RESUMEN
Protective properties of immunoglobulin A (IgA) monoclonal antibodies (MAbs) directed against O and H antigens of Salmonella enterica serotype Enteritidis (S. enteritidis) were evaluated in a model of generalized infection after intranasal (i.n.) inoculation of BALB/c mice. Passive i.n. instillation of antibodies 1 h before i.n. challenge did not prevent infection, and mice developed rapid inflammatory response in the lower respiratory tract. The passive systemic immunization was partially protective and a single intravenous (i.v.) injection of both O and H antigen specific IgA antibodies prolonged survival period of the infected animals. Permanent secretion of O:9 specific IgA MAb 177E6 into the respiratory tract in a "backpack" tumor model protected 50% of animals infected i.n. with a high dose of virulent S. enteritidis strain. Thus, secretory IgA (S-IgA) directed against O:9 antigen alone can prevent bacterial invasion in the respiratory epithelium.
Asunto(s)
Anticuerpos Monoclonales/farmacología , Antígenos Bacterianos/inmunología , Inmunoglobulina A/inmunología , Enfermedades Pulmonares/microbiología , Antígenos O/inmunología , Salmonelosis Animal/inmunología , Salmonella enteritidis/inmunología , Animales , Anticuerpos Antibacterianos/inmunología , Anticuerpos Antibacterianos/farmacología , Anticuerpos Monoclonales/inmunología , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Inmunización Pasiva/métodos , Inmunoglobulina A/farmacología , Cinética , Enfermedades Pulmonares/inmunología , Enfermedades Pulmonares/prevención & control , Ratones , Ratones Endogámicos BALB C , Salmonelosis Animal/microbiología , Salmonelosis Animal/prevención & controlRESUMEN
A novel lectin from the root of Arum maculatum was isolated by saline extraction and purified by cold ethanol precipitation and subsequent fractionation on Superose 6 column. The lectin named A. maculatum agglutinin is a non-glycosylated protein with 20-kDa molecular mass agglutinating human ejaculated spermatozoa, but not human erythrocytes. The agglutination was blocked in the presence of N-acetylneuraminic acid indicating that the lectin is sialoglycoprotein specific. Chlamydia pneumoniae strain AR-39 showed considerable potential to grow in murine L-929 fibroblast cells. Pretreatment of the cell monolayers with purified lectin reduced the entry and intracellular replication of C. pneumoniae. These results suggest that the isolated lectin prevents attachment by binding to a C. pneumoniae specific sialoglycoprotein receptor expressed on the surface of L-929 fibroblast cells.
Asunto(s)
Aglutininas/farmacología , Araceae , Chlamydophila pneumoniae/efectos de los fármacos , Lectinas/farmacología , Proteínas de Plantas/farmacología , Espermatozoides/efectos de los fármacos , Pruebas de Aglutinación , Aglutininas/aislamiento & purificación , Animales , Línea Celular , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fibroblastos/microbiología , Humanos , Lectinas/aislamiento & purificación , Masculino , Lectinas de Plantas , Proteínas de Plantas/aislamiento & purificación , Espermatozoides/fisiologíaRESUMEN
A murine monoclonal antibody (MAb) 202D7 of IgG3 isotype recognizes a lipopolysaccharide (LPS) epitope of Chlamydia spp. and cross-reacts with the Re chemotype LPS of Salmonella and Escherichia coli. The antibody exhibits strong complement activating properties and stimulates phagocytosis of Salmonella enterica serovar Minnesota Re mutant by murine macrophages. Salmonella Re mutants are non-invasive for cell monolayers but still can enter and replicate in L-929 murine fibroblast cells. The entry of bacteria within the cells increases five-fold in the presence of MAb 202D7. The antibody mediates attachment and enhances five-fold the infectivity of Chlamydia pneumoniae into L-929 cells, which suggests a possible IgG-mediated mechanism of entry and survival of the pathogen in fibroblast cells.
Asunto(s)
Anticuerpos Monoclonales/inmunología , Chlamydophila pneumoniae/patogenicidad , Inmunoglobulina G/inmunología , Lipopolisacáridos/inmunología , Salmonella enterica/patogenicidad , Animales , Acrecentamiento Dependiente de Anticuerpo , Línea Celular , Chlamydophila pneumoniae/inmunología , Reacciones Cruzadas , Epítopos/inmunología , Fibroblastos/microbiología , Humanos , Macrófagos Peritoneales/microbiología , Ratones , Ratones Endogámicos BALB C , Fagocitosis , Salmonella enterica/genética , Salmonella enterica/inmunologíaRESUMEN
Hybridomas were generated after intragastral immunization of BALB/c mice with live Salmonella suberu and subsequent fusion between isolated spleen lymphoblasts and myeloma cells. Three monoclonal antibodies (MAbs) of immunoglobulin A (IgA) isotype were selected and characterized. All of them were found to recognize the H:g epitope in enzyme-linked immunosorbent assay and immunoblotting but did not react with all H:g-expressing strains in slide agglutination test. All MAbs strongly agglutinated Salmonella enteritidis type strain and a large number of S. enteritidis clinical isolates. They were not bactericidal in the presence of complement. All hybridoma clones produced secretory IgA forms, which were found in the gastrointestinal tract of mice bearing hybridoma as a subcutaneous 'backpack' tumor or after intravenous application of purified MAbs. The IgA MAbs stability demonstrated in different tests together with their antigen specificity and strong agglutination ability make them a useful diagnostic tool for serotyping of Salmonella strains.
Asunto(s)
Anticuerpos Monoclonales/biosíntesis , Antígenos Bacterianos/inmunología , Flagelina/inmunología , Inmunoglobulina A Secretora/biosíntesis , Salmonella enteritidis/inmunología , Animales , Anticuerpos Antibacterianos/biosíntesis , Anticuerpos Antibacterianos/inmunología , Anticuerpos Monoclonales/inmunología , Especificidad de Anticuerpos , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Hibridomas , Immunoblotting , Inmunoglobulina A Secretora/inmunología , Ratones , Ratones Endogámicos BALB CRESUMEN
The protective potential of immunoglobulin A (IgA) monoclonal antibodies (MAbs) directed against O and H antigens of Salmonella enterica serotype Enteritidis to prevent bacterial adhesion to and invasion of HEp-2 cells was evaluated. Although anti-flagellar IgA MAbs showed strong agglutinating capacities, they did not protect cell monolayers. In contrast, IgA MAbs specific for the O:9 epitope of Salmonella lipopolysaccharide antigen alone prevented S. enterica serotype Enteritidis entry and replication within HEp-2 cells, and the protection was not mediated by direct binding of antibodies to bacterial adhesins or by agglutination of microorganisms.