Immune agglutinin -->
1. An antibody that causes clumping or agglutination of the bacteria or other cells which either stimulated the formation of the agglutinin, or contain immunologically similar, reactive antigen.
Synonym: agglutinating antibody, immune agglutinin.
2. A substance, other than a specific agglutinating antibody, that causes organic particles to agglutinate, commonly qualified, e.g., plant agglutinin.