北京鸭法氏囊中B细胞活性因子性质分析

Studies of the B-cell active factors in the bursa of fabricius of Peking Duck

从2～3月龄北京鸭法氏囊得到分子量小于10000道尔顿的提取物。该提取物能显著提高小鼠脾脏空斑形成细胞(简称PFC)的数目。它还具有对抗B细胞抑制剂环磷酰胺(简称CP)的作用:注射了CP的小鼠PFC数目明显下降,此时再注射囊提取物则能恢复小鼠产生PFC的能力;该提取物还能延长致死量CP处理后小鼠的存活期。表明法氏囊提取物中有些因子能够促进B细胞的发育成熟及其功能的正常发挥。把这种因子称为囊素(Bursatin)。经高温或蛋白水解酶处理,囊素的促PFC活性丧失,表明其很可能是肽类物质。囊提取物能提高小鼠脾细胞中cAMP含量,提示囊素可能以cAMP为介导而起作用。此外,囊提取物还有增多胸腺细胞中E-玫瑰花形成细胞数目的活性,表明提取物中可能有多种活性因子或某因子有多种活性。

Bursa of Fabricius is the central organ of B-cell development in birds. There are some active factors in Bursa that are involved in the maturation of B lymphocytes. Bursa extracts from 2-3 month-old peking Duck, with a M. W. of 10,000 dal, can obviously increase the number of plaque-forming cells (PFCs) in normal or cyclophosphamidetreated mouse spleen. Cyclophosphamide (CP) is a kind of B-cell inhibitor. The extracts can also increase the life expectation of mouse treated with deathal dose of CP. These results show that Bursa extracts contain a factor (or some factors) which can promote the development or function of B cells. The factor is named as Bursatin. Because the PFCs-stimulating activity of the factor is susceptible to high temperature and pronase E, Bursatin is infered to be a peptide. The effect of Bursa extracts on elevating the cAMP level of mouse spleen cells suggests that Bursatin may function via cAMP. Besides, it is interesting that we have found that the extracts can also increase the rumber of E-rosett forming cells in pig thymocytes. The result shows that there are several active factors or certain factor poesses different activities in Bursa extracts.