agglutinin
Technical term in immunology and biology for an antibody or substance that causes agglutination of cells or particles.
凝集素は、血液型判定に用いられる。
Agglutinins are used in blood typing.
Compound of 凝集 (gyōshū, 'agglutination') and 素 (so, 'element' or 'factor'), likely a calque from German or English scientific terminology.