Monoclonal antibodies were first produced by George Kohler and Cesar Milstein in 1975, and provided Stuart with the tools to unleash his subsequent research. The discovery led to a ‘gold rush’ of antibody research worldwide. However, Stuart had the special insights that identified key receptors such as CD2, CD3, CD4, CD5 and CD8, which are central to T cell immunity today. His antibodies were assigned identical CD numbers by the Human Leukocyte Differentiation Antigen Workshops, an international collaboration that he co-founded. Furthermore, his pioneering work catalyzed flow cytometry into a sophisticated investigative and diagnostic tool for immune pathologies.
Together with Ellis Reinherz, his laboratory described the first anti-human CD3 monoclonal antibody as well as clonotypic antibodies that defined clonal diversity among human T cells. Importantly, together with Cox Terhorst’s lab, they then characterized the multimeric human T cell receptor (TCR) complex. In addition, his lab developed the first anti-human CD4 monoclonal antibodies that were crucial in identifying the loss of this subset in individuals living with HIV. Then, with Reinherz and Stefan Meuer, Stuart outlined the human CD4 and CD8 link to helper and cytolytic functions, as well as restriction to HLA class II and I molecules, respectively. These concepts stand as fundamental cornerstones of immunology. He received numerous accolades, including induction into the National Academy of Sciences and the Robert Koch Award.
