Expression of invariant chain (CD 74) and major histocompatibility complex (MHC) class II antigens in the human fetus
Expression of invariant chain (CD 74) and major histocompatibility complex (MHC) class II antigens in the human fetus
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DOI：
10.1177/002215540205000404
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发表时间：
2002-04-01
影响因子：
3.2
通讯作者：
Lögdberg, L
中科院分区：
文献类型：
--
作者：
Badve, S;Deshpande, C;Lögdberg, L
在免疫应答的起始期间，抗原呈递细胞利用MHC II类抗原作为关键分子将小肽呈递给CD 4阳性淋巴细胞。不变链（li; CD 74）通过影响MHC II类分子的表达和肽加载在该过程中起关键作用。因此，这些分子的协调表达被认为在抗原呈递中起重要作用。本研究探讨了这些分子在胎儿组织中的表达。分别使用市售的li/CD 74（LN 2）和MHC II类抗原（LN 3）的单克隆抗体对来自流产胎儿（年龄范围7-22周）的福尔马林固定、石蜡包埋的多器官组织块进行li/CD 74和MHC II类抗原的免疫染色。在皮肤、近端肾小管、小肠粘膜尖端和网状内皮系统细胞（包括脾脏和胸腺）中观察到li/CD 74和MHC II类抗原的协同染色。li/CD 74的表达，但不是MHC II类抗原，被认为是在肺泡上皮细胞在所有情况下，在睾丸间质细胞（11/11检查睾丸）。染色的分布和强度没有随年龄的变化显着。总之，本研究描述了li/CD 74和MHC II类抗原在人胎儿组织中的分布。协调表达的li/CD 74和MHC II类抗原被确定在大多数胎儿组织，但也有显着的例外。在所有情况下，这采取在不存在MHC II类表达的情况下表达li/CD 74的形式。在肺泡上皮细胞和睾丸间质细胞中的不一致性尤其显著。这表明li/CD 74分子除了其在抗原呈递中的作用之外还具有功能作用。
During the initiation of an immune response, antigen-presenting cells employ MHC class II antigens as key molecules to present small peptides to CD4-positive lymphocytes. The invariant chain (li; CD74) plays a critical role in this process by influencing the expression and peptide loading of the MHC class II molecules. Therefore, coordinate expression of these molecules is believed to play an important role in antigen presentation. This study explores the expression of these molecules in fetal tissues. Formalin-fixed, paraffin-embedded multi-organ tissue blocks from aborted fetuses (age range 7-22 weeks) were immunostained for li/CD74 and MHC class II antigens using commercially available monoclonal antibodies for li/CD74 (LN2) and MHC class II antigens (LN3), respectively. Coordinate staining for li/CD74 and MHC class II antigens was seen in the skin, proximal renal tubules, tips of small intestinal mucosa, and cells of the reticuloendothelial system, including the spleen and thymus. Expression of li/CD74, but not of MHC class II antigens, was seen in pulmonary alveolar epithelium in all cases and in testicular Leydig cells (11 of 11 testes examined). The distribution and intensity of staining did not change significantly with age. In conclusion, this study describes distribution of li/CD74 and MHC class II antigens in human fetal tissues. Coordinate expression of li/CD74 and MHC class II antigens was identified in most fetal tissues, but there were also notable exceptions. In all cases this took the form of expression of li/CD74 in the absence of MHC class II expression. Discordance was particularly striking in pulmonary alveolar epithelium and testicular Leydig cells. This suggests that the li/CD74 molecule has functional roles in addition to its role in antigen presentation.