Live Science
By
May 12, 2022
While working to map every cell in the human body, scientists uncovered an elusive type of immune cell that first emerges in the womb. The existence of such cells in humans has been hotly debated — until now.
These mysterious cells, known as B-1 cells, were first discovered in mice in the 1980s, according to a 2018 review in The Journal of Immunology. These cells arise early in mouse development, in the womb, and they produce various antibodies when activated. Some of these antibodies latch onto the mouse’s own cells and help to clear dying and dead cells from the body. Activated B-1 cells also make antibodies that act as a first line of defense against pathogens, like viruses and bacteria.