Question

People with ABO blood type \(\mathrm{O}\) ___________. a. have both antigens \(A\) and \(B\) on their erythrocytes b. lack both antigens \(A\) and \(B\) on their erythrocytes c. have neither anti- A nor anti- B antibodies circulating in their blood plasma d. are considered universal recipients

Short answer

Answer: People with ABO blood type O lack both antigens A and B on their erythrocytes.

Step-by-step solution

Understand the ABO blood type system

The ABO blood type system classifies blood into four main types based on the presence or absence of antigens A and B on the surface of red blood cells (erythrocytes). These blood types are A, B, AB, and O. The blood type also determines the presence of specific antibodies in the blood plasma.

Recognize the blood type O characteristics

In the case of blood type O, people do not have A and B antigens on the surface of their erythrocytes. However, they have both anti-A and anti-B antibodies in their blood plasma.

Match the correct statement

Based on the information about blood type O, we can match the correct statement from the given options: a. have both antigens A and B on their erythrocytes - This statement is incorrect. b. lack both antigens A and B on their erythrocytes - This statement is correct. c. have neither anti-A nor anti-B antibodies circulating in their blood plasma - This statement is incorrect. d. are considered universal recipients - This statement is incorrect, as people with blood type O are considered universal donors, not recipients. The correct statement related to people with ABO blood type O is: b. lack both antigens A and B on their erythrocytes

Key concepts

Antigens on Erythrocytes

In the world of blood transfusions and typing, understanding the presence of certain proteins on the surface of red blood cells, known as antigens, is crucial. These antigens are essential for determining blood type and compatibility. In the ABO blood type system, there are two main antigens referred to as A and B.

Individuals with type A blood have the A antigen on their erythrocytes, those with type B blood have the B antigen, and type AB blood has both. However, those with type O blood, like the example from the textbook exercise, lack both antigens A and B on their erythrocytes. This absence of antigens makes O type blood unique and has implications for blood transfusions since these individuals can donate blood to any of the other ABO blood types without the risk of their erythrocytes being attacked by the recipient's immune system.

Blood Plasma Antibodies

Blood plasma antibodies are just as important as antigens in determining blood transfusion compatibility. Antibodies are the immune system's defenders, recognizing and attacking cells that display antigens different from those found in the host's own body.

In the context of the ABO blood type system, for each antigen that is not present on a person's erythrocytes, there's typically a corresponding antibody in their plasma. Hence, type A blood contains anti-B antibodies, type B blood contains anti-A antibodies, and AB blood contains neither anti-A nor anti-B antibodies, since their erythrocytes carry both A and B antigens. Type O blood, as mentioned earlier, lacks A or B antigens, and consequently, their plasma contains both anti-A and anti-B antibodies. These antibodies can rapidly identify and attack transfused erythrocytes with mismatched antigens, making the knowledge of someone’s blood type critical to safe transfusions.

Universal Blood Donors

The term 'universal donor' is integral to the puzzle of blood transfusions. It refers to individuals with a specific ABO blood type whose erythrocytes can be transfused to any other ABO blood type recipients without serious risk of an immune reaction. This universally compatible blood type is O negative.

As learned from the exercise, individuals with blood type O have no A or B antigens on their erythrocytes, which prevents the activation of the recipient’s immune system's antibodies. Therefore, when a recipient with a different ABO blood type receives type O blood, their antibodies find no antigens to attack. This phenomenon makes type O negative donors especially valuable and their blood a critical resource for emergency transfusions, where there’s no time to type and crossmatch the recipient's blood.