Mesenchymal stem cells (MSCs) can inhibit T cell proliferation, the effects of MSCs on various T cell subsets have showed different immune regulatory reactions, and their mechanisms mainly include cell-cell contact and mediation by cytokines secreted from MSCs. Encouragingly, recent studies have showed that the effects of MSCs on T-cell response to pathogens is not significant, but can obviously suppress T cell response to allogeneic antigens. In addition, MSCs can regulate the proliferation, survival, antibody secretion and differentiation of B cells, inhibit the production, proliferation, migration and antigen-presentation of DCs, and modulate the differentiation and maturation of DCs, and regulate the proliferation, cell toxicity and cytokine secretion of NK cells. In this review, the research advances on immunomodulatory effects of MSCs on various immune cells including T-lymphocytes, B-lymphocytes, NK cells and DCs are summarized with emphasis on the immunoregulatory effects of MSCs on T-lymphocytes.
B-Lymphocytes ; immunology ; Dendritic Cells ; immunology ; Humans ; Killer Cells, Natural ; immunology ; Mesenchymal Stromal Cells ; cytology ; immunology ; T-Lymphocytes ; immunology

OBJECTIVESTo evaluate the effects of K562-dendritic cell (DC) and Raji-DC fusion vaccines on the cytotoxicity of cord blood (CB) derived cytokine-induced killer/natural killer (CIK/NK) cells.

METHODSDC and CIK/NK cells were derived from CB mononuclear cells. CB-DC were fused with inactivated K562 or Raji cells by PEG to form K562 or Raji-DC fusion vaccine. The CIK/NK cells stimulated by different co-culture antigens were three groups: K562-DC or Raji-DC fusion vaccine group, inactivated K562 or Raji plus DC group, and CB-DC alone group. The cytotoxicity of CIK/NK cells stimulated by different co-culture antigens was measured by MTT test.

RESULTSAll the antigens used for stimulation could enhance the cytotoxicity of CB-CIK/NK cells, with no specificity difference. At 20:1 effector-target ratio, the cytolytic activities of K562-DC and Raji-DC fusion vaccine groups against Raji cells were (75.44 +/- 4.19)% and (81.33 +/- 4.18)% respectively (P < 0.05); and that of inactivated K562 + DC and Raji + DC group against Raji cells were (73.12 +/- 4.22)% and (80.49 +/- 4.27)%, respectively (P < 0.01). There was no significant difference in the cytotoxicity to K562 cells between the two fusion vaccine groups (P > 0.05). The cytotoxicity of CB-CIK/NK cells immunized by Raji cells was higher than that by K562 cells. In CIK/NK cells co-stimulated by the same tumor antigen, there was no significant difference in the cytotoxicity between DC fusion vaccine group and inactivated cells plus DC group to different tumor cells.

CONCLUSIONSThe cytotoxicity of CB-CIK/NK cells to tumor cells was not specific. There was no significant difference in the cytotoxic activity of CB-CIK/NK cells between the DC fusion vaccine group and inactivated cells plus DC group.

Cancer Vaccines ; immunology ; pharmacology ; Cells, Cultured ; Cytotoxicity, Immunologic ; Dendritic Cells ; immunology ; Fetal Blood ; cytology ; Humans ; K562 Cells ; Killer Cells, Lymphokine-Activated ; immunology ; Killer Cells, Natural ; immunology

The activity of the NK cells in patients with preeclampsia was studied to investigate the pathogenesis of preeclampsia. By using MTT and 51Cr releasing technique, the proliferation and killing ability of the NK cells in maternal and umbilical blood from preeclampsia patients (n = 18) and normal third trimester pregnant women (n = 18) were detected. The NK-92 cell line was as the positive control. The results showed that the NK cell counts of umbilical blood in preeclampsia patients and normal third trimester pregnant women were significantly greater than those of maternal blood (both P<0.05). Compared with that in normal third trimester pregnant women, the proliferative ability of the NK cells in preeclampsia patients was apparently increased (P<0.05). Compared with that in maternal blood, the proliferative ability of the NK cells in umbilical blood from both preeclampsia patients and normal third trimester pregnant women was dramatically increased. The killing ability of the NK cells in preeclampsia patients was significantly higher than that in normal third trimester pregnant women (P <0.05). It was suggested that both number and function of the NK cells in preeclampsia women were increased, and that in umbilical blood was greater than that in maternal blood, speculating that the function of the NK cells may affect the maintenance of the maternal and fetal immune tolerance during pregnancy.
Cytotoxicity, Immunologic/*immunology ; Fetal Blood/cytology ; Immune Tolerance ; Killer Cells, Natural/*immunology ; Killer Cells, Natural/pathology ; Pre-Eclampsia/blood ; Pre-Eclampsia/*immunology ; Pregnancy Trimester, Third

OBJECTIVETo investigate the apoptosis of NK cells induced by the erythroleukemia cell line K562 in vitro.

METHODSPrimary NK cells isolated from the peripheral blood of healthy donors by magnetic-activated cell sorting were cultured with stem cell medium containing recombinant human interleukin-2 (rhIL-2). The NK cells and K562 cells were mixed and co-cultured at different E:T ratios for different time lengths. The apoptosis of NK cells and K562 cells were detected using PE-AnnexinV/7-AAD labeling and flow cytometry.

RESULTSThe purity of isolated NK cells reached (93.99∓4.22)%. At the same E: T ratio, the apoptotic rate of NK cells induced by K562 cells increased significantly with time. As the E:T ratio reduced, the apoptotic rate of the NK cells increased and their cytotoxic activity against K562 cells was attenuated.

CONCLUSIONK562 cells can induce the apoptosis of activated NK cells, which is one of the probable mechanisms of immune escape of tumors.

Apoptosis ; Cytotoxicity, Immunologic ; Humans ; K562 Cells ; Killer Cells, Natural ; cytology ; immunology ; Tumor Escape

OBJECTIVETo observe the effect of mesenchymal stem cells derived from umbilical cord (UC-MSCs) on natural killer (NK) cells-mediated cytotoxicity against dendritic cells (DCs) and explore the mechanism.

METHODSMSCs were isolated from human umbilical cord by collagen digestion and cultured in vitro. NK cells were separated from healthy human peripheral blood by magnetic bead sorting. Mononuclear cells from healthy human peripheral blood were cultured in the presence of granulocyte and macrophage colony stimulating factor (GM-CSF) and interleukin-4 (IL-4) to obtain the immature DCs. The DCs were then co-cultured with UC-MSCs in the presence of tumor necrosis factor α (TNFα) for 2 days, and the expressions of CD11c and CD86 on DCs and IL-12 level in the culture medium was detected using flow cytometry and ELISA, respectively. The cytotoxicity of NK cells against DCs was analyzed by LDH-releasing assay, and the expressions of ligands for killer activator receptor (MICA/B and ULBP1-3) on the DCs were detected with flow cytometry.

RESULTSCompared with the cytokine-induced DCs, the DCs induced by co-culture with UC-MSCs showed an identical CD11c expression but lowered CD86 expression and IL-12 secretion. The natural killer cells produced a stronger cytotoxicity against UC-MSCs-induced DCs than against cytokine-induced DCs. The UC-MSCs-induced DCs also showed increased expressions of MICA and MICB on the surface.

CONCLUSIONUC-MSCs can enhance NK cells-mediated cytotoxicity against DCs possibly by inhibiting DC maturation and up-regulating the ligands for killer activator receptor on the surface of the DCs.

Cells, Cultured ; Cytotoxicity, Immunologic ; immunology ; Dendritic Cells ; cytology ; immunology ; Humans ; Killer Cells, Natural ; cytology ; Mesenchymal Stromal Cells ; cytology ; Umbilical Cord ; cytology

AIMTo investigate the effect of acetylcholine (ACh) on the cytotoxicity of natural killer (NK) cells and to explore the receptor mechanisms involved in the effect.

METHODSThe effector cells (i. e. NK cells) from the spleens of rats were collected and cultured with the target cells (Yac-1 cells). The various concentrations of ACh, cholinergic receptor agonists or antagonists were added to the cultures, respectively according to distinct experimental purposes. Lactate dehydrogenase (LDH) release assay was used to evaluate NK cell cytotoxicity.

RESULTSNK-cell-mediated lysis of Yac-1 lymphoma cells was reduced by 10(-10) - 10(-6) mol/L ACh. The inhibitory effect of ACh on NK cell cytotoxicity was mimicked by pilocarpine, an agonist of muscarinic receptor, and by nicotine, an agonist of nicotinic receptor, at all applied concentrations (10(-10) - 10(-6) mol/L). Muscarinic receptor antagonist atropine blocked the inhibitory effect of ACh on the cytotoxicity of NK cells. Nevertheless, tubocurarine, an antagonist of nicotinic receptor, had no blocking effect on the suppression of NK cell cytotoxicity by ACh.

CONCLUSIONACh results in an inhibition of the cytotoxicity of NK cells, and this inhibition is realized mainly through M and N1 cholinergic receptor.

Acetylcholine ; pharmacology ; Animals ; Cells, Cultured ; Female ; Killer Cells, Natural ; cytology ; drug effects ; immunology ; Male ; Rats ; Receptors, Natural Killer Cell ; drug effects

OBJECTIVETo prepare tumor antigen peptides from HL-60 cells and to induce specific immune response.

METHODSHL-60 antigen peptides were obtained using techniques including freezing and thawing, heat precipitation and acid precipitation. The stimulating effect of the in vitro Hsp70 binding HL-60 peptides on PBMC and the proliferation of stimulated PBMC were observed by T cell activation test. The cytotoxicity of proliferated PBMC is detected by incubating HL-60 cells or K562 cells with PBMC respectively.

RESULTSThe obtained tumor antigen peptides were a peptides mixture. The mixed peptides could activate PBMC and cause PBMC proliferation in vitro after presented by Hsp70. The proliferated PBMC showed specific cytotoxicity to HL-60 cells but not to K562 cells.

CONCLUSIONThe method for preparing of human leukemia tumor antigen peptides used in this paper is simple and easy; the obtained antigen peptides can induce specific immune response in vitro.

Cell Division ; HL-60 Cells ; HSP70 Heat-Shock Proteins ; immunology ; Humans ; K562 Cells ; Killer Cells, Natural ; immunology ; Leukocytes, Mononuclear ; cytology ; immunology ; Neoplasm Proteins ; immunology ; Peptides ; immunology

OBJECTIVETo investigate the changes in natural killer (NK) cell count in the peripheral blood of asthmatic patients.

METHODSThe number of NK cells in the peripheral blood was determined with flow cytometry in 63 asthmatic patients with acute episodes, 65 patients with stable asthma and 62 healthy nonatopic subjects.

RESULTSA significant decrease in NK cell number was noted in asthmatic patients during acute exacerbation [(13.9-/+9.4) %] in comparison with patients with stable asthma [(22.5-/+12.3) %] and healthy subjects [(19.6-/+10.1)%] (P<0.05), and the NK cell number showed no significant difference between the latter two groups (P>0.05).

CONCLUSIONNK cell number is reduced in acute exacerbation of asthma, suggesting its important role in the asthmatic process.

Adult ; Asthma ; blood ; immunology ; Cell Count ; methods ; Female ; Flow Cytometry ; Humans ; Killer Cells, Natural ; cytology ; immunology ; Male ; Middle Aged

The objective of this study was to investigate the effect of dendritic cells (DCs) on expansion and function of autologous natural killer (NK) cells and its mechanism in vitro. NK cells were expanded from peripheral blood mononuclear cells (PBMNCs) of healthy volunteers in stem cell growth medium (SCGM) supplemented with rhIL-2 (control group) in 24-well culture plates at 37 degrees C in a humidified CO(2)-containing atmosphere. NK cells were cultured with autologous DCs in the ratio of 5 to 1 (group 5:1) or 1 to 1 (group 1:1) from day 10 after expansion. Total cells of every group were counted and the expression of CD3, CD16/56 on the surface of NK cells was assayed by flow cytometry on days 7, 14 and 21 to calculate the expansion of NK cells. Cytotoxicity of expanded NK cells against K562 cells was assayed by MTT method. TNF-alpha and IL-12p70 were detected in culture supernatants by sandwich ELISA. The results indicated that the expansion and cytotoxicity of NK cells were improved after mixed with autologous DCs. Furthermore, when DCs were mixed with NK cells, the ratio of DCs to NK cells was higher, the expansion and cytotoxicity NK cells were higher. On day 14, the expansion multiple in control, group 5:1 and group 1:1 were 16.26 +/- 1.58, 29.25 +/- 4.01 and 21.23 +/- 2.91 respectively. The expansion multiple of group 5:1 was much higher than that of the other two groups (p < 0.05). The expressions of CD3(-), CD56/16(+) on surface of NK cells in control, group 5:1, group 1:1 were (34.8 +/- 5.1)%, (64.6 +/- 7.8)% and (50.6 +/- 8.7)% respectively and that of group 5:1 was the highest (p < 0.05). The cytotoxicities against K562 cells in control, group 5:1 and group 1:1 were (63.7 +/- 3.8)%, (87.4 +/- 6.8)% and (75.4 +/- 6.3)% respectively. The cytotoxicity of group 5:1 was higher than that in the other two groups also (p < 0.05). TNF-alpha and IL-12p70 levels in culture supernatants when DCs and NK cells were mixed in the ratio of 5 to 1 were much higher than those in culture supernatants of DCs and NK cells alone or in culture supernatants when DCs and NK cells were mixed in the ratio of 1 to 1 (p < 0.05). It is concluded that the expansion and cytotoxicity of NK cells can be improved by DCs and it depended on the mixed ratio of DCs to NK cells. The elevated expansion of NK cells by DCs bears relation to IL-12 produced by DCs. The enhanced cytotoxicity of NK cells is associated with TNF-alpha secreted by NK cells.
Cells, Cultured ; Coculture Techniques ; Dendritic Cells ; cytology ; immunology ; Humans ; Interleukin-2 ; secretion ; Killer Cells, Natural ; cytology ; immunology ; Tumor Necrosis Factor-alpha ; secretion

OBJECTIVETo study the impacts of HIV/HCV co-infection to NK cells by investigating the changes of frequencies and functions of NK cells in HIV/HCV co-infected patients.

METHODSFrequencies and counts of NK cells were measured in patients with HIV mono-infection, HCV monoinfection, HIV/HCV co-infection and health control (HC) group by flow cytometer (FCM). After stimulated with PMA and K562 cells, PBMCs were examined the proportion of IFN-gamma+ NK cells by FCM. Proportion of killed K562 cells were detected to analyze the killing functions of NK cells.

RESULTSThe frequencies of NK cells, the percentages of IFN-gamma+ NK cells as well as the functions of NK cells killing the K562 cells in HIV/HCV co-infection, HIV mono-infection and HCV mono-infection groups were all lower than those of HC group significantly, the absolute counts and killing functions of NK cells in co-infection group were significantly lower than those of HIV or HCV mono-infection group.

CONCLUSIONSThe counts and functions of NK cells were affected more in HIV/HCV co-infections than those in HIV or HCV mono-infection.

Case-Control Studies ; Cell Count ; Coinfection ; immunology ; Flow Cytometry ; HIV Infections ; immunology ; Hepatitis C ; immunology ; Humans ; K562 Cells ; Killer Cells, Natural ; cytology ; immunology