Background:The potential of plants, as a safe and eukaryotic system, is considered in the production of recombinant therapeutic human protein today; but the expression level of heterologous proteins is limited by the post-transcriptional gene silencing (PTGS) response in this new technology. The use of viral suppressors of gene silencing can prevent PTGS and improve transient expression level of foreign proteins. In this study, we investigated the effect of p19 silencing suppressor on recombinant human nerve growth factor expression in Nicotiana benthamiana. Materials and Methods: The p19 coding region was inserted in the pCAMBIA using NcoI and BstEII recognition sites. Also, the cloned synthesized recombinant human NGF (rhNGF) fragment was cloned directly into PVX vector by ClaI and SalI restriction enzymes. The co-agroinfiltration of rhNGF with p19 viral suppressor of gene silencing was evaluated by dot-blot and SDS-PAGE. The amount of expressed rhNGF protein was calculated by AlphaEaseFC software. Results: Co-agroinfiltration of hNGF with P19 suppressor showed about fortyfold increase (8% total soluble protein (TSP)) when compared to the absence of P19 suppressor (0.2%TSP). Conclusion:The results presented here confirmed that the use of P19 gene silencing suppressor derived from tomato bushy stunt virus (TBSV) could efficiently increase the transient expression of recombinant proteins in Nicotiana benthamiana manifold.

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Background: The most common primary cause of liver cancer is hepatocellular carcinoma (HCC). Cytokines as mediators have significant roles in immune and inflammatory responses. Interleukin-13 (IL-13) is a potent pleiotropic cytokine. Objectives: The aim of this study was to evaluate the association of IL-13/+110 gene polymorphism in patients with chronic hepatitis B virus (HBV), one of the most important factors that lead to the development of HCC. Methods: DNA was extracted from peripheral blood cells of all 585 participants including 302 unrelated Hepatitis B surface antigen (HBS-Ag) positives and 283 healthy matched groups. The IL-13 gene polymorphism (+ 110 A or G) was genotyped by SSP-PCR method and then genotype frequencies were checked by using the Pearson's chi-square test and/or Fisher exact test. Results: The frequencies of A/G genotype (CI = 1.18-2.34, OR = 1.66, P = 0.004) and A/A genotype (CI = 0.95-3.53, OR = 1.84, P = 0.071) were higher in the patients. Also, the frequency of A allele was remarkably higher in the HBV patients than control group (CI = 1.09-1.79, OR = 1.84, P = 0.071). Conclusions: High frequency of A allele in patients rather than control group suggested that A allele probably plays a role in augmenting susceptibility to HBV infection risk and high frequency of G allele in controls suggested this allele has a protective role in this disease.