Expression, extraction, purification and immunogenicity study of three recombinant proteins LTB, THc, BoNT / A and Comparison of produced antibody titer against them in laboratory animals

Among the bacterial agents, the most common cause of diarrheal disease is Entrotoxigenic Escherichia coli. Lebal toxin B (LTB) subunit of LT toxin could induce six-month immunity. Tetanus toxin of Clostridium tetani causes the fatal disease, tetanus. Tetanus can be prevented by vaccination with tetanus toxoid. This toxoid induces ten years immunity in humans. Binding domain of tetanus toxin (THc), of the toxoid is considered as immunogenic part of tetanus toxin. Clostridium botulinum causes botulism disease. The protectional effect of this toxoid is only two years against this disease. It seems that the immunogenicity potency of these three subunits may influence on the memory longevity. The aim of this study is the assessment of LTB, BoNT/A and THc immunogenicity in mouse. The transgenic E. coli BlDE3 with pET28a vector, containing recombinant ltb, thc and bont/A-Hc genes separately were used for expression of recombinant proteins. All mentioned proteins were derived, purified and evaluated on SDS-PAGE gel. Finally, mice immunization were carried out and antibody titration of all recombinant proteins were evaluated and compared using t-Test in SPSS software. The result of SDS-PAGE gel evaluation showed a proper expression. The immunoassay results of serum showed that the antibody titer against the recombinant protein of THc was higher than those for the recombinant protein of BONT/A-Hc and LTB. A difference in antibody titer also was observed between two proteins i.e. BoNT/A-Hc and LTB (P value <.0001). The differences in the antibody titer may be related to the longevity of memory cells. However, the result needs more studies