Mackaness' original article about cellular resistance to infection, published in 1962, is recalled. These experiments laid the foundation of the analysis of immune mechanisms against infection with facultatively intracellular microorganisms. Based on a simple murine model with Listeria monocytogenes, an array of data was compiled during three decades, clarifying the mechanism of inborn resistance and acquired immunity to this type of parasites. The idea of various immune cell populations cooperating via cytokines was developed and experimentally proven. Different forms of immunodeficiencies were conceived in the same model, and therapeutic approaches were evaluated. Thus, thirty years after the first publication, Mackaness' concept of cell-mediated immunity to infection is solidly based on experimental data, and is an integral part of our understanding of the mammal immune system.