We use chemistry to understand immune diseases and to find solutions for situations where the immune system fails or is too active. We study the influence of cross-talk between immune pathways, chemical approaches to control and/or manipulate immune processes and rational approaches towards vaccine design. Our research provides new insights on how to harness the strength of immune system in order to: (i) expand the therapeutic arsenal to fight infections with next-generation vaccines, (ii) establish novel therapeutic modalities for treatment of cancer, and (iii) unravel the mechanism of immunotoxicity of compounds and environmental pollutants.