My Discovery of the Natural Killer Cell
By Jerry T. Thornthwaite, Ph.D.
In 1972, I presented a poster session with my major Professor, Dr. Bob Leif, at the annual Reticuloendothelial Society Meeting. On my poster, I presented on very unusual cells from the spleen (and later from the lymph nodes) of non-immunized mice that destroyed sheep red blood cells (SRBC) on contact. I came very close to publishing the article in Science which took some time and effort, but the conclusion was that it was more suitable for the immunology journals. The papers were accepted in the Journal of Immunology. I did not know the proper name for these cells but was able to develop a way of enumerating them, determine their density and enrichment in linear bovine serum albumin gradients and study their morphology utilizing light, scanning electron and transmission electron microscopy. Many years later, I developed a clinical application by in vitro enriching natural killer cells for infusion into patients. Currently, I am investigating natural substances that are supposed to increase the natural killer cell response. Unlike complement mediated IgM antibody destruction of SRBC, which showed lyses of "plaques" of SRBC appearing as deflated balloons (Fig. 1), the complete destruction of the SRBC did not require prior immunization with SRBC or complement (Fig. 2). Thus, I gave them the name "complement independent plaque-forming cells" (CIPFC) or "rough lymphocyte plaque-forming cells" when I was able to perform scanning electron microscopy (SEM). Later, Heberman (1973) and Oldham (1973) used the term "Natural Killer Cell".