Cynthia Baldwin has been an investigator in the area of cellular immunology for over 30 years. Her research has focused on cellular responses to bacterial and protozoan pathogens of humans and livestock including Brucella, Leptospira, Mycobacteria and Theileria. In addition, her research has emphasized the characterization and function of gamma delta T lymphocytes (γδ T cells) in the bovine model. With regard to the latter, she and her colleagues have demonstrated that expression of a family of novel pattern recognition receptors, known as the WC1 co-receptor family, by γδ T cells designates antigen reactivity, in conjunction with the T cell receptor, by binding pathogens and pathogen components directly. WC1 molecules are members of the scavenger receptor cysteine-rich (SRCR) superfamily and are highly related to the CD163 family. Gamma delta T cells stimulated in this manner have immunological memory and appear to be an important component in the response to leptospira vaccination that results in a pro-inflammatory (Th1) type immune response as well as to Mycobacteria bovis infection. These discoveries may influence the way we think about γδ T cells as players in adaptive immunity and potentially in vaccine development.