The fluorescent quantitative real-time PCR standard curve of UL45. The x-axis represented ten-fold dilutions of PMD18-T/UL45 plasmids, and the y-axis represented corresponding cycle threshold (Ct) values. Each dot represents the result of triplicate amplification of each dilution. The standard curve equation is Y = -3.366 × +8.995. The correlation coefficient and the slope value of the regression curve were indicated in the figure.