Immunogenicity and protective role of an IgA reactive 31-kDa antigen of Vibrio cholerae O139

Abstract

Immunoglobulin A (IgA) is important in protective immunity against infection by Vibrio cholerae. In this study, the immune response to and protective role of a 31-kDa antigen of V. cholerae O139, reacting with IgA antibodies present in the sera of cholera patients and common to V. cholerae strains O139 and O1 was evaluated in BALB/c mice. From the various antigens of V. cholerae O139 and V. cholerae O1 which reacted with IgA antibodies in sera of a cholera patient, a 31-kDa common antigen was selected and puri®ed by DEAE-Sepharose CL 6B column chromatography. Oral administration of live V. cholerae O139 in BALB/c mice elicited an IgA response to the 31-kDa antigen in serum and intestinal¯uid, and a proliferation of the splenic lymphocytes on stimulation with the same antigen. The cytokine pro®le of these splenic lymphocytes revealed a shift from a mixed Th1 and Th2 response ± interleukin-10 (IL-10) and interferon-ã ± in the ®rst week after infection to a Th2 type of response ± IL-10 ± in the third week. In passive protection studies, hyperimmune serum to the 31-kDa antigen was able to protect infant mice against challenge with O139 and O1 strains. These results demonstrate the ability of the 31-kDa antigen of V. cholerae O139 to induce humoral and cellular immune responses in mice, and its immunoprotective nature.

Overexpression, Purification, and Immunogenicity of Recombinant Porin Proteins of Salmonella enterica Serovar Typhi (S. Typhi)

“…Sera were collected prior to first dose and 7 days after the last dose. Quantitation of antibodies to the recombinant OmpF or OmpC was performed using ELISA by a previously described method [12].…”

Th1-type immune response to infection by pYV-cured phoP-phoQ null mutant of Yersinia pseudotuberculosis is defective in mouse model

“…For cell proliferation and cytokine assays, spleen cells (lymphocytes) were prepared by lysing erythrocytes with ammonium chloride solution (Kumar et al 2001). The cell proliferation was carried out using alamar blue dye (Biosource, USA) by the method of Zhi-Jun et al (1997).…”

“…Preparation of whole cell sonicated (WCS) antigens WCS antigens of strains 1A and DPQ1A were prepared by earlier described method with slight modifications (Kumar et al 2001). Briefly, bacteria were grown overnight in 20 ml BHI broth at 28°C under shaking conditions (200 rpm).…”

“…Sera were collected for 4 weeks at weekly intervals to quantify IgG antibody response. WCS antigen of strains 1A or DPQ1A was used to quantify the antibody response by ELISA method as described earlier (Kumar et al 2001). Briefly, the microtitration plates (maxisorp, Nunc) were coated with WCS antigen (10 lg/ml) in 0.05 M carbonate buffer (pH 9.6) and incubated at 37°C for 2 h. The plates were blocked with blocking buffer (PBS containing 1% w/ v BSA) for 1 h at 37°C followed by overnight incubation at 4°C.…”

Characterization of the Salmonella typhi Outer Membrane Protein C

“…The negative control was injected with 100 µl of PBS. Quantitation of antibodies was performed by ELISA [7]. All of the experiments with the animals were carried out in accordance with standard practice and the legal requirements of Iran.…”