Premium
Spontaneous apoptosis in neutrophils is associated with downregulation of HLA Class I and is prevented by ligation of Class I
Author(s) -
Frumento Guido,
Ottonello Luciano,
Bertolotto Maria,
Franchello Silvia,
Melioli Giovanni,
Dallegri Franco
Publication year - 2000
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1189/jlb.68.6.873
Subject(s) - biology , downregulation and upregulation , class (philosophy) , apoptosis , immunology , ligation , human leukocyte antigen , microbiology and biotechnology , cancer research , genetics , antigen , gene , computer science , artificial intelligence
In many types of cells, ligation of human leukocyte antigens (HLA) Class I molecules with specific mAbs results in the transduction of signals that trigger different cell functions. We have investigated the effects of Class I ligation in human neutrophils. After several hours in culture, neutrophils split spontaneously into two subpopulations, one with normal and the other with reduced levels of Class I. The latter subpopulation displayed high binding capacity for Annexin V, showed a hypodiploid peak, electrophoretic DNA fragmentation, and morphological features of apoptotic cells. The addition of drugs known to delay apoptosis (GM‐CSF or cAMP) resulted in a reduction of Class I modulation. Furthermore, ligation of surface Class I with F(ab′) 2 fragments of the anti‐Class I mAb W6/32 resulted in a delay in the progression of apoptosis. These data indicate that this surface Class I molecule is a marker of age‐related apoptosis, and the ligation of these molecules results in the transduction of a signal that inhibits apoptosis. Thus, the downregulation of HLA Class I molecules in aging neutrophils prevents their halting the apoptotic process.