One hundred years ago the birth of immunology was made official by the Nobel Prize award to Elie Metchnikoff and Paul Ehrlich. Metchnikoff discovered phagocytosis by macrophages and microphages as a critical host-defense mechanism and thus is considered the father of cellular innate immunity. Ehrlich described the side-chain theory of antibody formation and the mechanisms of how antibodies neutralize toxins and induce bacterial lysis with the help of complement and thus is considered one of the fathers of humoral adaptive immunity. Despite many discordant discussions in the initial phase after these discoveries, innate and adaptive responses are now known to be complementary partners in producing robust immunity.