Th2-biased immune response and agglutinating antibodies generation by a chimeric protein comprising OmpC epitope (323 –336) of Aeromonas hydrophila and LTB

AbstractAeromonas hydrophila is responsible for causing fatal infections in freshwater fishes. Besides chemical/antibiotic treatment and whole-cell vaccine, no subunit vaccine is currently available forA. hydrophila. Outer membrane proteins of gram-negative bacteria have been reported as effective vaccine candidates. Peptide antigens elicit focused immune responses against immunodominant stretches of the antigen. We have attempted to characterize the immunogenicity of linear B-cell epitopes of outer membrane protein (OmpC) ofA. hydrophila identified using in silico tools, in conjugation with heat-labile enterotoxin B (LTB) subunit ofEscherichia coli as a carrier protein. Antisera against the fusion protein harboring 323 –336 residues of theAhOmpC (raised in mice) showed maximum cross-reactivity with the parent protein OmpC and LTB. The fusion protein displayed efficient GM1 ganglioside receptor binding, retaining the adjuvanicity of LTB. Antibody isotype profile and in vitro T-cell response analysis, cytokine ELISA, and array analysis collectively revealed a Th2-biased mixed T-helper cell response. Agglutination assay and flow cytometry analysis validated the ability of anti-fusion protein antisera to recognize the surface exposed epitopes onAeromonas cells, demonstrating its neutralization potential. Oral immunization studies inLabeo rohita resulted in the generation of long-lasting humoral immune response, and the antisera could cross-react with the fusion protein as well...
Source: Immunologic Research - Category: Allergy & Immunology Source Type: research