In recent years, scientists have identified various naturally occurring mutations in the human genome that ward off Alzheimer’s disease. Now, in a study published July 9 in Molecular Biology and Evolution, researchers explain how one such gene variant initially emerged to protect against a different type of threat: gonorrhea.
According to the paper, a mutant form of an immune receptor, found in roughly one fifth of people, helps the immune system detect Neisseria gonorrhoeae, the bacteria responsible for the sexually transmitted disease. Typically, white blood cells particularly monocytes and macrophages, use a receptor called CD33, to distinguish between host cells and unwelcome pathogens invading the body. When CD33 binds to sialic acids—sugars that tend to adorn the membranes of host cells, acting as a molecular ID— immune cells recognize those cells and prevent the immune system from launching an attack.
But “bacteria are expressing sialic acid as a way to ...
