Which ABO phenotype has no antigens but contains both anti-A and anti-B antibodies?

The ABO phenotype that has no antigens but contains both anti-A and anti-B antibodies is O. Individuals with this blood type do not express A or B antigens on the surface of their red blood cells. This absence of antigens is what characterizes the O blood type, making it a universal donor in blood transfusions.

In contrast, the other blood types, A and B, possess specific antigens corresponding to their names. Type A has A antigens and produces anti-B antibodies, while type B has B antigens and produces anti-A antibodies. The AB blood type includes both A and B antigens, meaning it does not produce either anti-A or anti-B antibodies, allowing it to accept any type of blood for transfusions but not making it a universal donor like type O. Thus, type O is unique in having neither antigens nor the potential to react against foreign A or B antigens, which is a critical factor in transfusion compatibility.