Definition

A type of substance found in the body that can trigger an immune response in individuals who do not have it, often seen in different blood types within the same species.

Example

The alloantigen in the blood transfusion was recognized by the recipient's immune system, leading to a reaction.

Conversation

I was reading about blood types and came across the term alloantigen.

Oh really? What does that mean exactly?

It refers to an antigen that some people have, but others in the same species don’t.

That’s interesting! I had no idea our blood could be so complex.

Synonyms & Antonyms

Root Explanation

Alloantigen → It is formed from "allo-" (from Greek "allos", meaning other or different) and "antigen" (from Greek "anti-" meaning against and "genes" meaning produced by or born of). The word refers to an antigen that is present in one individual but not in another of the same species, thus being recognized as foreign or different.

Memory Tip

Think of 'allo-' meaning 'other' and 'antigen' as something that is 'produced against' — this helps you remember that an alloantigen is something that is recognized as foreign by the immune system because it is different from the individual's own antigens.

Visually Confused Words