KHEIRANDISH M, EBTEKAR M, POURFATHOLLAH A, HASSAN Z, KAZEM NEJAD A. THE CYTOTOXICITY PATHWAY OF NATURAL KILLER CELLS IN CORD BLOOD COMPARED TO P ERIPHERAL BLOOD. Med J Islam Repub Iran 2004; 18 (1) :55-60
URL:
http://mjiri.iums.ac.ir/article-1-653-en.html
From the Department of Immunology School of Medical Sciences, Tarbiat Modalres University, Tehran, and the Iranian Blood Transfusion Research Center, Tehran, Iran. , kheira_m2001@yahoo.co.uk
Abstract: (5764 Views)
The cytotoxic activity of natural killer cells is usually tested by radioactive assay
CSI Cr release assay), which detects the release of cytoplasmic contents after plasma
membrane disintegration of dying cells. In contrast to this indirect evaluation of cytotoxicity,
the assessment of cell damage by flow cytometry aims to provide a more exact
characterization of the death pathway via detection of the percentage of apoptosis and
necrotic cells. Annexin V-FITC (Axv -FITC) can be used to label cells in the early
apoptotic state, while propidiurn iodide (PI) indicates late apoptosis or necrosis.
The NK cytotoxicity of cord blood (CB) and peripheral blood (PB) was determined
after 4 hours of incubation in the absence of cytokines. After 4 hours in vitro
incubation, co-staining with Annexin V-FITC (Axv-FITC) and propidiurn iodide (PI)
pelmitted discrimination between viable, early apoptotic and necrotic cells. As we would
expect, the cytotoxicity pathway in PB mononuclear cells (MNCs) consists of both
apoptosis and necrosis pathways but in CB MNCs it almost consists of early apoptosis
and necrosis is negligible. With escalating E: T (effector: target) ratio changes in the
percentage of apoptotic cells in PB samples were significantly higher than CB samples.
The mechanism( s) of the low cytotoxicity of resting cord NK cells is not welllmderstood.
Complementary research in this field is recognized to elucidate the phenotypical
and functional properties of CB cells and how they relate to maturational stages. CB
studies are important for transplantation research and may provide insight to the suppressive
mechanism by which the host -recipient could evade GVHD and rejection.