George Bellamy Mackaness (20 August 1922 – 4 March 2007) was an Australian professor of microbiology, immunologist, writer and administrator, who researched and described the life history of the macrophage.

After the Second World War he moved to London to study pathology before taking up a graduate post at Howard Florey's Laboratory in Oxford.

Shortly after returning to Australia, Mackeness was appointed acting head of the Department of Experimental Pathology at the John Curtin School of Medical Research (JCSMR), where his observations led him to describe "acquired cellular resistance" and that specifically committed T-cells reacting with antigen, activated the macrophages.

[1] Howard Florey offered Mackaness a job in his laboratory at the Sir William Dunn School of Pathology in Oxford.

[1] On returning to Australia, Mackeness moved to Canberra having been appointed to at first staff and then acting head of the Department of Experimental Pathology at the John Curtin School of Medical Research (JCSMR), an institution he saw being planned by Florey while in Oxford.

[2] He concluded that the macrophage response was dependent on the particular original infection and the findings were published in The Journal of Experimental Medicine in 1962 and 1964.

[6] His 1962 paper titled "Cellular Resistance to Infection", published in the Journal of Experimental Medicine, played a significant part in earning him a professorship in microbiology at the University of Adelaide.

[1] In 1965, he became director of the Trudeau Institute, where over the subsequent ten years he appointed and led staff on work relating to cell-mediated immunity to infection and, later, cancer.

[4] While at Squibb, the FDA had denied a license to the first ACE inhibitor, captopril, due the side effects being too unacceptable, particularly the risk of producing a severe low blood count.

[1] Mackaness persuaded the company to reduce the dose by half, resulting in FDA approval and significant profits for the Squibb.

[1] In 1945, after graduating, Mackaness married Gwynneth Patterson, an army nurse, who he met during the early years of the Second World War, whilst a medical student.