One afternoon, Ullrich walked to the Immunology Division at Genentech. The division specialized in the creation of immunological molecules. Ullrich wondered whether someone in immunology might be able to design a drug to bind Her-2 and possibly erase its signaling. Ullrich had a particular kind of protein in mind—an antibody. Antibodies are immunological proteins that bind their targets with exquisite affinity and specificity. The immune system synthesizes antibodies to bind and kill specific targets on bacteria and viruses; antibodies are nature’s magic bullets.
