Philippa Marrack: Investigator, Howard Huges Medical Institute Professor, Integrated Department of Immunology, National Jewish Health, Denver, Colorado; Distinguished Professor, University of Colorado Health Sciences CenterDAVID X. TEJADA
Sometimes the experimental controls spit out the most interesting results. In the early 1980s, Philippa “Pippa” Marrack and her lab partner (and husband) John Kappler were investigating how, exactly, macrophages process antigens so they can be recognized by T cells. “We knew that macrophages have to chew antigens up into little pieces before the T cell can see them,” says Marrack. “The question was: ‘what’s special about the way that macrophages are doing this chewing?’ ” So a student in the lab served macrophages some ovalbumin to munch. As a control, he cut up the same protein using trypsin—a digestive enzyme that dices proteins into pieces. To his surprise, the trypsin-minced material “worked like crazy,” says Marrack. It turned on T cells as well as ...
