent isolation of circulating strains deficient in some of the vaccine antigens, highlight the need for new vaccines. Proteins induced under physiological conditions, such as those required for nutrient acquisition during infection, might represent good targets for better preventive strategies. By mean of serological proteome analysis we identified two novel antigens of B. pertussis potentially involved in iron acquisition during host colonization. We had previously demonstrated that one of them, designated IRP1-3, is protective against pertussis infection in mice. In the present study, we show that the other antigen, named AfuA (BP1605), is a highly antigenic protein, exposed on the bacterial surface, conserved among clinical isolates and expressed during infection. Immunization of mice with the recombinant AfuA induced opsonophagocytic antibodies which could explain the protection against B. pertussis infection conferred by mice immunization with rAfuA. Importantly, we found that the addition of rAfuA and rIRP1-3 proteins to the commercial three pertussis components acellular vaccine significantly increased its protective activity. Taken together, our results point at these two antigens as potential components of a new generation of acellular vaccines.
Assuntos
Antígenos de Bactérias/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Bordetella pertussis/imunologia , Proteína 1 Reguladora do Ferro/imunologia , Vacina contra Coqueluche/imunologia , Coqueluche/imunologia , Animais , Anticorpos Antibacterianos/sangue , Células Cultivadas , Feminino , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Neutrófilos , Proteínas Opsonizantes/imunologia , Vacina contra Coqueluche/química , Vacinação , Coqueluche/microbiologia , Coqueluche/prevenção & controleRESUMO
Sporothrix schenckii is a human pathogen that causes sporotrichosis, a cutaneous subacute or chronic mycosis. Little is known about the innate immune response and the receptors involved in host recognition and phagocytosis of S. schenckii. Here, we demonstrate that optimal phagocytosis of conidia and yeast is dependent on preimmune human serum opsonisation. THP-1 macrophages efficiently ingested opsonised conidia. Competition with D-mannose, methyl α-D-mannopyranoside, D-fucose, and N-acetyl glucosamine blocked this process, suggesting the involvement of the mannose receptor in binding and phagocytosis of opsonised conidia. Release of TNF-α was not stimulated by opsonised or non-opsonised conidia, although reactive oxygen species (ROS) were produced, resulting in the killing of conidia by THP-1 macrophages. Heat inactivation of the serum did not affect conidia internalization, which was markedly decreased for yeast cells, suggesting the role of complement components in yeast uptake. Conversely, release of TNF-α and production of ROS were induced by opsonised and non-opsonised yeast. These data demonstrate that THP-1 macrophages respond to opsonised conidia and yeast through different phagocytic receptors, inducing a differential cellular response. Conidia induces a poor pro-inflammatory response and lower rate of ROS-induced cell death, thereby enhancing the pathogen's survival.
Assuntos
Macrófagos/imunologia , Fagocitose , Sporothrix/citologia , Sporothrix/imunologia , Linhagem Celular , Proteínas do Sistema Complemento/imunologia , Humanos , Lectinas Tipo C/metabolismo , Receptor de Manose , Lectinas de Ligação a Manose/metabolismo , Proteínas Opsonizantes/imunologia , Espécies Reativas de Oxigênio/metabolismo , Receptores de Superfície Celular/metabolismo , Esporos Fúngicos/imunologia , Fator de Necrose Tumoral alfa/metabolismoRESUMO
The goal of the study was to determine baseline protective titers of antibodies to Streptococcus pneumoniae surface protein A (PspA) and capsular polysaccharide in individuals with and individuals without type 2 diabetes mellitus. A total of 561 individuals (131 individuals with diabetes and 491 without) were screened for antibodies to PspA using a standard enzyme-linked immunosorbent assay (ELISA). A subset of participants with antibodies to PspA were retested using a WHO ELISA to determine titers of antibodies to capsular polysaccharide (CPS) (serotypes 4, 6B, 9V, 14, 18C, 19A, 19F, and 23F). Functional activity of antibodies was measured by assessing their ability to enhance complement (C3) deposition on pneumococci and promote killing of opsonized pneumococci. Titers of antibodies to protein antigens (PspA) were significantly lower in individuals with diabetes than controls without diabetes (P = 0.01), and antibodies showed a significantly reduced complement deposition ability (P = 0.02). Both antibody titers and complement deposition were negatively associated with hyperglycemia. Conversely, titers of antibodies to capsular polysaccharides were either comparable between the two groups or were significantly higher in individuals with diabetes, as was observed for CPS 14 (P = 0.05). The plasma specimens from individuals with diabetes also demonstrated a higher opsonophagocytic index against CPS serotype 14. Although we demonstrate comparable protective titers of antibodies to CPS in individuals with and individuals without diabetes, those with diabetes had lower PspA titers and poor opsonic activity strongly associated with hyperglycemia. These results suggest a link between diabetes and impairment of antibody response.
Assuntos
Anticorpos Antibacterianos/sangue , Proteínas de Bactérias/imunologia , Diabetes Mellitus Tipo 2/imunologia , Polissacarídeos Bacterianos/imunologia , Streptococcus pneumoniae/imunologia , Adulto , Atividade Bactericida do Sangue , Proteínas do Sistema Complemento/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Masculino , Americanos Mexicanos , Pessoa de Meia-Idade , Proteínas Opsonizantes/imunologiaRESUMO
Foot and Mouth Disease (FMD) is an acute disease of cloven-hoofed species. We studied the protection and early immune response induced in the murine model by vaccines formulated with inactivated virus and two different adjuvants. The presence of IMS12802PR or ISA206VG adjuvants yielded protection against viral challenge at early times post vaccination and induced FMDV-specific, but non neutralizing, antibody titers. In vivo macrophage depletion in vaccinated mice severely decreased the protection levels after virus challenge, indicating a central role of this cell population in the response elicited by the vaccines. Accordingly, opsonophagocytosis of FITC-labelled virus was augmented in 802-FMDVi and 206-FMDVi vaccinated mice. These results demonstrate the ability of the studied adjuvants to enhance the protective responses of these inactivated vaccines without the increase in seroneutralizing antibodies and the main role of opsonization and phagocytosis in the early protective immune responses against FMD infection in the murine model.
Assuntos
Febre Aftosa/imunologia , Febre Aftosa/prevenção & controle , Macrófagos/imunologia , Vacinas Virais/administração & dosagem , Vacinas Virais/imunologia , Adjuvantes Imunológicos/administração & dosagem , Animais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , Procedimentos de Redução de Leucócitos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Proteínas Opsonizantes/imunologia , Fagocitose/imunologia , Vacinas de Produtos Inativados/administração & dosagem , Vacinas de Produtos Inativados/imunologiaRESUMO
BACKGROUND: Several elements in colostrum and human milk, including antibodies and nonspecific factors with bactericidal and antiviral activity, may play an important anti-infectious and protective role. In developing countries, enterotoxigenic Escherichia coli (ETEC) is the main etiological agent of diarrhea in low-socioeconomic level children. In the present work, we studied the functional activity of mononuclear (MN) and polymorphonuclear (PMN) phagocytes of human colostrum against ETEC, as well as the interactions between these cells and colostral or serum opsonins. METHODS: Colostrum samples were collected from 33 clinically healthy women between 48 and 72 hours postpartum. We verified superoxide release in colostral MN and PMN using cytochrome C reduction methods, phagocytosis, and bactericidal activity using acridine orange methods and superoxide dismutase (SOD) in the colostrum supernatants. RESULTS: Colostral MN and PMN phagocytes exposed to ETEC opsonized with colostrum supernatants caused a significant increase (p<0.05) in superoxide release. Phagocytosis by colostral PMN cells increased significantly (p<0.5) when the phagocytes were incubated with both sources of opsonins (sera and colostrum). Increases in superoxide release in the presence of opsonized bacteria triggered the bactericidal activity of the phagocytes. Phagocyte treatment with SOD decreased their ability to eliminate ETEC. Colostrum supernatant had higher SOD concentrations (p<0.05) compared with normal human sera. CONCLUSIONS: These results suggest that the ability of phagocytes to eliminate ETEC depends on the activation of cellular oxidative metabolism; moreover, activation of colostral phagocytes is likely an additional breast-feeding protection mechanism against intestinal infections in infants.
Assuntos
Colostro/imunologia , Escherichia coli Enterotoxigênica/imunologia , Proteínas Opsonizantes/imunologia , Fagócitos/imunologia , Fagocitose , Adolescente , Adulto , Feminino , Humanos , Viabilidade Microbiana , Superóxido Dismutase/análise , Superóxidos/análise , Adulto JovemRESUMO
Se obtuvo suero antiglobulínico (Coombs) con el empleo de un inóculo consistente en un inmunocomplejo (IC) inmunoglobulina (Ig) humana-antiglobulina humana en carnero, como opsonina para favorecer la respuesta inmune. Se inmunizaron 18 carneros divididos en 3 grupos de 6: el primero y el segundo destinados a producir anti-IgG y anti-C3, respectivamente. Estos, a su vez, subdivididos en subgrupo A: en el que se empleó el método tradicional de obtención de suero de Coombs; y B: en el que se usó el adyuvante completo de Freud en la dosis inicial y el IC en la fase de mantenimiento. Al tercer grupo solo se le administró el IC puro (subgrupo A) y en una dilución 1:200 (subgrupo B). En los carneros de los subgrupos 1B y 2B se obtuvieron títulos más elevados de anti-IgG y anti-C3dg, que en los inmunizados por el método tradicional. La respuesta de anticuerpos en los animales que se inmunizaron con los IC (3A y 3B), fue más rápida y de mayor título que las obtenidas por el método tradicional (1A y 2A) o el método combinado (1B y 2B). La respuesta en el subgrupo 3B fue más prolongada, al parecer por un efecto de dosis
An antiglobulin serum (Coombs) was obtained using a consistent inoculums in a immunocomplex (IC) the human immunoglobulin (Ig)/human antiglobulin in the seep by example, the opsonin to favor the immune response. Eighteen sheeps were immunized divided into three groups of 6 each: The first and second aimed to produce anti-IgG and anti-C3, respectively. In turn, these were divided into the A subgroup: in which we used the traditional method of Coombs's serum obtaining and B group in which we used the Freud's whole adjuvant in initial dose and the IC in the maintaining phase. Third group received the pure IC (A subgroup) and at a dilution of 1:200 (B subgroup). In sheeps from the 1B and 2B subgroups it was possible to obtain higher titration of anti-IgG and anti-C3dg than those immunized by means of the traditional method. The antibody response in animals immunized with the ICs (3A and 3B) was faster and of higher titration than those obtained by traditional method (1A and 2A) or the combined method (1B and 2B). The response in the 3B subgroup was lengthier apparently by a dose effect
Assuntos
Animais , Adjuvante de Freund , Imunoglobulinas , Proteínas Opsonizantes/imunologia , Teste de Coombs/métodos , Soros Imunes , Ovinos/imunologia , Ovinos/sangueRESUMO
Bordetella pertussis-specific antibodies protect against whooping cough by facilitating host defense mechanisms such as phagocytosis. However, the mechanism involved in the phagocytosis of the bacteria under non-opsonic conditions is still poorly characterized. We report here that B. pertussis binding and internalization is cholesterol dependent. Furthermore, we found cholesterol to be implicated in B. pertussis survival upon interaction with human neutrophils. Pre-treatment of PMN with cholesterol sequestering drugs like nystatin or methyl-beta-cyclodextrin (MbetaCD) resulted in a drastic decrease of uptake of non-opsonized B. pertussis. Conversely, phagocytosis of opsonized bacteria was not affected by these drugs, showing that cholesterol depletion affects neither the viability of PMN nor the route of entry of opsonized B. pertussis. Additionally, intracellular survival rate of non-opsonized bacteria was significantly decreased in cholesterol-depleted PMN. Accordingly, confocal laser microscopy studies showed that non-opsonized B. pertussis co-localized with lysosomal markers only in cholesterol-depleted PMN but not in normal PMN. Our results indicate that B. pertussis docks to molecules that eventually prevent cellular bactericidal activity.
Assuntos
Infecções por Bordetella/microbiologia , Bordetella pertussis/fisiologia , Colesterol/metabolismo , Viabilidade Microbiana , Neutrófilos/química , Neutrófilos/microbiologia , Fagocitose , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Aderência Bacteriana/efeitos dos fármacos , Infecções por Bordetella/imunologia , Bordetella pertussis/imunologia , Membrana Celular/química , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Colesterol/química , Humanos , Neutrófilos/imunologia , Neutrófilos/fisiologia , Nistatina/farmacologia , Proteínas Opsonizantes/sangue , Proteínas Opsonizantes/imunologia , Fagocitose/efeitos dos fármacos , Estrutura Terciária de Proteína , beta-Ciclodextrinas/farmacologiaRESUMO
In their mammalian hosts, Leishmania are obligate intracellular parasites that reside in macrophages and dendritic cells (DCs). In the present study, we have investigated in vitro the mechanisms of entry into human DCs of Leishmania amazonensis amastigotes isolated from lesions in nude mice (Am nude). The DC infection rate with Am nude was approximately 36%, while opsonization of Am nude with normal human serum and infected human serum increased the DC infection rates to 60% and 62%, respectively. Heat inactivation and depletion of antibodies in sera brought the DC infection rate down to 40%. The DC infection rate was inhibited after pre-treatment of Am nude with heparin. We were unable to implicate mannose-fucose receptors in the uptake of Am nude by DCs. Our data suggest that the ability of L. amazonensis amastigotes to infect human DCs involves the participation of at least three multiple receptor-ligand interactions, antibodies/FcR, complement components/CR and proteoglycans/heparin-binding protein.
Assuntos
Células Dendríticas/parasitologia , Heparitina Sulfato/metabolismo , Lectinas Tipo C/metabolismo , Leishmania mexicana/fisiologia , Mananas/metabolismo , Lectinas de Ligação a Manose/metabolismo , Receptores de Superfície Celular/metabolismo , Receptores Fc/metabolismo , Animais , Anticorpos Antiprotozoários/imunologia , Moléculas de Adesão Celular/metabolismo , Células Cultivadas , Proteínas do Sistema Complemento/metabolismo , Humanos , Soros Imunes/imunologia , Leishmania mexicana/imunologia , Ligantes , Receptor de Manose , Camundongos , Camundongos Endogâmicos C3H , Camundongos Nus , Proteínas Opsonizantes/imunologia , Proteoglicanas/metabolismo , Receptores de Complemento/metabolismoRESUMO
BACKGROUND: Giardia lamblia is an important cause of parasitic diarrheal disease worldwide. Occasionally, polymorphonuclear neutrophils (PMNs) may participate as effector cells against Giardia lamblia. The present study was performed in order to examine the role of specific antibody and complement components in promoting the respiratory burst (RB) of PMNs against Giardia lamblia. METHODS: PMNs from human adult volunteers were incubated with Giardia trophozoites in the presence of non-immune (NS) or hyperimmune (HS) serum (anti-Giardia titer, >1:1024). Adherence was scored visually on coverslide after staining with Giemsa. The ability of Giardia to trigger the oxidative response of PMNs was measured by the anion superoxide (O2(-)) production using a cytochrome C reduction method and by the luminol amplified chemiluminescence (CL) assay. RESULTS: Incubation with NS or HS increased Giardia adherence to PMNs from 6.9 +/- 3.2% (basal adherence of Giardia incubated in buffer) to 39 +/- 18.6% (p <0.01) and 76 +/- 19.5% (p <0.001), respectively. In absence of serum, Giardia failed to trigger an oxidative response of PMNs. Opsonization with NS or HS increased the PMN O2(-) production from 3.9 +/- 0.92 nmol/2.5 x 10(6) PMNs/10 min to 9.04 +/- 1.68 (p <0.05) and 17.9 +/- 1.32 (p <0.001), respectively. A similar enhancement of the CL response was also observed. The inactivation of complement activity by heat as well as the elimination of specific antibodies by absorption produced a significant abrogation of the oxidative response but in the case of HS heat inactivation alone did not abolish the response. Similar findings (variable abrogation of the oxidative PMN response) were observed when PMNs were incubated with monoclonal antibodies directed against complement C3, C3b or the low-affinity Fc receptors (CR1, CR3 or FcRlo). CONCLUSIONS: These results show that complement components and specific antibodies influence in the Giardia-PMN interaction. Although components of complement can contribute to the RB of PMNs, specific antibodies are critical for an optimal oxidative PMN response.
Assuntos
Giardia lamblia/crescimento & desenvolvimento , Giardia lamblia/imunologia , Neutrófilos/imunologia , Proteínas Opsonizantes/imunologia , Explosão Respiratória , Animais , Anticorpos Monoclonais/imunologia , Adesão Celular , Humanos , Neutrófilos/citologia , Neutrófilos/metabolismo , Receptores Imunológicos/imunologia , Superóxido Dismutase/metabolismo , Superóxidos/metabolismoRESUMO
Though the armadillo is important as a research model in leprosy studies, the activity of armadillo's neutrophils is an aspect of little research. The aim of this study was carried out to partially characterize the chemotaxis, endocytosis and bacteriocidal ability of the neutrophils found in the nine-banded armadillo (Dasypus novemcinctus). Results showed that the chemotactic activity of the neutrophils, evaluated by the movement of the neutrophils through a nitrocellulose membrane (5 microm) in response to a chemo-attractive substance, was greater towards the armadillo serum (5.16+/-1.35 migration index, p<0.05) than towards the formil methionyl leucil phenylalanine (fMLP, 1.43+/-0.18 migration index) or human serum (0.56+/-0.18 migration index). Regarding endocytic capacity of the neutrophils and the monocytes against Escherichia coli was evaluated by a flow cytometry and using opsonized and non-opsonized E. coli-FITC at the following incubation times: 5, 10, 20, 30 and 60 min. The largest percentage of endocytosis by the neutrophils was 92.32+/-0.12% with opsonized bacteria and 77.73+/-14.33% with non-opsonized bacteria at 10 min incubation time, while the largest percentage of endocytosis by monocytes was 89.94+/-1.40% with opsonized bacteria and 73.07+/-15.6% with non-opsonized bacteria at 20 min incubation time. Evaluation of the bacteriocidal capacity of neutrophils using the methyl-thiazol-tetrazolium salts (MTT) reduction color-measurement assay showed an 89.0+/-10% mortality rate of non-opsonized E. coli and 89.0+10% of opsonized E. coli. In conclusion, the armadillo neutrophils show a good phagocytosis and bacteriocidal activity; however, a deficiency in the migration towards the fMLP was observed. This deficiency could be a cause so that the armadillo neutrophils do not respond quickly to invading microorganism.
Assuntos
Tatus/imunologia , Neutrófilos/imunologia , Fagocitose , Animais , Atividade Bactericida do Sangue , Quimiotaxia de Leucócito/efeitos dos fármacos , Endocitose , Escherichia coli/imunologia , Humanos , Técnicas In Vitro , Cinética , Hanseníase/imunologia , Monócitos/imunologia , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Neutrófilos/efeitos dos fármacos , Proteínas Opsonizantes/imunologiaRESUMO
Staphylococcus aureus is a pathogen that has been associated with nosocomial infections since the preantibiotic era. Since the introduction of antibiotics in medical practice in the 1940 s, methicillin-resistant S. aureus (MRSA) strains have been emerging in various parts of the world. In view of the important role of the phagocytic system in the defense against this bacteria, we decided to study phagocytosis by neutrophils and monocytes of an epidemic MRSA strain in São Paulo, Brazil, in comparison with methicillin-sensitive strains. Complement system opsonins are fundamental for efficient ingestion of the resistant and sensitive strains by both types of phagocytes. We found no association of the opsonic requirement of the MRSA strain with the multiresistance phenotype. On the other hand, the MRSA strain was found to be more resistant to the effector mechanisms of neutrophils than both sensitive strains when opsonized with fresh serum, despite the phagocytosis results. This fact suggests that the intracellular killing of S. aureus is an additional parameter of bacterial virulence, but new approaches must be implemented to study the interactions of this MRSA strain with phagocytes in order to investigate the possible factors involved in its behavior in response to neutrophil effector mechanisms.
Assuntos
Resistência a Meticilina/imunologia , Monócitos/imunologia , Neutrófilos/imunologia , Fagocitose/imunologia , Staphylococcus aureus/imunologia , Adolescente , Adulto , Humanos , Imunoglobulinas/imunologia , Masculino , Pessoa de Meia-Idade , Proteínas Opsonizantes/imunologia , Proteína C/imunologia , Staphylococcus aureus/efeitos dos fármacosRESUMO
Colostrum plays an important role in protecting newborn infants against acute gastrointestinal and respiratory infections. IgA antibodies have been considered the major effector component; however, the role of their receptors on colostral phagocytes, especially neutrophils, has not been studied. Here, we demonstrate that CD15+ colostrum neutrophils express IgA Fc receptors (Fc alphaR, CD89) at levels similar to those of blood neutrophils. Most colostral cells (70%) bear secretory IgA (SIgA) on their surface (and intracellularly), whereas blood cells do not. The Fc alphaR on colostral neutrophils was identified as the a.1 isoform with a similar molecular mass (55-75 kDa) as that identified for blood neutrophils. Removal of N-linked carbohydrates revealed a major protein core of 32 kDa for both cell types. In contrast, co-immunoprecipitation and immunoblot experiments using a mild detergent, digitonin, revealed a lack of gamma chain association with Fc alphaR (gamma-less) exclusively on colostral neutrophils. The functional role of these gamma-less Fc alphaR cells was evaluated by measuring superoxide release and killing of SIgA-coated enteropathogenic E. coli. No increase in superoxide release was observed in colostral cells compared with blood neutrophils, whereas optimal release was obtained with PMA stimulation. Furthermore, despite similar bacterial phagocytosis index between both cell types, IgA-mediated bacterial-killing was not detectable with colostral neutrophils, whereas killing was detectable on blood cells. These results reveal exclusive expression of gamma-less Fc alphaR on colostral neutrophils associated with receptor hyperoccupation by IgA and with low, bacterial-killing activity, which suggest that this receptor may mediate noninflammatory effects of SIgA.
Assuntos
Antígenos CD/biossíntese , Colostro/imunologia , Colostro/metabolismo , Imunoglobulina A Secretora/metabolismo , Imunoglobulina A/metabolismo , Neutrófilos/imunologia , Neutrófilos/metabolismo , Receptores Fc/biossíntese , Adolescente , Adulto , Antígenos CD/sangue , Atividade Bactericida do Sangue/imunologia , Pré-Escolar , Colostro/citologia , Colostro/microbiologia , Endocitose/imunologia , Escherichia coli/imunologia , Escherichia coli/patogenicidade , Feminino , Humanos , Imunoglobulina A/sangue , Lactente , Inflamação/imunologia , Inflamação/metabolismo , Neutrófilos/microbiologia , Proteínas Opsonizantes/imunologia , Fagocitose/imunologia , Isoformas de Proteínas/biossíntese , Receptores de Antígenos de Linfócitos B/metabolismo , Receptores Fc/sangue , Superóxidos/metabolismoRESUMO
Immunity to group A streptococci (GAS) is thought to be related to the acquisition of type-specific antibody directed against the M protein. However, recent work suggests that immunity may only be strain and not M-type specific. Therefore, susceptibility of 70 different GAS M-1 strains to opsonization and killing by convalescent sera was compared by using a highly sensitive chemiluminescence assay and by standard bactericidal assay. Sequencing of the emm1 gene in 10 strains with variable susceptibility to opsonization revealed 100% homology in 9 strains. Several substitutions in the N-terminal and 2 in the A3 repeat regions of strain CS-190 were associated with profound resistance to opsonization. Thus amino acid substitutions within different regions of the M-1 protein molecule may adversely affect opsonization by immune sera. In addition, non-M protein factors from identical M types influence susceptibility to phagocytosis. These findings may in part explain the persistently high prevalence of M-1 strains worldwide over the last 15 years.
Assuntos
Antígenos de Bactérias , Proteínas da Membrana Bacteriana Externa , Proteínas de Bactérias/imunologia , Proteínas de Transporte/imunologia , Soros Imunes/imunologia , Proteínas Opsonizantes/imunologia , Fagocitose/imunologia , Streptococcus pyogenes/imunologia , Sequência de Aminoácidos , Substituição de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Atividade Bactericida do Sangue , Proteínas de Transporte/química , Proteínas de Transporte/genética , Proteínas do Sistema Complemento/imunologia , Humanos , Medições Luminescentes , Dados de Sequência Molecular , Análise de Sequência de DNA , Sorotipagem , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/classificaçãoRESUMO
Objetivo: El presente trabajo hace una breve revisión de la escasa literatura existente sobre el papel que desempeñan los receptores Fcç participan en la fagocitosis de levaduras del hongo Histoplasma capsulatum por fagocitos humanos y murinos. Conclusiones: Resultados de diferentes ensayos sugieren que los receptores Fcç participan en la etapa de internalización, aunque parecen no ser los receptores preferenciales para la entrada del hongo a las células fagocíticas murinas
Assuntos
Humanos , Animais , Histoplasma/imunologia , Histoplasma/isolamento & purificação , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Proteínas Opsonizantes/imunologia , Fagocitose/imunologia , Leveduras/classificação , Leveduras/isolamento & purificaçãoAssuntos
Humanos , Complexo Antígeno-Anticorpo , Proteínas do Sistema Complemento/imunologia , Ativação do Complemento/fisiologia , Complemento C1s/ultraestrutura , Convertases de Complemento C3-C5/biossíntese , Complexo de Ataque à Membrana do Sistema Complemento/imunologia , Proteínas Opsonizantes/imunologia , Properdina/fisiologiaRESUMO
Se da cuenta de un método rápido para la cuantización del flujo citométrico de la fagocitosis en sangre periférica completamente heparinizada (HCPB), mediante la utilización de partículas de látex phycoerythrin-conjugadas de 1µm de diámetro disponibles comercialmente. El método es más rápido y presenta mayor reproducibilidad que la técnica estandar de Bjerknes' (1984) utilizando propidium iodide-teñida Candida albicans, aplicada convencionalmente a la capa leucocitica de sangre periférica pero modificada por HCPB. Tambien damos cuenta de una modificación de Bjerknes' Intracellular Killing Test para permitir su aplicación a HCPB.
We report a rapid method for the flow cytometric quantitation of phagocytosis in heparinized complete peripheral blood (HCPB), using commercially available phycoerythrin-conjugated latex particles of 1 micron diameter. The method is faster and shows greater reproducibility than Bjerknes' (1984) standard technique using propidium iodide-stained Candida albicans, conventionally applied to the leukocytic layer of peripheral blood but here modified for HCPB. We also report a modification of Bjerknes' Intracellular Killing Test to allow its application to HCPB.