The Changes In The Gene Expression Pattern Of TCR-CD3 Complex In The Peripheral Blood Of Workers Exposed To Mercury

Objective:To analyze the changes in the gene expression pattern of TCR-CD3 complex in the peripheral blood of workers exposed to mercury, for evaluating the influence of mercury on T cell immunity. The study is expected to provide new data to further prevent damage on T cells immune function in workers exposed to mercury.Methods:The distribution of TCR Vp subfamily genes were analyzed in peripheral blood mononuclear cells (PBMCs) from 15 cases of workers exposed to mercury by using RT-PCR technique. Using real time quantitative RT-PCR with SYBR Green I technique, the expression levels of CD3γ, CD3δ, CD3εand CD3ζgenes were detected in PBMCs. Theβ2-microglobulin gene (β2M) was used as an endogenous reference, and the evaluation of each CD3 genes were used by the 2-△Ct×100% method. Peripheral blood samples from 15 healthy and non-occupational hazards of adult as controls.Result:Fifteen to 23 TCR Vβsubfamilies were detected in 15 samples from mercury exposure group. The expressed Vp subfamily number was significantly lower than those from healthy group (P= 0.000). The trend of distribution of the TCR Vβsubfamily in workers exposed to mercury was similar in different cases. Vβ6 could not be detected in all samples, lower expression frequency was found in Vβ16 (20%), Vβ12 (33%) and Vβ4 (40%). The relative mRNA expression levels of CD3γ,CD38δ,CD3ε,CD3ζgenes in mercury exposure group were 13.40%, 1.36%, 20.44% and 1.32%(median), respectively. In compared with control group (CD3γ:6.10%, CD3δ:0.83%, CD3ε:4.15%, and CD3ζ:2.53%), the relative mRNA expression levels of CD3γand CD3εchain in mercury exposure group were upregulated (P<0.05), while the expression level of CD3ζwas reduced (P<0.05), and there was not significant changed of the expression level of CD38 between the mercury exposure group and the control group (P= 0.059). By spearman rank correlation statistical analysis, the relative mRNA expression of CD3ζdidn't show the association with the other three genes in mercury exposure group, while positive correlation of the expression level was found between CD3y, CD3δand CD3εgenes (rs=0.886, P=0.000, rs=0.961,P=0.000, rs=0.909, P=0.000). The expression pattern of four CD3 genes were CD3ε> CD3γ> CD3ζ> CD3δin both groups. There was not significant differenct in the correlation of the changes of TCR-CD3 complex and urinary mercury concentrations, duration of mercury exposure and age in mercury exposure group (P>0.05).Conclusion:It is the first report providing the data of gene expression pattern of TCR-CD3 complex in the PBMCs in workers exposed to mercury. Selected expression of Vβrepertoire and the change of expression level of CD3 genes might be relate to impact of T cell immune in workers exposed to mercury.