RESUMO
Bacterial ABC importers catalyze the uptake of essential nutrients including transition metals and metal-containing co-factors. Recently, an IgG antibody targeting the external binding protein of the Staphylococcus aureus Mn(II) ABC importer was reported to inhibit transport activity and reduce bacterial cell growth. We here explored the possibility of using alpaca-derived nanobodies to inhibit the vitamin B12 transporter of Escherichia coli, BtuCD-F, as a model system by generating nanobodies against the periplasmic binding protein BtuF. We isolated six nanobodies that competed with B12 for binding to BtuF, with inhibition constants between 10-6 and 10-9 M. Kinetic characterization of the nanobody-BtuF interactions revealed dissociation half-lives between 1.6 and 6 minutes and fast association rates between 104 and 106 M-1s-1. For the tightest-binding nanobody, we observed a reduction of in vitro transport activity of BtuCD-F when an excess of nanobody over B12 was used. The structure of BtuF in complex with the most effective nanobody Nb9 revealed the molecular basis of its inhibitory function. The CDR3 loop of Nb9 reached into the substrate-binding pocket of BtuF, preventing both B12 binding and BtuCD-F complex formation. Our results suggest that nanobodies can mediate ABC importer inhibition, providing an opportunity for novel antibiotic strategies.
Assuntos
Transportadores de Cassetes de Ligação de ATP/antagonistas & inibidores , Transporte Biológico/efeitos dos fármacos , Proteínas de Escherichia coli/antagonistas & inibidores , Proteínas de Escherichia coli/metabolismo , Escherichia coli/crescimento & desenvolvimento , Proteínas Periplásmicas de Ligação/antagonistas & inibidores , Proteínas Periplásmicas de Ligação/metabolismo , Anticorpos de Domínio Único/imunologia , Vitamina B 12/metabolismo , Transportadores de Cassetes de Ligação de ATP/imunologia , Transportadores de Cassetes de Ligação de ATP/metabolismo , Animais , Camelídeos Americanos/imunologia , Cristalografia por Raios X , Escherichia coli/imunologia , Proteínas de Escherichia coli/imunologia , Modelos Moleculares , Proteínas Periplásmicas de Ligação/imunologia , Ligação Proteica/fisiologia , Conformação ProteicaRESUMO
Trypanosoma cruzi, the etiologic agent of Chagas disease, is covered by a dense glycocalix mainly composed by glycoproteins called mucins which are also the acceptors of sialic acid in a reaction catalyzed by a trans-sialidase (TcTS). Sialylation of trypomastigote mucins protects the parasite from lysis by the anti α-Galp antibodies from serum. The TcTS is essential for the infection process since T. cruzi is unable to biosynthesize sialic acid. The enzyme specifically transfers it from a terminal ß-d-Galp unit in the host glycoconjugate to terminal ß-d-Galp units in the parasite mucins to construct the d-NeuNAc(α2â3)ß-d-Galp motif. On the other hand, although galactose is the most abundant sugar in mucins of both, the infective trypomastigotes and the insect stage epimastigotes, α-d-Galp is only present in the infective stage whereas ß-d-Galf is characteristic of the epimastigote stage of the less virulent strains. Neither α-d-Galp nor d-Galf is acceptor of sialic acid. In the mucins, some of the oligosaccharides are branched with terminal ß-d-Galp units to be able to accept sialic acid in the TcTS reaction. Based on previous reports showing that anti α-Galp antibodies only partially colocalize with sialic acid, we have undertaken the synthesis of the trisaccharide α-d-Galp(1â3)-[ß-d-Galp(1â6)]-d-Galp, the smallest structure containing both, the antigenic d-Galp(α1â3)-d-Galp unit and the sialic acid-acceptor ß-d-Galp unit. The trisaccharide was obtained as the 6-aminohexyl glycoside to facilitate further conjugation for biochemical studies. The synthetic approach involved the α-galactosylation at O-4 of a suitable precursor of the reducing end, followed by ß-galactosylation at O-6 of the same precursor and introduction of the 6-aminohexyl aglycone. The fully deprotected trisaccharide was successfully sialylated by TcTS using either 3'-sialyllactose or fetuin as donors. The product, 6-aminohexyl α-d-NeuNAc(2â3)-ß-d-Galp(1â6)-[α-d-Galp(1â3)]-ß-d-Galp, was purified and characterized.
Assuntos
Anticorpos/química , Glicoproteínas/metabolismo , Neuraminidase/metabolismo , Trissacarídeos/síntese química , Trypanosoma cruzi/metabolismo , Anticorpos/imunologia , Proteínas de Ligação ao Cálcio/imunologia , Sequência de Carboidratos , Técnicas de Química Sintética , Proteínas de Transporte de Monossacarídeos/imunologia , Proteínas Periplásmicas de Ligação/imunologia , Trissacarídeos/metabolismoRESUMO
Moraxella catarrhalis causes otitis media in children and respiratory tract infections in adults with chronic obstructive pulmonary disease (COPD). A vaccine to prevent M. catarrhalis infections would have an enormous impact globally in preventing morbidity caused by M. catarrhalis in these populations. Using a genome mining approach we have identified a sulfate binding protein, CysP, of an ATP binding cassette (ABC) transporter system as a novel candidate vaccine antigen. CysP expresses epitopes on the bacterial surface and is highly conserved among strains. Immunization with CysP induces potentially protective immune responses in a murine pulmonary clearance model. In view of these features that indicate CysP is a promising vaccine antigen, we conducted further studies to elucidate its function. These studies demonstrated that CysP binds sulfate and thiosulfate ions, plays a nutritional role for the organism and functions in intracellular survival of M. catarrhalis in human respiratory epithelial cells. The observations that CysP has features of a vaccine antigen and also plays an important role in growth and survival of the organism indicate that CysP is an excellent candidate vaccine antigen to prevent M. catarrhalis otitis media and infections in adults with COPD.
Assuntos
Vacinas Bacterianas/imunologia , Infecções por Moraxellaceae/prevenção & controle , Proteínas Periplásmicas de Ligação/imunologia , Células A549 , Transportadores de Cassetes de Ligação de ATP/imunologia , Animais , Antígenos de Bactérias/imunologia , Células Epiteliais/microbiologia , Humanos , Camundongos Endogâmicos BALB C , Moraxella catarrhalis , Otite Média/prevenção & controle , Doença Pulmonar Obstrutiva Crônica/prevenção & controle , Proteínas Recombinantes/imunologia , Infecções Respiratórias/microbiologia , Infecções Respiratórias/prevenção & controleRESUMO
In this study, the immunogenicity and protective efficacy of recombinant proteins Omp19 (rO) and P39 (rP) from Brucella abortus were evaluated individually and compared with the cocktail protein (rO+rP) against B. abortus 544 and Brucella melitensis 16M infection in BALB/c mouse model. Intra-peritoneal (I.P.) immunization with rO+rP cocktail developed substantially higher antibody titers predominant with Th1 mediated isotypes (IgG2a/2b). Western blot analysis using anti-rO+rP antibodies showed specific reactivity with native Omp19 (19 kDa) and P39 (39 kDa) among whole cell proteins of B. abortus and B. melitensis. Splenocytes extracted from rO+rP immunized mice induced significantly (P<0.001) higher proliferative responses at 30 µg/ml with considerable expression of pro-inflammatory cytokines (IFN-γ, IL-2 and IL-12) than rO and rP. Macrophage cell (RAW 264.7) monolayer supplemented with anti-rO+rP polysera exhibited enhanced viability against challenge with B. abortus 544 (72.27%) and B. melitensis 16M (68.57%). On the other hand, individual anti-rO and anti-rP polysera resulted in relatively lesser protection against the pathogens (64.79%, 54.45% and 47.13%, 45.11%, respectively). Immunized group of mice when I.P. challenged with 5 × 10(4) CFU of B. abortus 544 and B. melitensis 16M were found significantly (P<0.001) protected in the rO+rP group (log units of protection, spleen: 2.38, 2.12; liver: 1.04, 0.81, respectively) than in rO (spleen: 1.43, 1.21; liver: 0.7, 0.47) and rP (spleen: 1.24, 1.17; liver: 0.65, 0.34). Findings from this study depicted that rO+rP cocktail is highly immunogenic with the Th1 predominant serum antibody titers and T-cell mediated immune protection, would be a valuable intervention in the development of a safer and improved Brucella vaccine.
Assuntos
Antígenos de Bactérias/imunologia , Proteínas da Membrana Bacteriana Externa/imunologia , Vacina contra Brucelose/imunologia , Brucelose/imunologia , Lipoproteínas/imunologia , Proteínas Periplásmicas de Ligação/imunologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Western Blotting , Brucella abortus , Brucella melitensis , Modelos Animais de Doenças , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/farmacologia , Vacinas Sintéticas/imunologiaRESUMO
The membrane proximal region (MPR, residues 649-683) and transmembrane domain (TMD, residues 684-705) of the gp41 subunit of HIV-1's envelope protein are highly conserved and are important in viral mucosal transmission, virus attachment and membrane fusion with target cells. Several structures of the trimeric membrane proximal external region (residues 662-683) of MPR have been reported at the atomic level; however, the atomic structure of the TMD still remains unknown. To elucidate the structure of both MPR and TMD, we expressed the region spanning both domains, MPR-TM (residues 649-705), in Escherichia coli as a fusion protein with maltose binding protein (MBP). MPR-TM was initially fused to the C-terminus of MBP via a 42 aa-long linker containing a TEV protease recognition site (MBP-linker-MPR-TM). Biophysical characterization indicated that the purified MBP-linker-MPR-TM protein was a monodisperse and stable candidate for crystallization. However, crystals of the MBP-linker-MPR-TM protein could not be obtained in extensive crystallization screens. It is possible that the 42 residue-long linker between MBP and MPR-TM was interfering with crystal formation. To test this hypothesis, the 42 residue-long linker was replaced with three alanine residues. The fusion protein, MBP-AAA-MPR-TM, was similarly purified and characterized. Significantly, both the MBP-linker-MPR-TM and MBP-AAA-MPR-TM proteins strongly interacted with broadly neutralizing monoclonal antibodies 2F5 and 4E10. With epitopes accessible to the broadly neutralizing antibodies, these MBP/MPR-TM recombinant proteins may be in immunologically relevant conformations that mimic a pre-hairpin intermediate of gp41.
Assuntos
Vacinas contra a AIDS/química , Proteína gp41 do Envelope de HIV/química , HIV-1/imunologia , Fragmentos de Peptídeos/química , Vacinas contra a AIDS/imunologia , Vacinas contra a AIDS/isolamento & purificação , Dicroísmo Circular , Eletroforese em Gel de Poliacrilamida , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/imunologia , Proteína gp41 do Envelope de HIV/imunologia , Fragmentos de Peptídeos/imunologia , Proteínas Periplásmicas de Ligação/química , Proteínas Periplásmicas de Ligação/imunologia , Ressonância de Plasmônio de Superfície , Proteínas Virais de Fusão/química , Proteínas Virais de Fusão/imunologia , Proteínas Virais de Fusão/isolamento & purificaçãoRESUMO
A label-free immunosensing method based on the conformational change of calcium-binding protein (CBP) depending on analyte concentration was explored for semi-continuous analysis of free Ca(2+). Glucose-galactose-binding protein as a CBP and produced as a recombinant protein by Escherichia coli was used as the immunogen to produce monoclonal antibodies by hybridoma technology. We finally screened the 3-6F cell clone, which produced the desired antibody specific to a particular structural conformation of the protein that occurred only upon CBP-calcium complex formation. To construct an immunosensor, the antibody was immobilized via a secondary antibody on an Octet Red optical fiber-based label-free sensor. Calcium analysis was conducted on the sensor in combination with CBP previously added to the aqueous sample, which distinguished the sensor signal according to the analyte concentration. The immunosensor produced a signal in real time with a response time of approximately 15 min and could be reused for analyses of different samples in a semi-continuous manner. The minimum detection limit of the analyte under optimal conditions was 0.09 mM and the upper limit was about 5 mM (log-logit transformed standard curve linearity: R(2) > 98%). In sample tests with milk, the analytical performance of the sensor was highly correlated (R(2) > 99%) with that of the reference system based on the KMnO4 titration method (ISO 12081). Although the sensor showed cross-reactivity at high concentrations (>1 mM) of cations including zinc, iron, manganese, and copper, these ionic components were not traceable (<0.01 mM) in milk.
Assuntos
Proteínas de Ligação ao Cálcio/metabolismo , Cálcio/análise , Tecnologia de Fibra Óptica/métodos , Imunoensaio/métodos , Leite/química , Proteínas de Transporte de Monossacarídeos/metabolismo , Proteínas Periplásmicas de Ligação/metabolismo , Animais , Anticorpos Imobilizados/imunologia , Cálcio/metabolismo , Proteínas de Ligação ao Cálcio/química , Proteínas de Ligação ao Cálcio/imunologia , Camundongos , Proteínas de Transporte de Monossacarídeos/química , Proteínas de Transporte de Monossacarídeos/imunologia , Fibras Ópticas , Proteínas Periplásmicas de Ligação/química , Proteínas Periplásmicas de Ligação/imunologia , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/metabolismoRESUMO
Riemerella anatipestifer was cultured in both iron restriction media and normal media. Two-dimensional gel electrophoresis identified 23 proteins that significantly increased in the iron restriction media. Of them 12 proteins were analyzed with mass spectrography. Nine of 12 proteins belong to 6 different protein families: fibronectin type iii domain protein, secreted subtilase family protein, phosphoglycerate kinase, translation elongation factor, leucine-rich repeat-containing protein, and Galactose-binding domain-like protein. Other 3 proteins were novel with unknown function. Two novel proteins (Riean_1750 and Riean_1752) were expressed in prokaryotic expression systems. The specificities of these 2 novel proteins to R. anatipestifer were confirmed by western-blotting analysis. The ducks immunized with either protein had low mortality challenged by R. anatipestifer, 33.3% and 16.7%, respectively. The ducks developed 100% immunity when immunized with combined Riean_1750 and Riean_1752 proteins. The data suggested 2 novel proteins play important roles in the bacterial survival in the iron restricted environment. They could be used as subunit vaccines of R. anatipestifer.
Assuntos
Infecções por Flavobacteriaceae/veterinária , Deficiências de Ferro , Doenças das Aves Domésticas/prevenção & controle , Riemerella/imunologia , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/imunologia , Meios de Cultura/química , Patos , Fibronectinas/genética , Fibronectinas/imunologia , Infecções por Flavobacteriaceae/imunologia , Infecções por Flavobacteriaceae/mortalidade , Infecções por Flavobacteriaceae/prevenção & controle , Expressão Gênica , Imunização , Proteínas de Transporte de Monossacarídeos/genética , Proteínas de Transporte de Monossacarídeos/imunologia , Fatores de Alongamento de Peptídeos/genética , Fatores de Alongamento de Peptídeos/imunologia , Proteínas Periplásmicas de Ligação/genética , Proteínas Periplásmicas de Ligação/imunologia , Fosfoglicerato Quinase/genética , Fosfoglicerato Quinase/imunologia , Doenças das Aves Domésticas/imunologia , Doenças das Aves Domésticas/mortalidade , Doenças das Aves Domésticas/virologia , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Riemerella/crescimento & desenvolvimento , Riemerella/metabolismo , Subtilisinas/genética , Subtilisinas/imunologia , Análise de SobrevidaRESUMO
Staphylococcus aureus is a human pathogen causing globally significant morbidity and mortality. The development of antibiotic resistance in S. aureus highlights the need for a preventive vaccine. In the present paper we explore the structure and function of FhuD2 (ferric-hydroxamate uptake D2), a staphylococcal surface lipoprotein mediating iron uptake during invasive infection, recently described as a promising vaccine candidate. Differential scanning fluorimetry and calorimetry studies revealed that FhuD2 is stabilized by hydroxamate siderophores. The FhuD2-ferrichrome interaction was of nanomolar affinity in surface plasmon resonance experiments and fully iron(III)-dependent. We determined the X-ray crystallographic structure of ligand-bound FhuD2 at 1.9 Å (1 Å=0.1 nm) resolution, revealing the bilobate fold of class III SBPs (solute-binding proteins). The ligand, ferrichrome, occupies a cleft between the FhuD2 N- and C-terminal lobes. Many FhuD2-siderophore interactions enable the specific recognition of ferrichrome. Biochemical data suggest that FhuD2 does not undergo significant conformational changes upon siderophore binding, supporting the hypothesis that the ligand-bound complex is essential for receptor engagement and uptake. Finally, immunizations with FhuD2 alone or FhuD2 formulated with hydroxamate siderophores were equally protective in a murine staphylococcal infection model, confirming the suitability and efficacy of apo-FhuD2 as a protective antigen, and suggesting that other class III SBPs might also be exploited as vaccine candidates.
Assuntos
Proteínas de Bactérias/química , Proteínas de Membrana Transportadoras/química , Proteínas Periplásmicas de Ligação/química , Staphylococcus aureus/metabolismo , Fatores de Virulência/química , Animais , Antígenos de Bactérias/química , Antígenos de Bactérias/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Cristalografia por Raios X , Compostos Férricos/metabolismo , Ferricromo/metabolismo , Genes Bacterianos , Humanos , Ácidos Hidroxâmicos/metabolismo , Proteínas de Membrana Transportadoras/genética , Proteínas de Membrana Transportadoras/imunologia , Proteínas de Membrana Transportadoras/metabolismo , Camundongos , Modelos Moleculares , Proteínas Periplásmicas de Ligação/genética , Proteínas Periplásmicas de Ligação/imunologia , Proteínas Periplásmicas de Ligação/metabolismo , Estabilidade Proteica , Sideróforos/metabolismo , Vacinas Antiestafilocócicas/química , Staphylococcus aureus/genética , Staphylococcus aureus/imunologia , Staphylococcus aureus/patogenicidade , Eletricidade Estática , Transferrina/metabolismo , Virulência , Fatores de Virulência/genética , Fatores de Virulência/imunologia , Fatores de Virulência/metabolismoRESUMO
Brucella is gram-negative bacteria responsible for brucellosis in a wide variety of animals and humans. BALB/c mice were immunized with live Escherichia coli expression the p39 gene of Brucella melitensis, a gene coding for the periplasmic binding protein. Mice were injected with either E. coli BL21 (DE3) pEt15b or E. coli BL21 (DE3) pEt15b-p39 alone or adjuvanted with either CpG oligodeoxynucleotides (CpG ODN) or non-CpG ODN. E. coli BL21 (DE3) pEt15b-p39 with CpG ODN or with non-CpG ODN mice groups showed a significant IFN-γ production and T-cell proliferation as a reaction to P39 antigen. In addition, antibody responses (IgG, IgG1 and IgG2a), were only found in these two mice groups. A higher level of protection against B. melitensis 16M were observed in mice immunized with E. coli BL21 (DE3) pEt15b-p39 and CpG ODN comparing with those immunized with E. coli BL21 (DE3) pEt15b-p39 alone or with non-CpG ODN. No protection against B. melitensis 16M was observed in mice immunized with E. coli BL21 (DE3) pEt15b alone or with the adjuvant. Rev.1 protection at 4 and 8 weeks post-challenge was more effective than that observed with E. coli BL21 (DE3) pEt15b-p39 and CpG ODN.
Assuntos
Adjuvantes Imunológicos/administração & dosagem , Vacina contra Brucelose/administração & dosagem , Brucella melitensis/imunologia , Oligodesoxirribonucleotídeos/administração & dosagem , Proteínas Periplásmicas de Ligação/administração & dosagem , Adjuvantes Imunológicos/genética , Animais , Anticorpos Antibacterianos/biossíntese , Vacina contra Brucelose/genética , Vacina contra Brucelose/imunologia , Brucella melitensis/genética , Brucella melitensis/patogenicidade , Brucelose/imunologia , Brucelose/prevenção & controle , Ilhas de CpG/genética , Escherichia coli/genética , Escherichia coli/imunologia , Feminino , Imunidade Celular , Camundongos , Camundongos Endogâmicos BALB C , Oligodesoxirribonucleotídeos/imunologia , Proteínas Periplásmicas de Ligação/genética , Proteínas Periplásmicas de Ligação/imunologia , Proteínas Recombinantes/administração & dosagem , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Fatores de TempoRESUMO
The 'art' genes encode specific arginine uptake proteins, and are repressed by the repressible promoters of ArgR, affecting transcription of artJ. Cpb0502, the arginine-binding periplasmic protein 2 precursor from Chlamydophila pneumoniae TW-183 strains, is responsible for arginine transport. As C. pneumoniae is difficult to isolate and culture, there have been many studies of better ways to detect it. A microimmunofluorescence assay (MIF) is still considered to be the 'gold standard' for detecting C. pneumoniae. Although MIF has its own limitations, a number of immunogenic antigens have been shown to be C. pneumoniae specific by this test. Here, we report Cpb0502 as a specific immunogenic antigen against C. pneumoniae as it was detected only in human infection sera of C. pneumoniae but not in Legionella pneumophila and Mycoplasma pneumoniae infection sera, showing high specificity and sensitivity by MIF, western blot and ELISA analysis. And also the crystal structure of Cpb0502 was determined to be a dimer at 2.07Å, revealing a similar backbone structure to a histidine kinase receptor, HK29S. Therefore we may suggest that Cpb0502 is a candidate immunogenic antigen for better diagnosis of C. pneumoniae.
Assuntos
Antígenos de Bactérias/análise , Proteínas de Bactérias/análise , Infecções por Chlamydophila/diagnóstico , Chlamydophila pneumoniae/isolamento & purificação , Proteínas Periplásmicas de Ligação/análise , Sequência de Aminoácidos , Antígenos de Bactérias/química , Antígenos de Bactérias/imunologia , Arginina/metabolismo , Proteínas de Bactérias/química , Proteínas de Bactérias/imunologia , Linhagem Celular , Chlamydophila pneumoniae/imunologia , Chlamydophila pneumoniae/metabolismo , Cristalografia por Raios X , Técnica Direta de Fluorescência para Anticorpo , Genes Reguladores , Humanos , Dados de Sequência Molecular , Proteínas Periplásmicas de Ligação/química , Proteínas Periplásmicas de Ligação/imunologia , Estrutura Secundária de Proteína , Estrutura Terciária de ProteínaRESUMO
The merozoite surface protein-1 (MSP-1) from Plasmodium vivax was evaluated as an oral vaccine candidate by cloning and expressing the interspecies conserved block 10 (ICB10) of the MSP-1 from a Korean isolate in Escherichia coli. The expressed fusion protein contained ICB10 and a maltose-binding protein (MBP), rPv54, has a molecular weight of approximately 54 kDa as determined by SDS-PAGE analysis. IgG against rPv54 was successfully produced in BALB/c mice by oral immunization and sustained for more than 4 months. IgG2b was dominantly produced in both oral and parenteral immunizations. The rPv54 increased the frequency of NK, NKT, CD4+ T, CD8+ T, and B cells in both immunizations. IL-5 and TNF-alpha were increased in both significantly. In conclusion, rPv54 might be a valuable potential vaccine candidate for the oral and parenteral immunization against vivax malaria.
Assuntos
Proteína 1 de Superfície de Merozoito/imunologia , Proteínas Periplásmicas de Ligação/imunologia , Plasmodium vivax/imunologia , Vacinas Protozoárias/administração & dosagem , Proteínas Recombinantes de Fusão/imunologia , Administração Oral , Animais , Anticorpos Antiprotozoários/biossíntese , Feminino , Humanos , Imunoglobulina G/biossíntese , Infusões Parenterais , Interleucina-5/metabolismo , Malária Vivax/prevenção & controle , Proteínas Ligantes de Maltose , Proteína 1 de Superfície de Merozoito/química , Proteína 1 de Superfície de Merozoito/genética , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Periplásmicas de Ligação/química , Proteínas Periplásmicas de Ligação/genética , Vacinas Protozoárias/imunologia , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Baço/citologia , Baço/imunologia , Fator de Necrose Tumoral alfa/metabolismo , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologiaRESUMO
Immunization using recombinant maltose binding protein-gonadotropin releasing hormone (MBP-GnRH6) altered both testicular development and transcription of the pituitary GnRH receptor (GnRHR) gene in boars. Scrotal measurement and blood samples were taken at 4-week interval after immunization at 9 weeks of age. The concentrations of testosterone and anti-GnRH antibodies in serum were determined by radioimmunoassay and enzyme-linked immunosorbent assay, respectively. The results showed that active immunization with MBP-GnRH6 increased the serum concentration of anti-GnRH antibodies (P<0.05) and reduced the serum concentration of testosterone (P<0.05) as compared with MBP controls. At 25 weeks of age, boars were sacrificed and testes were evaluated histologically. Testicular development was suppressed in the MBP-GnRH6 immunized animals as compared with MBP immunized boars. MBP-GnRH6 immunized pigs exhibited mounting behavior 4 weeks later than MBP immunized boars. No mature spermatozoa were observed from MBP-GnRH6 immunized animals. By real-time quantitative PCR analysis, the amount of GnRHR mRNA in the pituitary tissue was found to be significantly lower in MBP-GnRH6 immunized animals than in controls (P<0.05). These data demonstrate that recombinant MBP-GnRH6 was effective in immunological castration in boars.
Assuntos
Hormônio Liberador de Gonadotropina/imunologia , Hipófise/química , Receptores LHRH/genética , Esterilização Reprodutiva/veterinária , Suínos/crescimento & desenvolvimento , Testículo/crescimento & desenvolvimento , Animais , Anticorpos/sangue , Hormônio Liberador de Gonadotropina/genética , Hormônio Liberador de Gonadotropina/fisiologia , Masculino , Proteínas Ligantes de Maltose , Proteínas Periplásmicas de Ligação/genética , Proteínas Periplásmicas de Ligação/imunologia , Reação em Cadeia da Polimerase , RNA Mensageiro/análise , Proteínas Recombinantes de Fusão/imunologia , Comportamento Sexual Animal , Espermatozoides/fisiologia , Esterilização Reprodutiva/métodos , Suínos/metabolismo , Testículo/anatomia & histologia , Testosterona/sangue , Vacinação/veterináriaRESUMO
The present study was conducted to investigate the role of iron-regulated outer membrane proteins (IROMP) of Pasteurella multocida B:2 in mice as potential immunogens. Outer membrane proteins extracted from P. multocida B:2 grown under normal (OMP) and iron-deficient (IROMP) conditions were subjected to discontinuous SDS-PAGE. Nine polypeptides of MW ranging from 85.1 to 16.7 kDa from OMP preparations and two additional polypeptides of MW 95.4 and 89.1 kDa from IROMP preparations were observed with bands of MW 37.2 and 34.7 kDa as major proteins. Mice were immunized twice with OMP, IROMP-enriched fractions and whole cell lysate (WCL) via subcutaneous route at day 0 and 21. Antibody titers were determined from sera collected at weekly interval and protection was studied against challenge using 10(2) cfu of P. multocida two weeks after secondary immunization via intranasal and subcutaneous routes. IROMP and OMP immunized mice provoked significant antibody responses and IROMP induced higher antibody responses. IROMP and OMP immunized mice showed protection (100%) upon intranasal challenge and a protection (84%) following subcutaneous challenge as compared to high mortality (84%) in control mice. These results indicate that OMP enriched with IROMP fractions can be superior means of immunization.
Assuntos
Proteínas da Membrana Bacteriana Externa/imunologia , Proteínas de Bactérias/imunologia , Modelos Animais de Doenças , Proteínas de Ligação ao Ferro/imunologia , Ferro/farmacologia , Infecções por Pasteurella/imunologia , Pasteurella multocida/imunologia , Proteínas Periplásmicas de Ligação/imunologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Ensaio de Imunoadsorção Enzimática , Feminino , Imunização , Camundongos , Infecções por Pasteurella/metabolismo , Pasteurella multocida/patogenicidadeRESUMO
The use of Lactococcus lactis to deliver a chosen antigen to the mucosal surface has been shown to elicit an immune response in mice and is a possible method of vaccination in humans. The recent discovery on Gram-positive bacteria of pili that are covalently attached to the bacterial surface and the elucidation of the residues linking the major and minor subunits of such pili suggests that the presentation of an antigen on the tip of pili external to the surface of L. lactis might constitute a successful vaccine strategy. As a proof of principle, we have fused a foreign protein (the Escherichia coli maltose-binding protein) to the C-terminal region of the native tip protein (Cpa) of the T3 pilus derived from Streptococcus pyogenes and expressed this fusion protein (MBP*) in L. lactis. We find that MBP* is incorporated into pili in this foreign host, as shown by Western blot analyses of cell wall proteins and by immunogold electron microscopy. Furthermore, since the MBP* on these pili retains its native biological activity, it appears to retain its native structure. Mucosal immunization of mice with this L. lactis strain expressing pilus-linked MBP* results in production of both a systemic and a mucosal response (IgG and IgA antibodies) against the MBP antigen. We suggest that this type of mucosal vaccine delivery system, which we term UPTOP (for unhindered presentation on tips of pili), may provide an inexpensive and stable alternative to current mechanisms of immunization for many serious human pathogens.
Assuntos
Vacinas Bacterianas/imunologia , Proteínas de Escherichia coli/imunologia , Fímbrias Bacterianas/genética , Vetores Genéticos , Imunidade Humoral , Imunidade nas Mucosas , Lactococcus lactis/genética , Proteínas Periplásmicas de Ligação/imunologia , Animais , Anticorpos Antibacterianos/análise , Anticorpos Antibacterianos/sangue , Vacinas Bacterianas/genética , Western Blotting , Proteínas de Escherichia coli/biossíntese , Proteínas de Escherichia coli/genética , Feminino , Humanos , Imunoglobulina A/análise , Imunoglobulina G/sangue , Lactococcus lactis/química , Camundongos , Microscopia Imunoeletrônica , Proteínas Periplásmicas de Ligação/biossíntese , Proteínas Periplásmicas de Ligação/genética , Proteínas Recombinantes de Fusão/biossíntese , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/imunologia , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologiaRESUMO
The periplasmic binding protein (P39) antigen of Brucella melitensis 16 M was previously identified as Th1 dominant antigens. In this study, the potential for this antigen to function as vaccine against B. melitensis 16 M infection in BALB/c mice has been analyzed, and the humoral and cellular immune responses induced have been also characterized. Mice were injected intraperitoneally with live Escherichia coli alone or with that which express Brucella P39, two times at 4 weeks intervals. The live E. coli BL21 (DE3) pEt15b-p39 vaccine elicited a T-cell-proliferative response and also induced a gamma interferon production upon re-stimulation with either the bacterial extract or P39 as a specific antigen. Also the live E. coli BL21 (DE3) pEt15b-p39 vaccine has been found to induce a strong humoral response (IgG1 and IgG2a). Compared to the saline-inoculated control, vaccination of mice with E. coli BL21pEt15b-p39 at 3 weeks prior to the challenge infection, significantly reduced the number of strain 16 M bacteria in spleens at 4 and 8 weeks post-challenge infection in all vaccinated mice (p<0.001).
Assuntos
Vacina contra Brucelose/imunologia , Brucelose/prevenção & controle , Proteínas Periplásmicas de Ligação/imunologia , Células Th1/imunologia , Animais , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/imunologia , Antígenos de Bactérias/imunologia , Brucella melitensis/imunologia , Brucelose/imunologia , Proliferação de Células , Escherichia coli/genética , Escherichia coli/imunologia , Feminino , Imunidade Celular , Imunidade Humoral , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Interferon gama/imunologia , Interleucina-5/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Proteínas Periplásmicas de Ligação/genética , Baço/citologia , Baço/imunologiaRESUMO
BACKGROUND: The application of high throughput molecular techniques such as SEREX are resulting in the identification of a multitude of tumor associated antigens. As newly identified antigens are incorporated into a variety of clinical trials, standardization of immunologic monitoring methods becomes increasingly important. We questioned whether mammalian cell expression of a histadine-linked human protein could be used to produce antigen suitable for detecting tumor-specific humoral immunity and whether such an assay could be amenable to standardization for clinical use. METHODS: We designed a his-tagged capture ELISA based on lysate from genetically engineered CHO cells for detection of antibodies to insulin-like growth factor binding protein 2, a novel tumor antigen. We performed technical and preliminary clinical validation studies, including comparison to a standard indirect ELISA based on commercially prepared recombinant antigen. RESULTS: The his-tagged capture ELISA could be standardized. Precision experiments resulted in CVs < 15%. Linearity and calibration experiments demonstrated r2 values of 0.99. In comparison to Western blot analysis, his-tag and indirect ELISA accurately identified 88% and 93% of samples, respectively. Sample concordance between capture and indirect assays was highly significant (p = 0.003). Furthermore, significantly greater levels of IGFBP-2 antibody immunity were found in cancer patients compared to normal controls (p = 0.008). CONCLUSION: A genetically engineered cell lysate based ELISA can be amenable to standardization and can detect increased levels of antibody immunity to tumor-associated antigen in cancer patients compared to non tumor-bearing healthy controls.
Assuntos
Anticorpos Antineoplásicos/análise , Neoplasias da Mama/diagnóstico , Neoplasias Colorretais/diagnóstico , Ensaio de Imunoadsorção Enzimática/métodos , Proteína 2 de Ligação a Fator de Crescimento Semelhante à Insulina/imunologia , Adolescente , Adulto , Idoso , Animais , Formação de Anticorpos , Neoplasias da Mama/imunologia , Neoplasias da Mama/patologia , Células CHO , Linhagem Celular Tumoral , Neoplasias Colorretais/imunologia , Neoplasias Colorretais/patologia , Cricetinae , Cricetulus , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/imunologia , Proteínas de Escherichia coli/metabolismo , Feminino , Humanos , Proteína 2 de Ligação a Fator de Crescimento Semelhante à Insulina/genética , Proteína 2 de Ligação a Fator de Crescimento Semelhante à Insulina/metabolismo , Masculino , Pessoa de Meia-Idade , Proteínas Periplásmicas de Ligação/genética , Proteínas Periplásmicas de Ligação/imunologia , Proteínas Periplásmicas de Ligação/metabolismo , Valor Preditivo dos Testes , Sensibilidade e EspecificidadeRESUMO
Lysozymes are ancient and important components of the innate immune system of animals that hydrolyze peptidoglycan, the major bacterial cell wall polymer. Bacteria engaging in commensal or pathogenic interactions with an animal host have evolved various strategies to evade this bactericidal enzyme, one recently proposed strategy being the production of lysozyme inhibitors. We here report the discovery of a novel family of bacterial lysozyme inhibitors with widespread homologs in gram-negative bacteria. First, a lysozyme inhibitor was isolated by affinity chromatography from a periplasmic extract of Salmonella Enteritidis, identified by mass spectrometry and correspondingly designated as PliC (periplasmic lysozyme inhibitor of c-type lysozyme). A pliC knock-out mutant no longer produced lysozyme inhibitory activity and showed increased lysozyme sensitivity in the presence of the outer membrane permeabilizing protein lactoferrin. PliC lacks similarity with the previously described Escherichia coli lysozyme inhibitor Ivy, but is related to a group of proteins with a common conserved COG3895 domain, some of them predicted to be lipoproteins. No function has yet been assigned to these proteins, although they are widely spread among the Proteobacteria. We demonstrate that at least two representatives of this group, MliC (membrane bound lysozyme inhibitor of c-type lysozyme) of E. coli and Pseudomonas aeruginosa, also possess lysozyme inhibitory activity and confer increased lysozyme tolerance upon expression in E. coli. Interestingly, mliC of Salmonella Typhi was picked up earlier in a screen for genes induced during residence in macrophages, and knockout of mliC was shown to reduce macrophage survival of S. Typhi. Based on these observations, we suggest that the COG3895 domain is a common feature of a novel and widespread family of bacterial lysozyme inhibitors in gram-negative bacteria that may function as colonization or virulence factors in bacteria interacting with an animal host.
Assuntos
Anti-Infecciosos/imunologia , Inibidores Enzimáticos/imunologia , Bactérias Gram-Negativas/imunologia , Tolerância Imunológica , Muramidase/imunologia , Animais , Anti-Infecciosos/antagonistas & inibidores , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/imunologia , Proteínas de Transporte/metabolismo , Galinhas , Inibidores Enzimáticos/química , Escherichia coli/enzimologia , Escherichia coli/genética , Escherichia coli/imunologia , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/imunologia , Proteínas de Escherichia coli/metabolismo , Inativação Gênica , Bactérias Gram-Negativas/enzimologia , Bactérias Gram-Negativas/genética , Humanos , Muramidase/antagonistas & inibidores , Proteínas Periplásmicas de Ligação/química , Proteínas Periplásmicas de Ligação/genética , Proteínas Periplásmicas de Ligação/imunologia , Pseudomonas aeruginosa/enzimologia , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/imunologia , Salmonella enteritidis/enzimologia , Salmonella enteritidis/genética , Salmonella enteritidis/imunologia , Espectrometria de Massas por Ionização por Electrospray , Espectrometria de Massas em Tandem , Fatores de VirulênciaRESUMO
The increasing prevalence of multi-drug-resistant (MDR) strains of Pseudomonas aeruginosa among critically ill humans is of significant concern. In the current study, we show that MDR clinical isolates of P. aeruginosa representing three distinct genotypes that display high virulence against intestinal epithelial cells, form novel appendage-like structures on their cell surfaces. These appendages contain PstS, an extracellular phosphate binding protein. Using anti-PstS antibodies, we determined that the PstS-rich appendages in MDR strains are involved in adherence to and disruption of the integrity of cultured intestinal epithelial cell monolayers. The outer surface-expressed PstS protein was also identified to be present in P. aeruginosa MPAO1, although to a lesser degree, and its role in conferring an adhesive and barrier disruptive phenotype against intestinal epithelial cells was confirmed using an isogenic DeltaPstS mutant. Formation of the PstS rich appendages was induced during phosphate limitation and completely suppressed in phosphate-rich media. Injection of MDR strains directly into the intestinal tract of surgically injured mice, a known model of phosphate limitation, caused high mortality rates (60%-100%). Repletion of intestinal phosphate in this model completely prevented mortality. Finally, significantly less outer surface PstS was observed in the MPAO1 mutant DeltaHxcR thus establishing a role for the alternative type II secretion system Hxc in outer surface PstS expression. Gene expression analysis performed by RT-PCR confirmed this finding and further demonstrated abundant expression of pstS analogous to pa5369, pstS analogous to pa0688/pa14-55410, and hxcX in MDR strains. Taken together, these studies provide evidence that outer surface PstS expression confers a highly virulent phenotype of MDR isolates against the intestinal epithelium that alters their adhesive and barrier disrupting properties against the intestinal epithelium.
Assuntos
Farmacorresistência Bacteriana Múltipla , Regulação Bacteriana da Expressão Gênica , Proteínas Periplásmicas de Ligação/metabolismo , Pseudomonas aeruginosa/genética , Pseudomonas aeruginosa/patogenicidade , Animais , Aderência Bacteriana/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/imunologia , Proteínas de Bactérias/metabolismo , Biofilmes , Células CACO-2 , DNA Bacteriano/genética , Modelos Animais de Doenças , Humanos , Mucosa Intestinal/microbiologia , Mucosa Intestinal/fisiopatologia , Longevidade , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Proteínas Periplásmicas de Ligação/química , Proteínas Periplásmicas de Ligação/imunologia , Infecções por Pseudomonas/imunologia , Infecções por Pseudomonas/metabolismo , Infecções por Pseudomonas/fisiopatologia , Pseudomonas aeruginosa/ultraestruturaRESUMO
The MHC-encoded cofactor DM catalyzes endosomal loading of peptides onto MHC class II molecules. Despite evidence from in vitro experiments that DM acts to selectively edit the repertoire of class II:peptide complexes, the consequence of DM expression in vivo, or a predictive pattern of DM activity in the specificity of CD4 T cell responses has remained unresolved. Therefore, to characterize DM function in vivo we used wild-type (WT) or DM-deficient (DM(-/-)) mice of the H-2(d) MHC haplotype and tested the hypothesis that DM promotes narrowing of the repertoire of class II:peptide complexes displayed by APC, leading to a correspondingly selective CD4 T cell response. Surprisingly, our results indicated that DM(-/-) mice do not exhibit a broadened CD4 T cell response relative to WT mice, but rather shift their immunodominance pattern to new peptides, a pattern associated with a change in class II isotype-restriction. Specifically, we found that CD4 T cell responses in WT mice were primarily restricted to the I-A class II molecule, whereas DM(-/-) mice recognize peptides in the context of I-E. The observed shift in isotype-restriction appeared to be due in part to a modification in the peripheral CD4 T cell repertoire available for peptide recognition.