Luciferase reporter activity of TLR9 (promoter-intron) plasmid constructs. a), schematic of four reporter gene constructs that contains TLR9 promoter- intron region with TTA, CCG, CTG and TCG at position −1486, -1237, and +1174 polymorphic sites, respectively. b), luciferase expression of the four constructs in THP-1 cells and pGL4.10 as negative control. The luciferase activity levels are mean values of three (3) independent experiments that were all carried out in triplicate. Anova test and t-test were used to test for statistical significance. P value of <0.05 was considered to be statistically significant.