Cholera toxin B subunit as a carrier protein to stimulate a mucosal immune response.
Horseradish peroxidase (HRP) was covalently coupled to the binding subunit of cholera toxin (CTB) via a two-step glutaraldehyde procedure. The HRP-CTB conjugate was characterized by physiochemical as well as immunochemical methods. Mice were immunized intraduodenally with the HRP-CTB conjugate, with HRP alone, or with a mixture of uncoupled CTB and HRP. The functionally active dose of CTB was 50 micrograms and the HRP dose was in the 30- to 90-micrograms range. Both IgA and IgG antibody responses were measured in serum, intestinal washes, and bile by using a solid phase immunoradiometric assay. Mice immunized with the HRP-CTB conjugate showed a significantly higher level of IgA anti-HRP in intestinal washes and bile, as well as increased levels of serum IgG anti-HRP. Animals that received only HRP or the mixture of CTB and HRP had reduced levels of HRP-specific antibody of either class in both gut washes and bile. The IgA anti-HRP responses in the gut washes were 33- to 120-fold higher when the conjugate was used as the immunogen in comparison with immunization with the CTB + HRP or the HRP alone. Vaccines to stimulate mucosal immunity to any antigenic determinant might thus be prepared by covalent conjugation to effective mucosal immunogens such as CTB.
D000818:Animals; D000917:Antibody Formation; D000941:Antigens / Q000008:administration & dosage*; D002352:Carrier Proteins / Q000008:administration & dosage / Q000032:analysis / Q000276:immunology*; D002772:Cholera Toxin / Q000008:administration & dosage / Q000032:analysis / Q000276:immunology*; D004386:Duodenum; D005260:Female; D006735:Horseradish Peroxidase / Q000008:administration & dosage / Q000032:analysis / Q000276:immunology; D007114:Immunization / Q000379:methods; D007413:Intestinal Mucosa / Q000378:metabolism*; D051379:Mice; D008815:Mice, Inbred Strains; D011817:Rabbits
D000941:Antigens; D002352:Carrier Proteins; D002772:Cholera Toxin; D006735:Horseradish Peroxidase