Toll-like receptor regulation of effector T lymphocyte function

• TLRs regulate CD4+ T cell inflammatory function.
• TLRs are evolutionarily-conserved mechanisms for T cell co-stimulation.
• Innate-like T cells are subject to functional regulation by TLR signaling.

The landmark discovery of pattern-recognition receptors, including Toll-like receptors (TLRs), furthered our understanding on how the host rapidly responds to invading pathogens. For over a decade now, extensive research has demonstrated the crucial role of multiple TLRs in the detection of a broad range of molecules expressed by microbial pathogens as well as host-derived danger signals. TLR activation is the hallmark of the innate immune response. Recent evidence, however, demonstrates that cells of the adaptive immune response use these innate signaling pathways as well. This review discusses recent findings regarding TLR functionality in T lymphocytes with a specific emphasis on the promotion of T helper cell-dependent inflammation through direct TLR signaling.