Influence of human cytomegalovirus on the expression of natural-killer group 2-members receptors on the natural killer cells

ABSTRACT

Objective To examine the effect of human cytomegalovirus (CMV) on the expressions of natural killer group 2 members (NKG2),including natural-killer group 2-member A (NKG2A),natural-killer group 2-member C (NKG2C) and natural-killer group 2 member D (NKG2D) receptors on the natural killer (NK) cells.Methods NK cells were isolated from the peripheral blood mononuclear cells of 20 healthy individuals using EasySep magnetic beads.NK cells and CMV-infected human embryonic lung fibroblast (HELF) were co-cultured for 24 h and regarded as experimental group.While CMV-uninfected NK cells co-cultured with HELF and only NK cells were taken as control groups.Flow cytometry was used to detect the expressions of the NK cell receptors in experimental and control groups.The comparison between groups was done by Wilcoxon rank sum test.Results The percentages of NK cells expressing NKG2C and NKG2D in group of CMV-infected NK cells co-cultured with HELF were 34.26％±7.99％ and 24.94％ ± 5.24％,respectively,which were significantly higher than those in CMVuninfected NK cells co cultured with HELF (26.31％ ±6.41％; Z=-3.285,P=0.001 and 20.02％±6.80％ ; Z=-3.285,P=0.001,respectively) and NK cells alone (25.78％± 6.62％ ; Z=-3.211,P=0.001 and 20.12 ％ ± 6.75 ％ ; Z=-3.285,P =0.001,respectively),while no significant changes were found in the expressions of the two receptors between groups of CMV-uninfected NK cells co-cultured with HELF and NK cells alone (both P＞0.05).Moreover,no significant changes were found in the expression of NKG2A among groups (all P＞0.05).The levels of NKG2A+ NKG2C,NKG2A+NKG2D,NKG2C+ NKG2A-and NKG2D+ NKG2A-cells in CMV infected NK cells co-cultured with HELFgroup were 2.99％ ±2.62％,6.13％±2.44％,26.62％ ±7.63％ and 20.44％±5.68％,respectively,while those in group of CMV-uninfected NK cells co-cultured with HELF were 4.44％ ± 4.25％ (Z=-2.240,P=0.025),6.99％±2.33％ (Z=-2.053,P=0.040),19.52％±6.80％ (Z=-2.800,P=0.005) and 15.78％±7.48％ (Z=-2.875,P=0.004),respectively.However,no significant changes were found in the expressions of NKG2A+ NKG2C+ and NKG2A+ NKG2D+ among groups (all P＞0.05).Conclusions CMV infection may change the NK receptor expressions,then stimulatory NKG2C and NKG2D signal transductions are enhanced and the inhibitory NKG2A signal conduction is weakened during CMV infection.