Toll-like receptor 3 is necessary for dsRNA adjuvant effects

Toll-like receptors (TLR) recognize pathogen associated molecular patterns, and the binding of their specific ligands triggers a proinflammatory response that helps to fight invading microorganisms, and can be harnessed to increase vaccine efficiency. The present study demonstrates that double-stranded RNA is a promising vaccine adjuvant able to increase both proliferation and activation of antigen specific CD8(+) T cells. Importantly, TLR3 is required for this adjuvant effect, as TLR3 deficient recipients failed to enhance proliferation of adoptively transferred TCR transgenic CD8(+) T cells in the presence of double-stranded RNA. Finally, this Study also shows that, in contrast to previous reports in humans, TLR3 does not exert direct costimulatory activity on CDS+ T cells in mice. (C) 2009 Elsevier Ltd. All rights reserved.