In the ABO blood group system, which antigen is present in blood type B?

In the ABO blood group system, individuals with blood type B possess the B antigen on the surface of their red blood cells. The presence of the B antigen distinguishes this blood type from others in the ABO system. Blood type B means that the person's immune system recognizes the B antigen as self, while it would recognize the A antigen (present in blood type A) as foreign.

When blood type B is transfused into a person with type A or AB blood, the immune response could activate because of the incompatible A antigen. Therefore, understanding blood types is crucial for safe blood transfusions and compatibility. In summary, blood type B is characterized specifically by the presence of the B antigen.