Toll-like receptors (TLRs) play important roles in the immune responses against invading microorganisms. Development of TLR antagonists is recognized as a promising direction in suppressing the associated inflammatory reactions of the TLRs. Aptamers are single-stranded RNA or DNA molecules isolated through an in vitro selection process. Using a novel molecular evolution strategy that combines immunoprecipitation (IP) with systematic evolution of ligands by exponential enrichment (SELEX)