And we'll see exactly what that means in just a moment. So this is our red blood cell of a person that has blood type A. So blood type A individual contains red blood cells that contain a membrane protein we call antigen A. And so that individual will not produce antigen, antigen A antibodies. They will only produce antigen B antibodies because they do not have any antigen B proteins on the membrane. On the other hand, let's focus on the blood type B.