Comparison of Ex Vivo Expanded and Highly Purified NK Cell-Mediated Cytotoxicity Detected by 3 Different Staining Methods of Flow Cytometry / 中国实验血液学杂志

<p><b>OBJECTIVE</b>To compare the cytotoxicity of ex vivo expanded NK cells detected by flow cytometry with 3 different staining methods.</p><p><b>METHODS</b>NK cells were collected from peripheral blood on the 17day after culture. The cultured cells were divided into 3 groups: group A , B, and C. The cells in group A were stained with CFSE/Annectin-V/7-AAD; the cells in group B were stained with Annectin-V/PI, and the cells in group C cells were stained with CFSE/PI. The E:T ratios in 3 groups were 10:1, 20:1 and 40:1, respectively, the K562 cells were incubated with NK cells for 4 hrs.</p><p><b>RESULTS</b>The purity of NK cells(CD3CD56) reached to (16.34±10.51)% on day 0 and to (83.63±10.63)% on the day 17 after incubation(P<0.05); the cytotoxicity of group A was significantly higher than thay of group B at different E:T ratio (P<0.05). The cytotoxicities in A, B, C groups at E:T ratio=10:1 were (36.56±3.69)%, (10.85±2.09)% and (22.35±2.71)% respectively; the cytotoxicities in A, B, C groups at E:T ratio=9:1 were (47.83±5.52)%, (39.07±5.55)% and (29.61±4.81)%; the cytotoxicities in A, B, C groups at E:T ratio=40:1 were (67.7±4.77)%, (51.51±4.43)% and (44.12±5.62)% respectively. Meanwhile, the cytotoxicity in group A was significantly higher than that in group C at different E:T ratio (P<0.05), the percentage of cytotoxicity was (36.56±3.69)% vs (10.85±2.09)%, (47.83±5.52)% vs (29.61±4.81)%, (67.7±4.77)% vs (44.12±5.62)%, respectively.</p><p><b>CONCLUSION</b>CFSE/Annectin-V/7-AAD is able to clearly show human NK cell cytotoxicity against human tumors. Moreover, this staining technique also allows to distinguish different stages of cytotoxic killing as early and late apoptotic phase.</p>

Mechanism of MBL inhibiting the LPS-induced DC maturation / 中国实验血液学杂志

The study was aimed to investigate the mechanism of mannan-binding lectin (MBL) on bacterial lipopolysaccharide (LPS)-induced human peripheral blood monocyte-derived dendritic cell (DC) maturation. The monocytes were prepared from the peripheral blood of healthy adult volunteers. The immature dendritic cells (imDC) were induced by 5-day-culture in medium supplemented with rhGM-CSF and rhIL-4. FACS was used to investigate the interaction of MBL with imDC and the impact of MBL on LPS binding to imDC. ELISA and Western blot was used to analyze the interaction of MBL with soluble TLR4 ectodomain protein (sTLR4); Western blot was used to detect LPS-induced NF-κB translocation in imDC. The results showed that MBL could directly bind to imDC in the presence of calcium. sTLR4 protein or LPS could competitively inhibit the binding of MBL to imDC. ELISA and Western blot showed that MBL could evidently bind to sTLR4 protein in a concentration-dependent manner. FACS showed that MBL could competitively inhibit the binding of LPS to imDC by binding to imDC directly. Western blot showed that MBL decreased LPS-induced NF-κB translocation in imDC. It is concluded that MBL may competitively inhibit the binding of LPS to imDC by binding to TLR4 expressed on imDC, resulted in inhibition of LPS-induced DC maturation, suggesting that MBL can regulate DC maturation through ligand-binding. This study provides the good foundation to clarify the mechanism of MBL inhibiting the LPS-induced DC maturation.

Establishment of the tax gene expression cell lines and their biological activity / 中国实验血液学杂志

This study was aimed to establish the cell lines of human T-cell leukemia virus type-1 (HTLV-1) tax gene expression and their biological activity. The eukaryotic vector pCMV-tax and pCMV-neo-Bam were transfected into Jurkat E6-1 by using liposome, following screening with G418, the tax gene expression cell line-TaxP and the negative cell lines-TaxN were selected and enriched. Then, the mRNA expressions of LAT, SLP70, ZAP70 and NF-kappaB (p65) were measured by using RT-PCR; the NF-kappaB bioactivity was tested after transfecting the pNF-kappaB-Luc plasmids into TaxP and TaxN cells; meanwhile CD25, CD69 expressions on surface of the two cell lines were tested by flow cytometry. The results showed that TaxP and TaxN cell lines were established and the tax gene expression was detected; as compared with TaxN, the mRNA expressions of LAT, SLP70 and ZAP70 in TaxP were enhanced (p<0.05), while the NF-kappaB bioactivity in TaxP cells was stronger than that in TaxN cells (p<0.01). The CD25, CD69 on TaxP cells surface was highly expressed. It is concluded that TaxP and TaxN cell lines are established, TAX protein could promote the activation of T cells and activate the NF-kappaB pathway.