Richardson J M, Kaushic C, Wira C R
Department of Physiology, Dartmouth Medical School, Lebanon, New Hampshire 03756-0001, USA.
Biol Reprod. 1995 Sep;53(3):488-98. doi: 10.1095/biolreprod53.3.488.
These studies were conducted to more fully understand the role of uterine epithelial cells (UEC) in immunoglobin (Ig)A movement from tissue into secretions in the female reproductive tract. Indirect immunofluorescence and image analysis showed that the polymeric Ig receptor (pIgR), which is responsible for transporting polymeric IgA (pIgA) across epithelial cells, was expressed in uterine tissues from rats throughout the estrous cycle. UEC pIgR levels were higher at estrus than at either proestrus or diestrus. When UEC were isolated from the uteri of adult rats and grown on cell culture inserts, cells grew to confluence, formed tight junctions, and released secretory component (SC), the external domain of the pIgR, into the apical medium. Irrespective of whether UEC were isolated from the uteri of rats at the diestrous, proestrous, or estrous stages of the reproductive cycle, cells produced SC, indicating that they are capable of IgA transport. 125I-IgA was preferentially transcytosed from the basolateral to the apical surface, demonstrating that dimeric IgA (dIgA) could be transported by UEC in culture. In contrast, the fluid phase marker [3H]inulin moved at a comparable rate in both directions across the cell monolayer. 125I-IgA transport through UEC was saturable and specific for pIgA in that unlabeled pIgA, but not IgG, inhibited 125I-dIgA transcytosis from the basolateral to the apical surface. Immunoprecipitation of 125I-IgA in the apical chamber with rabbit anti-SC antibody indicated that after transepithelial movement, IgA was bound to SC. Northern blot analysis of RNA extracted from UEC demonstrated that cells continued to synthesize pIgR mRNA in culture. Our results suggest that in the uterus, epithelial cells play a key regulatory role in the control of IgA transcytosis from tissue into secretions.
进行这些研究是为了更全面地了解子宫上皮细胞（UEC）在免疫球蛋白（Ig）A从组织进入女性生殖道分泌物过程中的作用。间接免疫荧光和图像分析表明，负责将聚合IgA（pIgA）转运穿过上皮细胞的聚合Ig受体（pIgR）在大鼠整个发情周期的子宫组织中均有表达。发情期UEC的pIgR水平高于发情前期或间情期。当从成年大鼠子宫中分离出UEC并在细胞培养插入物上培养时，细胞生长至汇合，形成紧密连接，并将分泌成分（SC），即pIgR的胞外结构域，释放到顶端培养基中。无论UEC是从生殖周期的间情期、发情前期还是发情期大鼠的子宫中分离出来的，细胞都能产生SC，这表明它们能够进行IgA转运。125I-IgA优先从基底外侧向顶端表面进行跨细胞转运，表明二聚体IgA（dIgA）可被培养中的UEC转运。相比之下，液相标记物[3H]菊粉在细胞单层的两个方向上以相当的速率移动。125I-IgA通过UEC的转运是可饱和的，且对pIgA具有特异性，因为未标记的pIgA而非IgG可抑制125I-dIgA从基底外侧向顶端表面的跨细胞转运。用兔抗SC抗体对顶端腔室中的125I-IgA进行免疫沉淀表明，经上皮移动后，IgA与SC结合。对从UEC中提取的RNA进行Northern印迹分析表明，细胞在培养中继续合成pIgR mRNA。我们的结果表明，在子宫中，上皮细胞在控制IgA从组织向分泌物的跨细胞转运中起关键调节作用。
