Search results for "Platelet Factor 4"

Interferon-regulatory factor 4 is essential for the developmental program of T helper 9 cells.

2010

Summary Interferon-regulatory factor 4 (IRF4) is essential for the development of T helper 2 (Th2) and Th17 cells. Herein, we report that IRF4 is also crucial for the development and function of an interleukin-9 (IL-9)-producing CD4 + T cell subset designated Th9. IRF4-deficient CD4 + T cells failed to develop into IL-9-producing Th9 cells, and IRF4-specific siRNA inhibited IL-9 production in wild-type CD4 + T cells. Chromatin-immunoprecipitation (ChIP) analyses revealed direct IRF4 binding to the Il9 promoter in Th9 cells. In a Th9-dependent asthma model, neutralization of IL-9 substantially ameliorated asthma symptoms. The relevance of these findings is emphasized by the fact that the ind…

Dynamics of CXC group chemokine platelet factor 4 (PF4) plasma levels in non-small cell lung cancer (NSCLC)

2012

CXC chemokines display pleiotropic effects participating not only in inflammation, but regulating angiogenesis and metastatic spread in cancer. Platelet factor 4 (PF4) is a 70-amino acid protein belonging to the CXC chemokine family. PF4 is also known as CXCL4. This chemokine is released from alpha-granules of activated platelets and binds with high affinity to heparin-like molecules promoting coagulation. Megakaryocytes respond to the presence of tumors by increasing their number in the bone marrow accompanied by increase in the number of platelets in circulation, causing changes in chemokine balance.

A retrospective analysis of immunohistochemical determined IRF4 (interferon regulating factor 4) expression in a consecutive cohort of 114 ovarian ca…

2018

Insights in ChAdOx1 nCoV-19 vaccine-induced immune thrombotic thrombocytopenia

2021

Abstract SARS-CoV-2 vaccine ChAdOx1 nCoV-19 (AstraZeneca) causes a thromboembolic complication termed vaccine-induced immune thrombotic thrombocytopenia (VITT). Using biophysical techniques, mouse models, and analysis of VITT patient samples, we identified determinants of this vaccine-induced adverse reaction. Super-resolution microscopy visualized vaccine components forming antigenic complexes with platelet factor 4 (PF4) on platelet surfaces to which anti-PF4 antibodies obtained from VITT patients bound. PF4/vaccine complex formation was charge-driven and increased by addition of DNA. Proteomics identified substantial amounts of virus production-derived T-REx HEK293 proteins in the ethyle…

Introducing the new biomarker research approach into practice: Preliminary data from CXCL4 chemokine study in non-small cell lung cancer (NSCLC)

2012

P-147PLASMA PLATELET FACTOR 4 AS PREDICTOR OF ANGIOGENIC ACTIVITY: DIAGNOSTIC AND PROGNOSTIC TOOL FOR EARLY STAGE NON-SMALL CELL LUNG CANCER

2013

Staphylococcus aureus alpha-toxin attack on human platelets promotes assembly of the prothrombinase complex.

1990

alpha-Toxin, the major cytolysin of Staphylococcus aureus, promotes blood coagulation by its attack on human platelets (Bhakdi S., Muhly, M., Mannhardt, U., Hugo, F., Klapettek, K., Mueller-Eckhardt, C., and Roka, L. (1988) J. Exp. Med. 168, 527-542). In the present study we demonstrate that toxin attack on gel-filtered human platelets initiates the assembly of prothrombinase complexes at rates up to 10-fold of controls. Treatment of platelets with 0.1 microgram/ml alpha-toxin resulted in generation of 1.4 units of thrombin/10(8) platelets. A similar rate of thrombin generation was noted when platelets were subjected to three cycles of freezing and thawing. However, the alpha-toxin-induced …

Plasma markers of platelet and polymorphonuclear leukocyte activation in young adults with acute myocardial infarction

2005

Our goal was to evaluate some plasma markers of platelet and polymorphonuclear leukocyte (PMN) activation in a group of young adults with acute myocardial infarction (AMI) at the initial stage and after three months. We enrolled 49 AMI subjects aged<45 years and examined plasmatic levels of platelet factor 4 (PF4), β-thromboglobulin (β-TG), elastase and myeloperoxidase (MPO) using ELISA methods. PF4 and β-TG were increased, compared to control subjects, both at the initial stage and after 3 months. In control subjects and in AMI patients, at both times of observation, there was a significant and positive correlation between the two platelet parameters, while no correlation was present betwe…