Willermain F, Caspers-Velu L, Baudson N, Dubois C, Hamdane M, Willems F, Velu T, Bruyns C
I.R.I.B.H.N., Campus Erasme, Université Libre de Bruxelles, Faculty of Medicine, Brussels, Belgium.
Invest Ophthalmol Vis Sci. 2000 Oct;41(11):3485-91.
To examine the CD40 costimulatory molecule expression on normal resting or activated adult human retinal pigment epithelium (hRPE) cells and to evaluate its role as an activation molecule considering the potential antigen presentation functions of hRPE cells.
Expression of HLA-DR and costimulatory (CD40, B7.1, B7.2, CD54, and CD58) molecules on hRPE cells was analyzed by flow cytometry. CD40 triggering was performed using soluble CD40L or cocultures with CD40L transfected fibroblasts. Interleukin (IL)-6, -8, -10, and -12 secretions were measured by enzyme-linked immunosorbent assay. Antigen presentation function of hRPE cells was assessed by coculturing hRPE cells with allogeneic T cells. T-cell proliferation was measured by [(3)H]-thymidine incorporation, and T-cell apoptosis by measurement of caspase-3 activity.
Interferon (IFN)gamma-activated hRPE cells expressed CD40, but not B7.1 or B7.2. Although interferongamma enhanced IL-6 and IL-8 production, CD40 triggering of IFNgamma-activated hRPE cells did not induce IL-12 secretion. hRPE cells did not stimulate allogeneic resting T cells and downregulated phytohemagglutinin-activated allogeneic T cells via a cell-to-cell contact-dependent mechanism. Some induction of apoptosis was detected.
CD40 is expressed on IFNgamma-activated hRPE cells. Its ligation leads to an increased production of IL-6 and IL-8 but fails to induce B7.1 or B7. 2 expression, or to induce IL-12 secretion. Accordingly, hRPE cells do not activate allogenic T cells but inhibit T-cell proliferation, partly through induction of apoptosis. These results suggest that hRPE cells could be implicated more in a deviant antigen presentation. If the exact molecular mechanisms are unclear, it is likely that CD40-CD40L interaction could play a role in this process.
检测正常静息或活化的成人人类视网膜色素上皮（hRPE）细胞上共刺激分子CD40的表达，并鉴于hRPE细胞潜在的抗原呈递功能，评估其作为活化分子的作用。
采用流式细胞术分析hRPE细胞上HLA-DR和共刺激分子（CD40、B7.1、B7.2、CD54和CD58）的表达。使用可溶性CD40L或与转染了CD40L的成纤维细胞共培养进行CD40触发。通过酶联免疫吸附测定法检测白细胞介素（IL）-6、-8、-10和-12的分泌。通过将hRPE细胞与同种异体T细胞共培养来评估hRPE细胞的抗原呈递功能。通过[³H]胸苷掺入法测量T细胞增殖，通过测量半胱天冬酶-3活性检测T细胞凋亡。
干扰素（IFN）γ活化的hRPE细胞表达CD40，但不表达B7.1或B7.2。虽然干扰素γ增强了IL-6和IL-8的产生，但CD40触发干扰素γ活化的hRPE细胞并未诱导IL-12分泌。hRPE细胞不刺激同种异体静息T细胞，并通过细胞间接触依赖性机制下调植物血凝素活化的同种异体T细胞。检测到一些凋亡诱导现象。
CD40在干扰素γ活化的hRPE细胞上表达。其连接导致IL-6和IL-8产生增加，但未能诱导B7.1或B7.2表达，也未诱导IL-12分泌。因此，hRPE细胞不激活同种异体T细胞，但抑制T细胞增殖，部分是通过诱导凋亡。这些结果表明，hRPE细胞可能更多地参与异常抗原呈递。如果确切的分子机制尚不清楚，CD40-CD40L相互作用很可能在此过程中发挥作用。
