TLR3 expression in human NB cell lines. (A) Quantitative RT-PCR analysis of TLR3 mRNA level in three NB cell lines. (B) Western blot analysis of TLR3 protein level in three NB cell lines. Top panel, immunoblot analysis of TLR3 expression in three NB cell lines. Bottom panel, quantification results of TLR3 protein level were mean ± SD of triplicate experiments. **: P < 0.01.