Natural killer cells

Published on February 28, 2021   24 min

Other Talks in the Series: The Immune System - key concepts and questions

Hello, I'm Dr. Pippa Kennedy of the Masonic Cancer Research Center in the University of Minnesota. This lecture focuses on natural killer cells (or NK cells) which are, in my heavily biased opinion, the most interesting cells of the human immune system. I'm currently researching how natural killer cells can be put to work eliminating human cancer cells, as part of the revolution in cancer immunotherapy. I'm doing this work at the Masonic Cancer Research Center in Minnesota. I've also investigated the protein interactions that cause an NK cell to kill diseased cells within the body. Before that, I was studying how natural killer cells in the uterus are, somewhat unexpectedly, a crucial component of a healthy pregnancy. But before we talk about any of these fascinating aspects of NK cell biology, let's start back in 1975 when natural killer cells were first discovered.
The state of the field in 1975 was that the immune system had two broad strategies for destroying pathogens or diseased cells within the body. Firstly, humoral immunity consisted of proteins such as antibodies or complement that could immobilize pathogens and disrupt their membranes. Secondly, cellular cytotoxicity relied on immune cells to kill pathogens. The different types of cellular cytotoxicity, phagocytosis, antibody-dependent cellular cytotoxicity (or ADCC), and T-cell cytotoxicity, each have features that make them unique. Macrophages phagocytose (or 'gobble up') diseased cells, antibodies are required for ADCC, and T-cells produce slow-starting, long-lasting memory responses. This overview of immunity holds true today, but something is missing.