Project description:Introduced for mass immunization in the 1920s, vaccines against diphtheria are among the oldest and safest vaccines known. The basic principle of their production is the inactivation of purified diphtheria toxin by formaldehyde cross-linking, which converts the potentially fatal toxin in a completely harmless protein aggregate, which is still immunogenic. Since in addition to diphtheria toxin also other proteins may be secreted by Corynebacterium diphtheriae during cultivation, we assumed that diphtheria toxoid might not be the only component present in the vaccine. In this study, we established a protocol to reverse formaldehyde cross-linking and carried out mass spectrometric analyses. Different secreted, membrane-associated and cytoplasmic proteins of C. diphtheriae were detected in several vaccine preparations from across the world. Western blot analyses indicated that at least some of these are immunogenic and may therefore support protection against C. diphtheriae. In frame of this study, we could show that the C. diphtheriae toxoid vaccines also induce antibodies directed against diphtheria toxin secreted by Corynebacterium ulcerans, an emerging pathogen which is outnumbering C. diphtheriae as cause of diphtheria-like illness in Western Europe, but do not induce immune reaction against other C. ulcerans proteins.
Project description:Diphtheria toxoid vaccines are among the oldest and safest vaccines known. The basic principle of production is the inactivation of purified diphtheria toxin by formaldehyde cross-linking, which converts the potentially fatal toxin in a completely harmless protein aggregate, which is still immunogenic. Since in addition to diphtheria toxin also other proteins might be secreted by Corynebacterium diphtheriae, we assumed that diphtheria toxoid might not be the only component present in the vaccine. Therefore, we established a protocol to reverse formaldehyde cross-linking and carried out mass spectrometric analyses. Different secreted, membrane-associated and cytoplasmic proteins of C. diphtheriae were detected in several vaccine preparations from across the world. Western blot analyses indicated that these are immunogenic and may therefore support protection against C. diphtheriae. Furthermore, we could show that the vaccines also induce antibodies directed against diphtheria toxin secreted by Corynebacterium ulcerans, an emerging pathogen evoking diphtheria-like illness and skin infections.
