Background: Helicobacter pylori is the most common bacteria causing chronic infections worldwide. An important virulence factor of H. pylori is a vacuolating cytotoxin (VacA) that induces the formation of acidic vacuoles in cytoplasm and damage to epithelial cells. The aim of this study was to examine the antigenic properties of the recombinant VacA of H. pylori in infected sera of mice and human.

Materials and Methods: In this experimental study, the highly antigenic region of VacA gene (1233 bp) was detected by bioinformatics methods, and it was amplified by PCR method and cloned into the pET32a expression vector. After expression and purification of the target protein, its antigenicity was studied by Western Blotting using human sera infected with H. pylori and sera from immunized mice infected with purified recombinant VacA.

Results: PCR and sequencing results showed that the target gene was correctly cloned into the recombinant vector. Antibodies used in Western Blotting indicated the production and expression of the recombinant protein (65kDa) with concentration of 2.1 mg/ml.

Conclusion: Recombinant VacA protein has antigenic and immunogenic properties thus, it is a proper candidate for designing H. pylori vaccine and diagnostic kits

Background: Helicobacter pylori (H. pylori) is a gram negative bacilli that causes the stomach and duodenum diseases in human. An important virulence factor of H. pylori is a CagA gene that increases of colonization it in stomach epithelial cells and lead to inflammation and peptic ulcers. The aim of the present study was to production of recombinant protein containing highly antigenic region of CagA in E. coli.

Materials and Methods: In this experimental study, the antigenic region (1245 base pair) of CagA gene was detected by bioinformatics methods, proliferated by PCR method, digested by BamHI and XhoI restriction enzymes and cloned into pET32a plasmid and was expressed in the E. coli BL21 (DE3) pLysS with induced by IPTG. The expressed protein was purified with Ni-NTA kit and its antigenicity was studied by western blotting method.

Results: Data showed the successful cloning and expression of the target gene. Recombinant CagA protein purified by Ni-NTA kit and dialysis with concentration of 1.5 mg/ml. In western blotting, the produced protein was interacted with infected human and mice sera.

Conclusion: Results indicated that recombinant CagA protein (65 KDa) maintains its antigenicity, so could be used for serological diagnosis of H. pylori diseases and production of vaccine.

Background: Delivery of antigens directly to dendritic cells enhances the immune responses to the antigen and is an attractive approach for eliciting cellular immune responses against mutagenic pathogens like HIV virus. So the aim of this study is evaluation of immune responses elicited by delivered multi-epitopic HIV-1 tat/pol/gag/env recombinant protein to dendritic cells in sito using &alphaDEC-205 mAb.

Materials and Methods: In this study, recombinant protein expressed by pET23a-HIVtop4 plasmid including HIVtop4 sequence (Gag158-186, Pol150-190, ENV296-323, ENV577-610, Tat1-20 and Tat44-61) in BL21 E. coli cells was used as vaccine model. To exploiting dendritic cells, properties for immunization purposes, we conjugated this recombinant protein chemically to anti body against DEC-205 receptor on these cells. Balb/c mice immunized subcutaneously (s.c.) with conjugated multi-epitopic protein or un-conjugated one (as control) simultaneously with Poly I: C as dendritic cell maturation factor. Lymphocyte proliferation was measured by bromo di uridine assay, Cytotoxicity by Grenzyme B production activity, IL-4, IL-17, IFN- cytokines production and total antibody by direct and indirect ELISA methods in order.

Results: Immunization by anti DEC-205 conjugated peptide led to a significant increase in the proliferative responses of lymphocytes, production of Gr-B, IFN-&gamma, IL-4 and IL-17 cytokines and total antibody titer in comparison with the none targeted groups.

Conclusion: It is concluded that targeting of protein antigens to DEC-205+dendritic cells significantly enhances immune responses in compare to non-targeting strategies.

Background: Nef is one of the HIV-1 critical proteins, because it is essential for viral replication and AIDS disease progression and induction of immune response against it can partially inhibit viral infection. Moreover, a domain of the HIV-1 Trans-Activator of Transcription (Tat, 48-60 aa) could act as a cell penetrating peptide (CPP). In current study, cloning and expression of Tat-Nef fusion protein was performed in E. coli for the first time. The protein expression was confirmed by western blot analysis and was purified using reverse staining method.

Materials and Methods: In this experimental study, primarily, cloning of Tat-Nef fusion gene was done in pGEX6p2 expression vector. Then, the expression of Tat-Nef recombinat protein in E.coli BL21 (DE3) strain was performed by using IPTG inducer. The protein expression was confirmed by SDS-PAGE and western blotting using anti-Nef monoclonal antibody. Then, the recombinant fusion protein was purified from gel using reverse staining method.

Results: The results of PCR analysis and enzyme digestion showed a clear band of ~ 726 bp in agarose gel indicating the correct Tat-Nef fusion cloning in pGEX6p2 prokaryotic expression vector. In addition, a 54 kDa band of Tat-Nef on SDS-PAGE revealed Tat-Nef protein expression that western blot analysis using anti-Nef monoclonal antibody confirmed it.

Conclusion: The purified Tat-Nef recombinant fusion protein will be used as an antigen for protein vaccine design against HIV infection.