[Effects of recombinant soluble MICA protein on the biologic activities of NK cells].
OBJECTIVE
To study the effects of recombinant soluble MHC class I chain-related protein A (sMICA) on the cytotoxicity, secretion of IFN-gamma, proliferation and apoptosis of peripheral NK cells.


METHODS
After NK cells were co-cultured with recombinant soluble MICA proteins overnight, the cytotoxicity of NK cell on target cells was detected by flow cytometry. The supernant was collected to determine the concentration of IFN-gamma by ELISA. The proliferation of NK cells to sMICA was detected by MTS/PMS. NK cells were labeled with annexin V and PI to analyze their apoptosis.


RESULTS
Soluble MICA inhibited the cytotoxicity of NK cells and down-regulated the secretion of IFN-gamma, but it showed no effects on the proliferation and apoptosis of freshly isolated peripheral NK cells.


CONCLUSIONS
The soluble MICA shedding from tumor cells could be a pathway of cancer immune evasion by down-regulating the biologic activities of NK cells.
Gong
Wei-Juan
WJ
Department of Immunology, Medical School, Yangzhou University, Yangzhou 225001, China. gwj1974@263.com
Wang
Hai-Yang
HY
Fan
Min-Qi
MQ
Gong
Chun-Xiang
CX
Liu
Dan
D
Ji
Ming-Chun
MC
D000818:Animals; D017209:Apoptosis / Q000276:immunology; D049109:Cell Proliferation; D003602:Cytotoxicity, Immunologic; D015395:Histocompatibility Antigens Class I / Q000737:chemistry* / Q000276:immunology*; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D020014:K562 Cells; D007694:Killer Cells, Natural / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D011994:Recombinant Proteins / Q000737:chemistry* / Q000276:immunology*; D012995:Solubility
D015395:Histocompatibility Antigens Class I; C099187:MHC class I-related chain A; D011994:Recombinant Proteins; D007371:Interferon-gamma