Abstract: purification of IgG from serum of giant panda was carried out and rabbit antisera to the IgG was prepared．The reactions between the antisera and sera from black bear(Salenarctes thibetanus)，lesser panda(Ailurus fulgens) dog，cat,sheep，guinea pig，rabbit and human were detected by immunodiffusion and micloim -munoelectrophoresis．The results showed that the sera from carnivoie including black bear，lesser
panda，dog，cat，produced definitely precipitation line with the antisera， but those of sheep，guinea pig，rabbit and human did not react with the antisera at al1．The precipita
tion line of black bear sera with the antisera was fused with those of giant pandaIgG or seta． It showed that taxonomic position of giant panda is closer to that of black bear．We think that giant panda might be close to black bear，but not to lesser panda．

Key words: Ailuropoda melanoleuca, immunoglobulin, IgG, Taxonomy

摘要： 从大熊猫血清中纯化出免疫球蛋白(IgG)，以此作为抗原免疫家兔，获得兔抗大熊猫IgG血清。以黑熊、小熊猫、狗、猫等动物血清为抗原，兔抗大熊猫IgG 血清为抗体．进行了免疫扩散和微量免疫电泳实验。
实验结果表明，收集的食肉目动物：黑熊、小熊猫、狗、猫的血清都可与兔抗大熊猫GIg血清进行沉淀反应，其中尤以黑熊的反应最强且与大熊猫的反应沉淀线完全融合；小熊猫、狗、猫反应较弱且融入大熊猫反应沉淀线后形成树板状。从此看出大熊猫lgG 与黑熊的IgG最相似，从亲缘关系上讲，二者更为接近，大熊猫反应属熊科。

关键词: 大熊猫, 免疫球蛋白, 分类学