IMMUNOLOGICAL AND MOLECULAR STUDIES ON SECRETORY IGA

本研究得到国家教育科学文化部科学研究资助项目(A)的支持，研究结果总结如下：1。人胎儿连接(J)链、分泌成分（SC）、IgA和IgM的发育和定位(1)妊娠第6周发现J链表达有显著反应性，7周时发现mu链的表达落后于早期胎儿肝脏J链的表达。(2)孕16周时，小鼠脾脏、胸腺、小肠和肺部均检测到J链和mu链。(3)妊娠16周后各脏器均未检出SC和α链。细胞因子和SC在大肠上皮细胞株HT-29中的表达(1)沙门菌LPS刺激HT-29可导致IL-6、IL-8、tgf - β 1和SC mRNA的表达。(2) ifn - γ、tnf - α、il -1 α、il -1 β、IL-4或IL-6刺激HT-29后，SC mRNA和SC蛋白表达上调。(3)提示HT-29中存在I型IL-1受体。(1)不产生免疫球蛋白的无脊椎动物具有与脊椎动物相似的J链mRNA。(2)蚯蚓（Eisenia faetida） J链cDNA和氨基酸序列与人类和小鼠具有高度同源性（分别为75%、76%）。(3)蚯蚓和鼻涕虫的J链蛋白定位于皮肤和小肠上皮细胞。(4)这些结果表明，J链的真正功能可能不是聚合免疫球蛋白。

The results obtained by this study supported by The Ministry of Education, Science and Culture, Grant-in-Aid for Scientific Research (A) were summarized below ;1 .Development and localization of Joining (J) chain, secretory component (SC), IgA and IgM in human fetus(1) a significant reactivity of J chain expression was found at the 6 th gestational week and the expression of mu chain at week 7 laged behind that of J chain in the early fetal liver.(2) both J chain and mu chain were detected at the 16 th gestational week in spleen, thymus, small intestine and lung.(3) SC and alpha chain could not detect until the 16 th gestational week in all organs examined.2. Expression of cytokine and SC in colonic epithelial cell line HT-29(1) HT-29 stimulated with Salmonella minesota LPS resulted in the expression of IL-6, IL-8, TGF-beta1 and SC mRNA.(2) up-regulation of SC mRNA and protein was detected in HT-29 stimulated with IFN-gamma, TNF-alpha, IL-1alpha, IL-1beta, IL-4 or IL-6.(3) presence of IL-1 receptor type I in HT-29 was suggested.3. Phylogeny of J chain(1) invertebrates that do not produce immunoglobulins have the J chain mRNA similar to vertebrates.(2) earthworm (Eisenia faetida) J chain cDNA as well as amino acid sequence has a high degree of homnology (75%, 76%) to human and mouse, respectively.(3) J chain protein in earthworm and slug was localized in the epithelial cells of skin and small intestine.(4) these results suggested that the real function of J chain may not be a polymerization of immunoglobulin.