Fifty years ago this September, Robert Gallo and his colleagues published a paper describing what became known as interleukin-2 (IL-2), a protein essential for the growth and regulation of T cells. In an opinion piece marking the anniversary, Gallo reflects on how that basic finding reshaped medicine in ways the team could not have predicted.
IL-2 made it possible to grow human T cells in the lab, which in turn led to the discovery of the first human retroviruses, including HTLV-1 and HTLV-2, and eventually to the identification of HIV as the cause of AIDS and the development of a blood test to protect the blood supply. Gallo notes that many immunology colleagues would instead point to IL-2's role in launching modern cancer immunotherapy, through work by Steven Rosenberg, and in advancing understanding of T-cell memory, through Rafi Ahmed. The source, a single opinion piece, does not include contrasting views, but Gallo acknowledges that the 'greatest legacy' depends on whom you ask.
Gallo's larger argument is about the nature of scientific discovery. The team was originally hunting for growth factors, not treatments for cancer or AIDS. He warns that calls to fund only research with immediate applications are misguided, because the most consequential discoveries often come from questions whose impact cannot be foreseen. The article is an opinion essay, so it presents Gallo's perspective without opposing commentary.