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Background: Anthrax is a common disease among human and livestock which is caused by Bacillus anthracis. Bacillus anthracis has two strong immunogenic proteins: Protective antigen (PA) and lethal factor domain I (LFD1) that have always been considered as vaccine candidates against Bacillus anthracis. The aim of this study is to express and purify the lethal factor domain I (LFD1) in Escherichia coli and produce polyclonal antibody against it in mice. Materials and Methods: In this experimental study, LFD1 gene was amplified with BamH I and Xho I restriction site by PCR. After isolation, the gene was cloned to the expression vector pET28a (+). This vector was transformed to E. coli-BL21 (DE3) PLysSto to express LFD1 gene. The expression of LFD1 gene was induced by IPTG. After protein purification by affinity chromatography, the produced antigen was injected into mice for four times. Then the produced polyclonal antibody in mice serum was evaluated. Results: The cloned LFD1 gene in pET28a (+) vector was confirmed by PCR, enzymatic analysis, and sequencing. The expressed and purified recombinant protein was confirmed by SDS-PAGE and Western blotting. Finally, the isolated polyclonal antibody from mice serum was evaluated and confirmed by ELISA test. Conclusion: Noticing the appropriate expression, easy purification of LFD1, and the titer of produced polyclonal antibody against LFD1 in mice due to its immunogenicity, it can be considered as a good vaccine candidate against anthrax.

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Background: Shigellosis is a major global issue of human health. To date, no effective vaccine has been found against Shigella. One of the major virulent factors in Shigella dysenteriae type 1 is Shigella enterotoxin or STx. STxB has immunogenic, adjuvant, or carrier properties. Vaccine candidate antigens can be coupled with this adjuvant for production of an appropriate vaccine. IpaD has a key role in invasion, virulence, and infection by Shigella.

Materials and Methods: In this study, the gene sequences of STXB and ipaD were obtained from gene bank and corresponding genes were prepared as synthetic construct and then transferred to E. coli BL21DE3. By PCR amplification and enzymatic digestion, protein expression levels were assessed. Its protein expression was confirmed by Western blot technique. After extraction by affinity chromatography, the recombinant protein was injected four times to guinea pigs. The pigs were, then, challenged by Shigella felexneri 2a and active toxin of E. coli O157:H7.

Results: The results showed that groups of guinea pigs challenged with 28×LD₅₀ of  toxin  completely survived. Furthermore, guinea pigs were challenged by inducing Shigella felexneri 2a in their eyes. The results showed that the control pigs got cataracts, whereas the immune pigs were in health.

Conclusion: The findings of this study suggest that this recombinant protein is a good candidate for production of a recombinant vaccine against Shigella family.

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Background: Giardiasis is the most common infectious diseases of medical parasitology and public health in our country and in many countries is important. Accourding the importance of treating the disease, particularly parasite resistance to drugs. Thus, the aim of present study was investigated the effect of gold nanoparticles on Giardia lamblia cyst stage of the in vitro.

Materials and Methods: In this experimental study, Giardia cysts from contaminated fresh feces were collected and concentrated with use 0.85 M sucrose methods for isolation of cysts. Samples after counting with Noubar slide were stored at 4°C. The gold nanoparticles at concentrations of 0.05, 0.1, 0.3 mg/ml prepared and verified, the particle size was determined. The effect of different concentrations of the nanoparticles at 5, 15, 30, 60 and 180 minutes was evaluated and compared to control groups (metronidazole). Data from the study were recorded and analyzed with T-test and Chi-square by used SPSS software.

Results: The results of the cytotoxic effect of nanoparticles on the different concentration and time of Giardia lamblia cysts in vitro compared with the positive control (Metronidazole) shows mean percent of effect gold nanoparticles increased with increasing concentration and exposure time, so that the concentration of 0.3 mg/ml from 62% at 5 min to 96% at 180 min increased (p<0.05). Also, the survey results show Giardia cysts with increasing exposure time , killing effect of gold nanoparticles at a concentration of 78% in 0.05 mg/ml to 96% at a concentration of 0.3 mg/ml greatest increased (p<0.05). As a result, the concentration of gold nanoparticles in comparison with Metronidazole has the most effect gold nanoparticles at a concentration of 0.3 mg/mL, almost the same effect of Metronidazole as the drug of choice in the treatment of Giardia lamblia.

Conclusion: Therefore, the results of this study, gold nanoparticles at a concentration of 0.3 mg/ml as an effective combination for killing Giardia lamblia cysts in vitro can be used. Thus, future studies on laboratory animals (In vivo) are recommended.

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Background: Shigella dysenteriae one of the main causes of diarrhea in humans, but there is no vaccine against it. IpaD protein is one of the most important virulence factors in pathogenic shigella. The cloning N-terminal ipaD genes with ctB genes that have a role in adjuvant and carrier as recombinant vaccine can caused enhance the mucosal immune response.

Materials and Methods: Designing primers for genes ctB and ipaD were carried out based on the construction of gene cassettes, respectively. PCR reactions were performed to amplify the fragments and amplified fragments were cloned into pGEM-Teasy vector. Both the vector cut by restriction enzymes HindIII and XhoI and ipaD gene to gene ctB finally were Fusion. The ctB-ipaD gene cassette and expression vector pET28a(+) cuted by SalI and HindIII restriction enzymes. The cloning ctB-ipaD cassette was performed in the expression vector and expression of gene cassettes.

Results: In this study, the N-terminal ipaD as vaccine candidate antigen was genetically linked to the C terminal of ctB which has a carrier and adjuvant role. Fusing ctB-ipaD in the expression vector pET28a(+) is confirmed by sequencing, PCR and digested with restriction enzymes. The recombinant proteins produced is confirmed by SDS-PAGE and Western blot.

Conclusion: According to previous and similar studies, product cassette ctB-ipaD and expression its was expected. Is hoped to protein expression of this gene cassette and the production of antibodies could be achieved the candidate vaccine against Shigella.