This study aimed to investigate the antibody responses in mice immunized with Gnathostoma spinigerum crude antigen (GsAg) incorporated with the combined adjuvant, a synthetic oligonucleotide containing unmethylated CpG motif (CpG ODN 1826) and a stable water in oil emulsion (Montanide ISA720). Mice immunized with GsAg and combined adjuvant produced all antibody classes and subclasses to GsAg except IgA. IgG2a/2b/3 but not IgG1 subclasses were enhanced by immunization with CpG ODN 1826 when compared with the control groups immunized with non-CpG ODN and Montanide ISA or only with Montanide ISA, suggesting a biased induction of a Th1-type response by CpG ODN. After challenge infection with live G. spinigerum larvae, the levels of IgG2a/2b/3 antibody subclasses decreased immediately and continuously, while the IgG1 subclass remained at high levels. This also corresponded to a continuous decrease of the IgG2a/IgG1 ratio after infection. Only IgM and IgG1 antibodies, but not IgG2a/2b/3, were significantly produced in adjuvant control groups after infection. These findings suggest that G. spinigerum infection potently induces a Th2-type biased response.
Adjuvants, Immunologic/*administration & dosage ; Animals ; Antibodies, Helminth/*blood ; Antigens, Helminth/*administration & dosage/*immunology ; Gnathostoma/*immunology ; Immunoglobulin G/blood ; Immunoglobulin M/blood ; Male ; Mannitol/administration & dosage/*analogs & derivatives ; Mice ; Oleic Acids/*administration & dosage ; Oligodeoxyribonucleotides/*administration & dosage ; Th1 Cells/immunology ; Th2 Cells/immunology

Objective: To identify the monoclonal antibody specific to Aeromonas spp., a Gram negative bacteria causing gastroenteritis and wound infection. Methods: The monoclone, namely 88F2-3F4, was produced from hybridoma technology. The specificity of antibody secreted from 88F2-3F4 was tested against other Gram negative bacteria frequently found in gastrointestinal tract. Then the antibody was used for searching Aeromonas antigens in artificial seeded rectal swab cultures by dot-blot enzyme linked immunosorbent assay. Results: 88F2-3F4 produced an antibody that recognized an antigen with a molecular mass of 8.5 kDa in all 123 isolates of the seven Aeromonas species tested, but recognized no epitope of any other Gram-negative bacterium typically found in the gastrointestinal tract. A dot-blot enzyme linked immunosorbent assay based on this antibody showed 86.49% sensitivity and 92.13% specificity. Conclusions: 88F2-3F4 monoclonal antibody could react with all Aeromonas isolates, but not other Gram negative bacteria, therefore it should be a useful tool for the detection of Aeromonas antigen in clinical and environmental samples.