pLTA regulated rhTNF-α-mediated receptor expression. (A) HT-29 cells were treated with 100 μg/ml of pLTA for 20 h followed by 50 ng/ml of rhTNF-α for 6 h. Treatment with rhTNF-α or pLTA alone was used as control. After extracting total RNA, cDNA was synthesized and PCR was performed with specific primers for TLR2, CD14, TNFRSF1A, TNFRSF1b, and GAPDH (upper and lower panel). (B) HT-29 cells were pretreated with anti-TLR2, -CD14, or control IgG for 30 min and then restimulated with 50 ng/ml of rhTNF-α for 24 h. IL-8 expression was analyzed from culture supernatants by ELISA. Data are given as means ± standard deviations for triplicate samples in a single experiment. *, p < 0.05. (C) HT-29 cells were treated with 100 μg/ml of pLTA for 20 h following anti-TLR2 antibody treatment for 30 min and then restimulated with 50 ng/ml of rhTNF-α for 6 h. After total RNA extraction and cDNA synthesis, the TNFRSF1A mRNA level was amplified by PCR using specific TNFRSF1A primers (upper panel). The TNFRSF1A mRNA quantity was normalized with GAPDH after density analysis using Image J software (lower panel). At least 3 different experiments were conducted. UT indicates untreated cells.