The Invisible Kingdom: Reimagining Chronic Illness

by Meghan O'Rourke

With my instructors’ tutelage, I came to see the immune system as a kind of college where so-called naïve immune cells grow up and—as if choosing a major—are trained to focus on a specific foreign substance. When our adaptive immune cells meet their first antigen, or bit of foreign matter, they go through structural and chemical changes. Imprinted by that antigen—as if via a kiss, Caleb said, drawing a picture of an antigen and antibody interlocked—the naïve immune cell becomes an enemy specific to it. (This is the premise behind most vaccines: they contain an altered version of a virus, to make the body produce antibodies designed specifically to lock into it.) T cells known as “T-helper cells” (technically, CD4+ T-helper lymphocytes) help ramp up the immune response in the body, stimulating B cells to produce antibodies and stimulating T killer cells, which can kill cells infected by virus. Autoimmunity and allergies occur when immune cells mistakenly identify as pathogens things that are not threats (the thyroid, the liver, pollen, cat dander) and an immune response ensues, possibly because of what is known as “molecular mimicry.” Your immune system, in trying to attack a pathogenic Epstein-Barr virus protein, ends up attacking similar-looking molecules in the body.