Granulocyte-macrophage colony-stimulating factor modulates tapasin expression in human neutrophils

Differential display-polymerase chain reaction (DD-PCR) was used to evaluat e changes in mRNA expression of granulocyte-macrophage colony-stimulating f actor (GM-CSF) treated human neutrophils to better understand how this cyto kine affects the functions of neutrophils at the molecular level. Although a variety of cDNA fragments were identified as modulated by GM-CSF with the use of DD-PCR, one fragment in particular, NGS-17 (neutropllil GM-CSF-stim ulated fragment #17), was characterized, The NGS-17 fragment hybridized to a 3,8-kb mRNA that encodes for a protein of a predicted molecular mass of 4 7,6 kDa. After cloning and sequencing, this gene was found to code for the recently sequenced tapasin or TAP-A protein. Immunoprecipitation and immuno blotting studies using anti-tapasin antibodies showed that tapasin is expre ssed in neutrophils and is associated with the MHC class I-TAP complex, Mor eover, tapasin expression was found to be induced by dimethyl sulfoxide and by retinoic acid in HL-60 cells. This is the first report on the expressio n of tapasin in human neutrophils, It provides novel information, at the mo lecular level, on how GM-CSF enhances the functions of these cells.