B Cells

Tag makers

B cells are a kind of white blood cell. They are made in your bone marrow, the soft middle of your bones.

A B cell is round, with a big nucleus that fills most of the cell. It's covered in Y-shaped tags called antibodies.

Sticky tags that grab germs

Each kind of antibody fits one kind of germ, a bit like a key fits one lock.

• 1. A B cell finds a germ that fits its antibodies.
• 2. It makes lots of copies of itself.
• 3. Many copies become antibody factories that send out thousands of antibodies every second.
• 4. The antibodies stick to the germs. This stops some germs from getting into cells, and makes it easy for macrophages to find and eat them.

B cells with a memory

After a germ is beaten, some B cells stay around as memory B cells. They can remember that germ for years.

If the same germ comes back, they make antibodies very fast. Often you fight it off before you even feel sick.

B cell quiz