RESUMO
Virus-like particles (VLPs) based on the small envelope protein of hepatitis B virus (HBsAg-S) are immunogenic at the B- and T-cell level. In this study, we inserted overlapping sequences encoding the carboxy terminus of the Helicobacter pylori katA gene product into HBsAg-S. The HBsAg-S-KatA fusion proteins were able to assemble into secretion-competent VLPs (VLP-KatA). The VLP-KatA proteins were able to induce KatA-specific antibodies in immunized mice. The mean total IgG antibody titers 41 days post-primary immunization with VLP-KatA (2.3 × 10(3)) were significantly greater (P < 0.05) than those observed for vaccination with VLP alone (5.2 × 10(2)). Measurement of IgG isotypes revealed responses to both IgG1 and IgG2a (mean titers, 9.0 × 10(4) and 2.6 × 10(4), respectively), with the IgG2a response to vaccination with VLP-KatA being significantly higher than that for mice immunized with KatA alone (P < 0.05). Following challenge of mice with H. pylori, a significantly reduced bacterial load in the gastric mucosa was observed (P < 0.05). This is the first report describing the use of VLPs as a delivery vehicle for H. pylori antigens.
Assuntos
Proteínas de Bactérias/imunologia , Vacinas Bacterianas/imunologia , Catalase/imunologia , Infecções por Helicobacter/prevenção & controle , Antígenos de Superfície da Hepatite B/imunologia , Animais , Anticorpos Antibacterianos/sangue , Carga Bacteriana , Proteínas de Bactérias/genética , Vacinas Bacterianas/administração & dosagem , Catalase/genética , Epitopos/imunologia , Feminino , Infecções por Helicobacter/imunologia , Helicobacter pylori/genética , Helicobacter pylori/imunologia , Antígenos de Superfície da Hepatite B/genética , Vírus da Hepatite B/genética , Vírus da Hepatite B/imunologia , Imunoglobulina G/sangue , Camundongos , Camundongos Endogâmicos C57BL , Vacinação , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/imunologia , Vacinas de Partículas Semelhantes a Vírus/administração & dosagem , Vacinas de Partículas Semelhantes a Vírus/imunologia , Proteínas Virais de Fusão/imunologiaRESUMO
Enzyme immunoassays (EIAs) are widely used in the clinical laboratory and research institutes for the detection of biologically relevant analytes. Almost all EIAs are heterogeneous in nature and require multiple steps of process. In contrast, homogeneous immunoassays (HA) offer a simplified one-step approach with a number of potential advantages over contemporary heterogeneous EIAs such as higher throughput and greater clinical utility. Utilizing TEM-1 beta-lactamase as a reporter enzyme, we have developed HAs based on in vitro protein fragment complementation (PCA) for the detection of antibodies and potentially be used for antigens or other biomarkers. In this proof-of-principle study we demonstrate the successful in vitro differentiation of anti-herpes simplex virus (HSV) type-1 and type-2 Immunoglobulin G (IgG) in human serum with high sensitivity and specificity.