title: Evaluation and characterisation of A and B fragments of Corynebacterium diphtheriae toxin towards recombinant diphtheria vaccine.
abstract: BACKGROUND
  Diphtheria is a highly communicable disease caused by toxin-producing strains of Corynebacterium diphtheriae.
  
  
  OBJECTIVE
  To evaluate the efficacy of A and B subunits of diphtheria toxin (DT-A, DT-B) as potential vaccines against C. diphtheriae. A culture of C. diphtheriae (strain PW 8) was grown on Loeffler plates while Lingood medium was used for production of diphtheria toxin (DT).
  
  
  METHODS
  DT was purified and digested to obtain pure DT-A and DT-B and detoxified to obtain diphtheria toxin. Four groups of mice were immunised with different antigens (Ag) of C. diphtheriae.
  
  
  RESULTS
  The antibody (Ab) titres were significantly increased with immunised groups subsequent to three injections. On the other hand, Ab titres were estimated after the three immunisations and the levels of different Ab isotypes were comparatively measured. The levels of various isotypes immune responses showed variation between immunised groups where the IgG subclasses were significantly increased mainly with DPT immunised group. The IgM and IgA were significantly increased with DT-A more than others. Additionally, the evaluation of the cellular immune responses demonstrated that spleen cells from DPT and DT-A groups gave highly significant proliferative response with production of high levels of IL-2 and IFN-γ (Th1/Th2). Separation and purification of DT gene were performed using polymerase chain reaction (PCR) and sub-cloned in pGEM-T vector, for further studying of recombinant vaccine.
  
  
  CONCLUSIONS
  Our results showed the possibility to prepare a potent recombinant vaccine containing whole DT gene or DT-A against C. diphtheriae or could be used in treatment of cancer as it give high levels of IL-2 and IFN-γ.
authors.affiliation: Department of Research and Development, VACSERA, Cairo, Egypt.
authors.forename: S
authors.initials: S
authors.lastname: Abulmagd
authors.forename: M
authors.initials: M
authors.lastname: Emara
authors.forename: S
authors.initials: S
authors.lastname: Aziz
authors.forename: R
authors.initials: R
authors.lastname: El-Domany
mesh_terms: D000818:Animals; D000907:Antibodies, Bacterial / Q000097:blood; D049109:Cell Proliferation; D003353:Corynebacterium diphtheriae; D004167:Diphtheria Toxin / Q000235:genetics / Q000276:immunology*; D004168:Diphtheria Toxoid / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D005260:Female; D007070:Immunoglobulin A / Q000097:blood; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D007371:Interferon-gamma / Q000378:metabolism; D007376:Interleukin-2 / Q000378:metabolism; D007963:Leukocytes, Mononuclear / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D021122:Protein Subunits / Q000235:genetics / Q000276:immunology; D013154:Spleen / Q000276:immunology; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D004167:Diphtheria Toxin; D004168:Diphtheria Toxoid; D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D007376:Interleukin-2; D021122:Protein Subunits; D014614:Vaccines, Synthetic; D007371:Interferon-gamma