Engagement of the Lewis X antigen (CD15) results in monocyte activation
| Autor: | S K, Lo, D T, Golenbock, P M, Sass, A, Maskati, H, Xu, R L, Silverstein |
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| Rok vydání: | 1997 |
| Předmět: |
Cell Nucleus
Inflammation Tumor Necrosis Factor-alpha Recombinant Fusion Proteins Antibodies Monoclonal Lewis X Antigen Transfection Polymerase Chain Reaction Monocytes Cell Line Gene Expression Regulation Immunoglobulin M Genes Reporter Humans Endothelium Vascular Immunologic Capping RNA Messenger Interleukin-1 Signal Transduction Transcription Factors |
| Zdroj: | Blood. 89(1) |
| ISSN: | 0006-4971 |
| Popis: | We previously reported that monocyte adhesion to tumor necrosis factor-alpha (TNF-alpha)-treated endothelial cells increased expression of tissue factor and CD36 on monocytes. Using immunological cross-linking to mimic receptor engagement by natural ligands, we now show that CD15 (Lewis X), a monocyte counter-receptor for endothelial selectins may participate in this response. We used cytokine production as a readout for monocyte activation and found that CD15 cross-linking induced TNF-alpha release from peripheral blood monocytes and cells from the monocytic cell line MM6. Quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) showed an increase in steady-state TNF-alpha mRNA after 3 to 4 hours of cross-linking. CD15 cross-linking also concomitantly increased interleukin-1 beta (IL-1 beta) mRNA, while no apparent change was observed in the levels of beta-actin mRNA, indicating specificity. To examine transcriptional regulation of cytokine genes by CD15 engagement, a CAT plasmid reporter construct containing IL-1 beta promoter/enhancer sequences was introduced into MM6. Subsequent cross-linking of CD15 increased CAT activity. CD15 engagement by monoclonal antibody also attenuated IL-1 beta transcript degradation, demonstrating that signaling via CD15 also had posttranscriptional effects. Nuclear extracts of anti-CD15 cross-linked cells demonstrated enhanced levels of the transcriptional factor activator protein-1, minimally changed nuclear factor-kappa B, and did not affect SV40 promoter specific protein-1. We conclude that engagement of CD15 on monocytes results in monocyte activation. In addition to its well-recognized adhesive role, CD15 may function as an important signaling molecule capable of initiating proinflammatory events in monocytes that come into contact with activated endothelium. |
| Databáze: | OpenAIRE |
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