IDENTIFICATION OF SPECIES DIFFERENCES IN LIPOPROTEIN LIPASE AND MANIPULATION OF FAT DEPOSITION BY MONOCLONAL ANTIBODY FOR THE LIPASE IN CHICKENS

肥胖症（过度脂肪沉积）是人类和动物中常见的代谢紊乱。鸡脂肪组织中的脂蛋白脂酶（LPLase）在决定鸡脂肪沉积方面起主要作用。本研究旨在确定LPL酶在鸡和哺乳动物中的种属差异，并探索通过施用LPL酶的单克隆抗体来控制过量脂肪沉积的可能途径。(1)Triton WR-1339在大鼠中显着抑制LPLase对脂蛋白的水解，但在鸡中抑制程度较小，表明LPLase存在种属差异。(2)甘油被鉴定为稳定LPL酶活性的优良试剂，因为LPL酶对分解敏感。采用羟基磷灰石柱纯化了高比活的鸡和大鼠LOLs。(3)纯化的鸡LPL酶与大鼠的LPL酶在Km、Vm和动力学方面对Triton WR-1339的抑制作用不同。(4)经超滤和Mono Q柱分离纯化，得到了鸡的载脂蛋白C-Ⅱ。在鸡中Apo C-II对LPL酶的激活作用强于大鼠。(5)将纯化的LPLase免疫攻击小鼠以产生杂交瘤，并鉴定了24个对LPLase具有高亲和力的克隆。在24个克隆中，有3个单克隆抗体对LPLase水解脂蛋白具有明显的抑制活性。(6)腹腔注射LPL酶单克隆抗体可抑制鸡脂肪组织LPL酶活性20%，并显著增加血浆甘油三酯浓度，表明单克隆抗体给药可能是一种延缓动物过度脂肪沉积的方法。

Obesity (excessive fat deposition) is a metabolic disorder common in human and animals. Lipoprotein lipase (LPLase) in adipose tissues plays a major role in determining fat deposition in chickens. Present study was undertaken to identify species differences in LPLase in chickens and mammals and to explore the possible ways to manipulate the excess fat deposition by administration of the monoclonal antibodies of LPLase.(1) Hydolysis of lipoproteins by LPLase was markedly inhibited by Triton WR-1339 in rats but inhibited to a small extent in chickens, suggesting existence of species differences in the LPLase.(2) Glycerol was identified for an excellent reagent to stabilize LPLase activity, because LPLase was sensitive to the decomposition. LOLases of chickens and rats were purified with high specific activity by applying hydroxyapatite column.(3) Purified LPLase of chickens differed from that of rats in terms of Km, Vm and kinetics on inhibition by Triton WR-1339.(4) Ultrafiltration and Mono Q columns for apoproteins yielded a purified Apo C-II of chickens. Activation of LPLase by the Apo C-II was potent in chickens more than in rats.(5) Purified LPLase was immunologically challenged to mice to produce the hybridomas and 24 clones characterized with high affinity to LPLase were identified. Three monoclonal antibodies out of 24 clones demonstrated marked inhibitory activity on the lipoprotein hydrolysis by LPLase.(6) Intraperitoneal administration of the monoclonal antibody for LPLase resulted in an inhibition by 20% of adipose tissue LPLase activity and a marked increase in plasma triglyceride concentration in chickens, suggesting that the monoclonal antibody administration may be a possible procedure to retard excessive fat deposition in animals.