Dr. Kwok's research projects are focused on understanding the behavior of human “helper” T cells. These cells are difficult to detect and isolate using traditional methods, but can be studied effectively using tetramers: synthetic protein conjugates that can be used to directly label T cells. These novel tetramer reagents provide a new approach for studying healthy immune responses directed against viruses and other pathogens and harmful immune responses that are the underlying cause of autoimmune diseases and allergy. Detailed studies using tetramers have increased our understanding of the biochemical patterns that activate the immune system. Knowledge of this kind will be critical for developing improved vaccines and targeted therapies to combat infectious diseases, allergy, autoimmunity and cancer.