Preliminary Study Of Immune Response And Mechanism In Mice Induced By A Peptide Mimic From HCV HVR1

Hepatitis C virus (HCV) infection represents an important global health-care burden, which is likely to increase over the coming years. There are approximately 3–4 million new cases of HCV infection each year, and current estimates suggest that a minimum of 3% of the world's population (approximately 170 million people) are chronically infected, and are at risk of developing liver cirrhosis or hepatocellular carcinoma. The efficacy of current recommendation of pegIFN-αand ribavirin is abut 50%, which is very expensive for the patient in developing countries and not as satisfied as expected. The more efficacious and tolerable therapies are urgently required, particularly for the increasing proportion of patients who are refractory to treatment with IFN-αand ribavirin. Therefore therapeutic vaccine may be a good choice for HCV patients, especially therapeutic peptide vaccine.According to envelop protein 2 of the HCVⅡ/1b,Ⅲ/2a virus strain in Chinese population, one peptide just including 7 amino acids was synthesized. After BALB/c mice were subcutaneously immunized by the synthesized peptide, the immune model and mechanism were investigated preliminarily.After immunization subcutaneously for three weeks, the mice splenocytes were harvested. The cell proliferation assay indicated that the splenocytes in experimental group proliferated more than the control. The types of mice splenocytes were detected by FACS while strained with different fluorescent antibodies. The values of CD8~+ and CD3~+ in the experimental group were higher than the control, while CD4~+ and CD19+ lower. The ratio of CD4~+/CD8~+ was lower than control and CD3~+/CD19+ lower. The levels of IFN-γ, IL -10 and IL -2 secreted by the immunized splenocytes were higher than control through ELISPOT.The chip of affymetrix mouse genome 430 2.0 assay was used in order to analyze the model and mechanism, which included 39000 transcripts standing for 34000 mice genes according to Genebank, dbEST, RefSeq and UniGene database. The different expressed levels of genes were detected through cluster analysis and bioinformatics assay. The levels of gene Gp1bb,Hp,F13a1,F2rl2,Gp5,F10,Vwf were higher than control, while lower gene levels of Tnfrsf13c,Syk, Tcrb-V13,Fgd4,Igh-6,Pde4b,Socs3,Jak1,Tnfsf13b,Cd4 on the other hand. The mRNA levels of syk, cd4, socs3, TNF-αwere lower than control by RT-PCR assay. The protein levels of CD4 and SOCS3 were lower than control by Western Blot assay.In conclusion, the peptide could induce cell-mediated immune response through CD8~+ T cells while the inflammation was inhibited through some factors such as SOCS3, TNF-α, Syk.