 With Paul M. Allen, Ph.D., the Robert L. Kroc Professor at Washington University School of Medicine, Unanue discovered that peptides from foreign antigens were bound to a group of molecules known as the major histocompatibility complex (MHC).This peptide-MHC complex was shown to be recognized by T cells.Although the latter hypothesis was initially greeted with intense skepticism, a large body of work, generated over the last two decades, has confirmed its validity.