Gao J X, Issekutz A C
Departments of Pediatrics and Microbiology and Immunology, Dalhousie University, Halifax, NS, Canada.
Immunology. 1996 Nov;89(3):375-83. doi: 10.1046/j.1365-2567.1996.d01-750.x.
In chronic inflammatory conditions, mononuclear cells infiltrate the involved connective tissue and may persist, perhaps because of binding to adhesion molecules on connective tissue cells, as well as extracellular matrix. Here we investigated whether vascular cell adhesion molecule-1 (VCAM-1) may be induced on human dermal fibroblasts by proinflammatory cytokines. Expression of VCAM-1 was determined by Northern blotting, cell enzyme-linked immunosorbent assay (ELISA) and flow cytometry. Only trace amounts of VCAM-1 mRNA or protein were constitutively expressed on dermal fibroblasts but both were rapidly (within 4 hr) upregulated by tumour necrosis factor-alpha (TNF-alpha) and interleukin-1 alpha (IL-1 alpha) and somewhat slower (20 hr) by interferon-gamma (IFN-gamma). The combination of TNF-alpha and IFN-gamma had at least an additive effect. The adhesion function of the expressed VCAM-1 was examined by studying the adhesion of the Jurkat T lymphocytes to fibroblasts. Adhesion of Jurkat cells to dermal fibroblasts was markedly increased by stimulation of fibroblasts with TNF-alpha and IFN-gamma (22% of cells adhered versus 9% on unstimulated fibroblasts). The increased adhesion was inhibited to that on unstimulated fibroblasts by monoclonal antibody (mAb) to domain 1 of VCAM-1, but not by mAb to domain 4. MAb to very late antigen-4 (VLA-4), the integrin counter-receptor on lymphocytes for VCAM-1, completely inhibited the increase in Jurkat cell adhesion to activated fibroblasts and partly also inhibited basal adhesion to unstimulated fibroblasts. These results suggest that VCAM-1 expression by dermal fibroblasts is inducible at the mRNA, protein and functional levels by proinflammatory cytokines. The VLA-4/VCAM-1 pathway maybe involved in adhesive interactions between T lymphocytes and activated fibroblasts in the skin during chronic dermal inflammatory conditions.
在慢性炎症状态下，单核细胞浸润受累的结缔组织并可能持续存在，这可能是由于其与结缔组织细胞以及细胞外基质上的黏附分子结合所致。在此，我们研究了促炎细胞因子是否可诱导人皮肤成纤维细胞表达血管细胞黏附分子-1（VCAM-1）。通过Northern印迹法、细胞酶联免疫吸附测定（ELISA）和流式细胞术来测定VCAM-1的表达。皮肤成纤维细胞仅组成性表达微量的VCAM-1 mRNA或蛋白，但二者均可被肿瘤坏死因子-α（TNF-α）和白细胞介素-1α（IL-1α）迅速（4小时内）上调，而被干扰素-γ（IFN-γ）上调的速度稍慢（20小时）。TNF-α和IFN-γ联合使用至少具有相加作用。通过研究Jurkat T淋巴细胞与成纤维细胞的黏附来检测所表达的VCAM-1的黏附功能。用TNF-α和IFN-γ刺激成纤维细胞后，Jurkat细胞与皮肤成纤维细胞的黏附显著增加（22%的细胞黏附，而未刺激的成纤维细胞上为9%）。针对VCAM-1结构域1的单克隆抗体（mAb）可将增加的黏附抑制至未刺激的成纤维细胞水平，但针对结构域4的mAb则无此作用。针对淋巴细胞上与VCAM-1相互作用的整合素——极迟抗原-4（VLA-4）的mAb，可完全抑制Jurkat细胞与活化成纤维细胞黏附的增加，并且部分抑制其与未刺激成纤维细胞的基础黏附。这些结果表明，促炎细胞因子可在mRNA、蛋白和功能水平诱导皮肤成纤维细胞表达VCAM-1。在慢性皮肤炎症状态下，VLA-4/VCAM-1途径可能参与T淋巴细胞与活化的皮肤成纤维细胞之间的黏附相互作用。
