Evaluation of the non-toxic mutant of the diphtheria toxin K51E/E148K as carrier protein for meningococcal vaccines. Issue 11 (8th March 2016)

• Record Type: Journal Article
• Authors: Pecetta, S.; Vijayakrishnan, B.; Romano, M.R.; Proietti, D.; Surdo, P. Lo; Balocchi, C.; Mori, E.; Davis, B.G.; Berti, F.
• Is Part Of: Vaccine. Volume 34:Issue 11(2016)
• Page Start: 1405
• Page End: 1411
• Publication Date: 2016-03-08
• Subjects: Conjugate vaccines -- Meningococcal vaccines -- CRM197 -- Diphtheria toxin mutant -- DT-K51E/E148K; Vaccines -- Periodicals; 615.372
• DOI: 10.1016/j.vaccine.2016.01.040
• Languages: English
• ISSNs: 0264-410X

Abstract

Abstract: Diphtheria toxin mutant CRM197 is a common carrier protein for glycoconjugate vaccines, which has been proven an effective protein vector for, among others, meningococcal carbohydrates. The wide-range use of this protein in massive vaccine production requires constant increase of production yields and adaptability to an ever-growing market. Here we compare CRM197 with the alternative diphtheria non-toxic variant DT-K51E/E148K, an inactive mutant that can be produced in the periplasm of Escherichia coli . Biophysical characterization of DT-K51E/E148K suggested high similarity with CRM197, with main differences in their alpha-helical content, and a suitable purity for conjugation and vaccine preparation. Meningococcal serogroup A (MenA) glycoconjugates were synthesized using CRM197 and DT-K51E/E148K as carrier proteins, obtaining the same conjugation yields and comparable biophysical profiles. Mice were then immunized with these CRM197 and DT-K51E/E148K conjugates, and essentially identical immunogenic and protective effects were observed. Overall, our data indicate that DT-K51E/E148K is a readily produced protein that now allows the added flexibility of E. coli production in vaccine development and that can be effectively used as protein carrier for a meningococcal conjugate vaccine.