title: Induction of antigen-specific immune responses by oral vaccination with Saccharomyces cerevisiae expressing Actinobacillus pleuropneumoniae ApxIIA.
abstract: An effective way of inducing both mucosal and systemic immune responses to protect against Actinobacillus pleuropneumoniae serotype 2 Korean isolate was examined in mice by oral immunization using Saccharomyces cerevisiae expressing the ApxIIA protein. The immunogenicity of the yeast-derived ApxIIA antigen was confirmed by the challenge test and ApxIIA-specific IgG antibody response assay. The group subcutaneously immunized with the protein extracted from the yeast expressing ApxIIA showed a higher survival rate after challenging with A. pleuropneumoniae serotype 2 isolate and IgG antibody level in serum than the group injected with that prepared from the yeast harboring vector only. Feeding the yeast expressing ApxIIA to mice induced both systemic and mucosal immune responses against the antigen. ApxIIA-specific IgA antibody titers and the number of IgA-secreting cells of mice vaccinated with S. cerevisiae expressing ApxIIA dose-dependently increased from the third immunization in both intestine and lung (P<0.01). A similar tendency of ApxIIA-specific IgG antibody responses was observed in the sera. The protective efficacy of the oral immunization was then evaluated by a challenge with a minimal lethal dose (MLD, 4.5 x 10(7) CFU/ml) of the A. pleuropneumoniae serotype 2 isolate. Fifty percent of the 30 mg administered group and 30% of the 15 mg administered group survived while none of the mice in the control groups survived after 36 h. These results suggest that feeding animals the yeast expressing the antigen can be an effective strategy to induce protective immune responses against A. pleuropneumoniae infection.
authors.affiliation: Department of Infectious Diseases, College of Veterinary Medicine and School of Agricultural Biotechnology, Seoul National University, Seoul 151-742, Republic of Korea.
authors.forename: Sung Jae
authors.initials: SJ
authors.lastname: Shin
authors.forename: Jong Lye
authors.initials: JL
authors.lastname: Bae
authors.forename: Young-Wook
authors.initials: YW
authors.lastname: Cho
authors.forename: Deog Yong
authors.initials: DY
authors.lastname: Lee
authors.forename: Dae-Hyuk
authors.initials: DH
authors.lastname: Kim
authors.forename: Moon-Sik
authors.initials: MS
authors.lastname: Yang
authors.forename: Yong-Suk
authors.initials: YS
authors.lastname: Jang
authors.forename: Han Sang
authors.initials: HS
authors.lastname: Yoo
mesh_terms: D000189:Actinobacillus Infections / Q000517:prevention & control*; D016977:Actinobacillus pleuropneumoniae / Q000276:immunology*; D000284:Administration, Oral; D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood*; D001426:Bacterial Proteins / Q000235:genetics / Q000276:immunology*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000276:immunology*; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005798:Genes, Bacterial; D006460:Hemolysin Proteins; D007070:Immunoglobulin A / Q000097:blood; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D007074:Immunoglobulin G / Q000097:blood; D007422:Intestines / Q000276:immunology; D008168:Lung / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D016019:Survival Analysis; D014611:Vaccination; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; C085361:ApxII toxin, bacteria; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D004269:DNA, Bacterial; D006460:Hemolysin Proteins; D007070:Immunoglobulin A; D007071:Immunoglobulin A, Secretory; D007074:Immunoglobulin G; D014614:Vaccines, Synthetic