ag·glu·ti·nate / əˈgloōtnˌāt/ • v. firmly stick or be stuck together to form a mass. ∎  Biol. (with reference to bacteria or red blood cells) clump together: [tr.] these strains agglutinate human red cells| [intr.] cell fragments agglutinate and form intricate meshes. ∎  [tr.] Linguistics combine (simple words or parts of words) without change of form to express compound ideas.DERIVATIVES: ag·glu·ti·na·tion / əˌgloōtnˈāshən/ n.

agglutination The clumping together by antibodies of microscopic foreign particles, such as red blood cells or bacteria, so that they form a visible pellet-like precipitate. Agglutination is a specific reaction, i.e. a particular antigen will only clump in the presence of its specific antibody; it therefore provides a means of identifying unknown bacteria and determining blood group. When blood of incompatible blood groups (e.g. group A and group B – see ABO system) is mixed together agglutination of the red cells occurs (haemagglutination). This is due to the reaction between antibodies in the plasma (agglutinins) and agglutinogens (antigens) on the surface of the red cells.

agglutination The clumping of cells that is caused by the reaction between antigens on their surfaces and antibodies in their external environment. See RHESUS FACTOR.

agglutination Clumping of bacteria or erythrocytes by antibodies that react with antigens on the cell surface.

agglutination (clumping) (ă-gloo-tin-ay-shŏn) n. the sticking together of such microscopic antigenic particles as red blood cells or bacteria so that they form visible clumps.
—agglutinative adj.