title: Analysis of immune response in young and aged mice vaccinated with corn-derived antigen against Escherichia coli heat-labile enterotoxin.
abstract: Enterotoxigenic strains of Escherichia coli produce a heat-labile holotoxin (LT), which causes diarrhea. We engineered corn seeds to produce LT-B, the nontoxic subunit of LT, to serve as a plant-derived vaccine to traveler's diarrhea and as an adjuvant for co-administered proteins. We previously demonstrated that a strong mucosal and systemic antibody response is elicited in young mice with oral administration of corn-derived LT-B. The present study examined systemic and mucosal antibody responses to LT-B in young and aged mice, and recall responses to oral administration and injection of LT-B in aged mice. Specific IgA and IgG antibodies were detectable during an 11-mo period, although the concentration of antigen-specific antibodies declined gradually. Booster by feeding or injection dramatically increased the concentration of specific IgA from that seen in young mice. Specific IgG levels were boosted to concentrations similar to those in young mice. This effect may be age-dependent and related to prior immunization exposure. Analysis of the antibody response of naïve aged mice against corn-derived LT-B demonstrated an age-related suppression in specific IgG production, but not specific IgA. These results may provide important information for edible vaccine strategies for young and aged individuals.
authors.affiliation: Plant Transformation Facility, Department of Agronomy, Iowa State University, Ames, IA 50011, USA.
authors.forename: Sule
authors.initials: S
authors.lastname: Karaman
authors.forename: Joan
authors.initials: J
authors.lastname: Cunnick
authors.forename: Kan
authors.initials: K
authors.lastname: Wang
mesh_terms: D000284:Administration, Oral; D000367:Age Factors; D000818:Animals; D052179:Antigens, Plant / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D001427:Bacterial Toxins / Q000235:genetics / Q000276:immunology*; D002772:Cholera Toxin / Q000276:immunology; D004768:Enterotoxins / Q000235:genetics / Q000276:immunology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000276:immunology*; D005243:Feces / Q000737:chemistry; D005260:Female; D018928:Immunity, Mucosal / Q000276:immunology*; D007117:Immunization, Secondary; D007070:Immunoglobulin A / Q000097:blood / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007132:Immunoglobulin Isotypes / Q000097:blood / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D030821:Plants, Genetically Modified; D011994:Recombinant Proteins / Q000276:immunology*; D012639:Seeds / Q000737:chemistry / Q000235:genetics; D014611:Vaccination; D003313:Zea mays / Q000737:chemistry* / Q000235:genetics
chemical_list: D052179:Antigens, Plant; D001427:Bacterial Toxins; D004768:Enterotoxins; D029968:Escherichia coli Proteins; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D011994:Recombinant Proteins; D002772:Cholera Toxin; C027538:heat-labile enterotoxin, E coli