Platelets Contain Interleukin‐1 Alpha and Beta which are Detectable on the Cell Surface After Activation

Abstract

Activated platelets have been shown previously to exhibit membrane-bound IL-1 bioactivity, which leads to the question of localization of the cytokine in platelets. Using immunocytological and flow cytometric techniques, we found IL-1 alpha and IL-1 beta in the cytoplasma of both resting and thrombin-activated platelets. Immunogold-silver staining of the cell surface of activated platelets as well as preembedding antibody treatment of platelets revealed the presence of IL-1 (alpha and beta) in low density on the surface of intact cells in contrast to distinct enrichment in the cytoplasma of damaged platelets. Fibrin fibres present between cells indicated adsorbance of IL-1. There was also weak binding of anti-IL-1 alpha to the surface of thrombin-activated platelets as shown by flow cytometry. Following activation there appears to be some transfer of IL-1 onto the cell surface of activated cells, the bulk of the cytokine, however, is probably not released prior to platelet disintegration. In summary, we present evidence for the presence of both IL-1 alpha and IL-1 beta in resting and activated platelets without being able to demonstrate localization of the cytokines to specific subcellular structures.

Endovascular aneurysm repair reverses the increased titer and the inflammatory activity of interleukin-1α in the serum of patients with abdominal aortic aneurysm

“…However, the majority of pro-IL-1␣ is found in the plasma membrane or the nucleus of cells, 24 and it is not found in the serum of healthy people, as mIL-1␣ is usually only released extracellularly upon cell death. 25 Thus, although IL-1␣ is expressed by cells associated with pathology of AAA, ie, in platelets, 26 and in activated monocytes/macrophages, 25,27 its presence in preoperative serum was a surprising observation. However, as we were able to measure significant levels of IL-1␣ in serum, we hypothesized that it was responsible for the priming response to low dose TNF observed in cultured EC.…”

Soluble P-Selectin and Proinflammatory Cytokines in Patients with Polygenic Type IIa Hypercholesterolemia

“…0.05) levels. It is well known that IL-1ß is involved in platelet activation [14,15]. Moreover, it has recently been demon-strated that platelet-derived IL-1ß may contribute to regulation of local pathogenesis in the vessel wall by activation of the cytokine regulatory network [33].…”

“…IL-6 may, in fact, activate platelets via a mechanism involving cyclooxygenase eicosanoid metabolism [13]. Platelets, in turn, may release IL-1, which is capable of inducing endothelial secretion of IL-6 and IL-8 [14][15][16].…”

Demonstration by Flow Cytometry of the Numbers of Residual White Blood Cells and Platelets in Filtered Red Blood Cell Concentrates and Plasma Preparations

“…Immunolabeling and FC measurement of the cells collected from a total of 30 ml were car ried out as described below. [5], Therefore, finding better methods for depleting residual cells (especially WBC) before blood component storage has been a priority. Filtration methods seem to be simple and safe.…”