Two scientists who discovered the roles of key immune cells have won one of the 2019 Lasker medical-research awards — prizes often dubbed the American Nobels.

Immunologists Jacques Miller, at the Walter and Eliza Hall Institute of Medical Research in Melbourne, Australia, and Max Cooper, at Emory University in Atlanta, Georgia, will split the US$250,000 prize for basic medical research.

The duo identified T- and B-cells, which are key components in the immune system’s ability to recognize specific pathogens and cancer cells. B-cells produce antibodies — proteins that can recognize the molecular signatures of pathogens. T-cells form a key defence against virus-infected cells and cancer cells.

Miller, working at the University of London in the late 1950s and 1960s, identified a population of immune cells that develop in the thymus glands of mice — called T-lymphocytes or T-cells. He showed that mice lacking a thymus — an organ whose role was unknown — were prone to infection and did not reject skin grafts from other rodents.

Cooper built on Miller’s discovery, while at the University of Minnesota in Minneapolis in the 1960s. He determined that cells produced in an organ found in birds — called the bursa of Fabricius — were responsible for antibody production, and that their development was distinct from that of T-cells. Cooper and others later showed that humans and other mammals produce these B-lymphocytes, or B-cells, in their bone marrow.

Because of their ability to recognize — and block — most any molecule, antibodies have been successfully developed into medicines. Three scientists who helped develop an antibody drug used to treat certain breast cancers are winners of this year’s Lasker-DeBakey Clinical Medical Research Award. H. Michael Shepard, and Axel Ullrich, at the Max Planck Institute of Biochemistry in Martinsried, Germany, identified the gene, HER2 , that encodes the protein that the drug, called Herceptin, targets while at the biotechnology firm Genentech. Oncologist Dennis Slamon, at the University of California, Los Angeles, showed that some breast tumours had extra copies of HER2 and overproduced its protein product.

A third prize, the 2019 Lasker-Bloomberg Public Service Award was given to Gavi, the Vaccine Alliance. The Geneva-based non-governmental organization raises funds to pay for vaccines in low and middle-income countries. The organization has helped vaccinate 760 million children in 73 countries. Last month, it launched $7.4-billion fundraising drive, with the aim of immunizing 300 million people by 2025.