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Immune System Master Class

Grandmother and granddaughter hug through a plastic drop cloth.

Grandmother and granddaughter hug through a plastic drop cloth in Wantagh, N.Y., in May 2020. It was their first physical contact in months.

Al Bello/Getty Images

In early 2020, when SARS-CoV-2 spread around the globe, national, regional and local politicians and health authorities held daily press conferences to explain the importance of R0 (a mathematical indicator of a disease’s contagiousness pronounced “R naught”); media pundits debated the precise definition of “herd immunity”; and social media ads for face coverings promoted the concept of “viral load.” Never, perhaps, had the general public learned so much so quickly about the human immune system.

Since COVID’s discovery, scientists have raced to determine how it undermines the body’s natural defenses to wreak havoc on the lungs and other organs. Thankfully, vaccines using a new mechanism of action based on decades of immune research were developed in under a year and proved to be powerful protection against the virus. Because of its impressive success, mRNA vaccine technology is already being tested against a host of other afflictions from malaria to tuberculosis.

Researchers are making other immunological strides against many infectious diseases as well. Impressive advances have been reported against HIV, including new ways to weaken the virus. A vaccine based on a group of viruses typically excreted in feces might prevent type 1 diabetes. And a controversial line of research posits the intriguing possibility that a vaccination for one disease may provide protection against others.

Harnessing a person’s own immune system to fight disease is revolutionizing cancer therapy. The past decade has seen remarkable progress in manipulating key immune players such as CAR T cells and checkpoint inhibitors to treat nonsolid cancers. Promising new trials are training this therapy against solid tumors and pairing it with individual patient protein analysis to increase the chances that treatments will work.

A nagging mystery of the human immune system is why it sometimes turns on people’s own, otherwise healthy bodies. Women account for nearly 80 percent of cases of autoimmune disorders, potentially implicating reproductive hormones, X chromosomes and gut microbiota. An answer to this conundrum most likely doesn’t exist in one discrete line of inquiry. Instead it will require enormous data sets, drawn from genetic studies to microbiome assessments to environmental surveys.

Once thought to be independent immunological operators, the brain and the immune system now appear to work in close conjunction, protecting each other through intricate communication and keeping a log of previous pathological invaders. Sickness or health does depend on how well we eat, sleep and move, adding more urgency for the need to ensure all humans have access to quality nutrition and safe communities.

The coronavirus pandemic gave unprecedented urgency to immune research, revealing both the extraordinary defense system our bodies evolved to survive and the ferocity of viruses, bacteria and environmental stressors that threaten us. In a time plagued by not only a deadly pathogen but also misinformation and uncertainty, the science of the immune system has never been more sought after or necessary.

Andrea Gawrylewski is chief newsletter editor at Scientific American. She writes the daily Today in Science newsletter and oversees all other newsletters at the magazine. In addition, she manages all special collector's editions and in the past was the editor for Scientific American Mind, Scientific American Space & Physics and Scientific American Health & Medicine. Gawrylewski got her start in journalism at the Scientist magazine, where she was a features writer and editor for "hot" research papers in the life sciences. She spent more than six years in educational publishing, editing books for higher education in biology, environmental science and nutrition. She holds a master's degree in earth science and a master's degree in journalism, both from Columbia University, home of the Pulitzer Prize.

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SA Special Editions Vol 31 Issue 2sThis article was originally published with the title “Immune System Master Class” in SA Special Editions Vol. 31 No. 2s (), p. 1
doi:10.1038/scientificamericanimmunesystem0322-1