title: Evaluation of the non-toxic mutant of the diphtheria toxin K51E/E148K as carrier protein for meningococcal vaccines.
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.
authors: GSK Vaccines, Research, Via Fiorentina 1, Siena 53100, Italy.
authors: S
authors: S
authors: Pecetta
authors: Department of Chemistry, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom.
authors: B
authors: B
authors: Vijayakrishnan
authors: GSK Vaccines, Research, Via Fiorentina 1, Siena 53100, Italy.
authors: M R
authors: MR
authors: Romano
authors: GSK Vaccines, Research, Via Fiorentina 1, Siena 53100, Italy.
authors: D
authors: D
authors: Proietti
authors: GSK Vaccines, Research, Via Fiorentina 1, Siena 53100, Italy.
authors: P
authors: P
authors: Lo Surdo
authors: GSK Vaccines, Research, Via Fiorentina 1, Siena 53100, Italy.
authors: C
authors: C
authors: Balocchi
authors: GSK Vaccines, Research, Via Fiorentina 1, Siena 53100, Italy.
authors: E
authors: E
authors: Mori
authors: Department of Chemistry, Chemistry Research Laboratory, Mansfield Road, Oxford OX1 3TA, United Kingdom.
authors: B G
authors: BG
authors: Davis
authors: GSK Vaccines, Research, Via Fiorentina 1, Siena 53100, Italy. Electronic address: francesco.x.berti@gsk.com.
authors: F
authors: F
authors: Berti
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D001426:Bacterial Proteins / Q000276:immunology; D004167:Diphtheria Toxin / Q000096:biosynthesis / Q000276:immunology*; D004337:Drug Carriers / Q000737:chemistry*; D004926:Escherichia coli / Q000378:metabolism; D005260:Female; D056724:Immunity, Humoral; D022401:Meningococcal Vaccines / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D011817:Rabbits; D058248:Serum Bactericidal Antibody Assay; D018074:Vaccines, Conjugate / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D004167:Diphtheria Toxin; D004337:Drug Carriers; D022401:Meningococcal Vaccines; D018074:Vaccines, Conjugate; C028581:CRM197 (non-toxic variant of diphtheria toxin)
keywords: CRM(197); Conjugate vaccines; DT-K51E/E148K; Diphtheria toxin mutant; Meningococcal vaccines