頂體

　　dongwujingzidedingtishiyougaoerjiqixingchengdeshuangcengmodexibaoqi，weigaiyujingzitoubuxibaoheqianfangdemaoxingjiegou，weiyujingziheyuzhimozhijian。dingtineideluanjiehedanbai（結合素）可識別特異糖基序列，具有種的特異性。頂體內含有多種水解酶，類似於溶酶體酶或胰酶樣蛋白酶。