Salik E, Tyorkin M, Mohan S, George I, Becker K, Oei E, Kalb T, Sperber K
Divisions of Clinical Immunology and Pulmonary and Critical Care Medicine, Mount Sinai Medical Center, New York City, New York, USA.
Am J Respir Cell Mol Biol. 1999 Sep;21(3):365-79. doi: 10.1165/ajrcmb.21.3.3529.
We investigated accessory cell function, antigen (Ag) trafficking, and uptake of immune complexes in isolated nasal epithelial cells (NEC) and airway epithelial cells (AEC), as well as in the two respiratory epithelial cell lines A549 and BEAS-2B. The NEC and AEC were capable of supporting Ag-specific as well as phytohemagglutinin-induced and anti-CD3 antibody-induced T-cell proliferation. We colocalized fluorescein isothiocyanate (FITC)-labeled Ags with human leukocyte antigen (HLA)-DR in A549 and BEAS-2B, utilizing laser confocal microscopy. Respiratory epithelial cells stimulated and unstimulated with interferon (IFN)-gamma were pulsed with FITC-labeled Ags for varying periods and evaluated for their ability to internalize Ag. In the unstimulated cells, intracellular punctate staining was evident at 60 min and persisted up to 120 min. In the IFN-gamma-stimulated cells (100 U/ml for 48 h), uptake occurred at 30 min, was maximal at 60 min, and diminished at 120 min. We conducted kinetic studies in the A549 and BEAS-2B cells, utilizing electron microscopy with colloidal gold-conjugated Ags (Au-OVA). At 15 min, Au-OVA was evident in the early compartments resembling the compartment of uncoupling of receptor and ligand. At 30 min, multivesicular bodies were labeled with Au-OVA, and by 60 min Au-OVA was present in the primary and secondary lysosomes. The FITC-labeled Ags colocalized with an early endosomal marker (anti-cathepsin D), a late endosomal marker (M6PR), a lysosomal marker (CD63), and with 3-(2, 4-dinitroanilino)-3'-aminomethyldipropylamine, a marker of acidic vesicles. The BEAS-2B and A549 cells, and NEC and AEC, expressed surface Fcgamma receptor and internalized IgG immune complexes. The NEC and AEC also expressed the costimulatory molecules CD80 and CD86 as determined with flow cytometry, the reverse transcription-polymerase chain reaction for RNA, and immunohistochemistry, and T-cell proliferation could be blocked by treating NEC and AEC with anti-CD80 and anti-CD86 antibodies. Our findings suggest that respiratory epithelial cells may have a role in local Ag presentation.
我们研究了分离的鼻上皮细胞（NEC）和气道上皮细胞（AEC）以及两种呼吸道上皮细胞系A549和BEAS-2B中的辅助细胞功能、抗原（Ag）转运和免疫复合物摄取。NEC和AEC能够支持抗原特异性以及植物血凝素诱导和抗CD3抗体诱导的T细胞增殖。我们利用激光共聚焦显微镜，将异硫氰酸荧光素（FITC）标记的抗原与人白细胞抗原（HLA）-DR在A54 和BEAS-2B细胞中进行共定位。用FITC标记的抗原对用干扰素（IFN）-γ刺激和未刺激的呼吸道上皮细胞进行不同时间段的脉冲处理，并评估它们内化抗原的能力。在未刺激的细胞中，60分钟时可见细胞内点状染色，并持续至120分钟。在用IFN-γ刺激的细胞（100 U/ml，处理48小时）中，30分钟时开始摄取，60分钟时达到最大，120分钟时减少。我们在A549和BEAS-2B细胞中进行了动力学研究，采用胶体金偶联抗原（Au-OVA）的电子显微镜技术。15分钟时，Au-OVA出现在类似于受体与配体解偶联区室的早期区室中。30分钟时，多泡体被Au-OVA标记，到60分钟时，Au-OVA存在于初级和次级溶酶体中。FITC标记的抗原与早期内体标记物（抗组织蛋白酶D）、晚期内体标记物（M6PR）、溶酶体标记物（CD63）以及酸性囊泡标记物3-（2,4-二硝基苯胺）-3'-氨基甲基二丙胺共定位。BEAS-2B和A549细胞以及NEC和AEC表达表面Fcγ受体并内化IgG免疫复合物。通过流式细胞术、RNA的逆转录-聚合酶链反应和免疫组织化学测定，NEC和AEC也表达共刺激分子CD80和CD86，并且用抗CD80和抗CD86抗体处理NEC和AEC可阻断T细胞增殖。我们的研究结果表明呼吸道上皮细胞可能在局部抗原呈递中发挥作用。
