Brian has a long-standing interest in the development of immunological memory. As an undergraduate at the University of Pennsylvania, Brian investigated mechanisms underlying the development of broadly protective immunity against the influenza virus. He then moved to Yale University for graduate school, where he examined how CD4 T cells regulate the development of memory CD8 T cell following viral infection. As a postdoctoral fellow at the University of California, San Francisco, Brian was the first to characterize memory B cell precursor cells. He then developed the first in vivo method to screen factors regulating the development of memory B cells and was able to use this method to identify novels regulators of memory B cell development.