Regulation of Immune Activation by Optical Control of TLR1/2 Heterodimerization

The activation of toll‐like receptors (TLRs) plays important roles in the immune response. The ability to control the activities of TLRs could be usable as a switch for immune response. Here we have rationally designed and synthesized a photoswitchable Pam3CSK4 derivative—P10—to control the activation of TLR1/2. The ground‐state trans‐P10 was able to stimulate and activate antigen‐presenting cells (APCs) by promoting TLR1/2 heterodimerization. However, cis‐P10, derived from UV irradiation of trans‐P10, reduced the activities of APCs by impeding the TLR1/2 heterodimerization. In the absence of UV radiation, the cis‐P10 slowly returned to its ground trans state, restoring the activities of the APCs stimulation. Our results indicated that optical control of TLR1/2 heterodimerization mediated by the photoswitchable P10 offers the potential to regulate immune activation and inflammation. Reduction of systemic inflammation without immune system inhibition: A photoswitchable ligand for regulation of immune activation through optical control of the heterodimerization of toll‐like receptors 1 and 2 (TLR1/2) has been developed, offering the potential to regulate immune activation and inflammation.