4-1BBL分子在人急性单核细胞白血病细胞系U937和SHI-1的表达及促生长作用

Co-stimulation 4-1BB ligand induces proliferation and cytokine production in human acute monocytic leukemia cell lines U937 and SHI-1

目的研究4-1BBL分子在人急性单核细胞白血病细胞系U937和SHI-1的表达及促生长作用。方法用流式细胞术(FCM)和RT-PCR法检测4-1BBL分子在U937、SHI-1细胞系的表达;将激发型4-1BBL单抗(1F1)与U937、SHI-1细胞系分别进行培养,细胞计数分析2个细胞系的生长情况;收集U937细胞的培养上清,ELISA法检测细胞因子。结果FCM测得U937和SHI-1细胞有4-1BBL分子表达,RT-PCR法测得4-1BBLmRNA;细胞计数表明,1F1明显促U937、SHI-1细胞系生长(P<0·01);ELISA示1F1与U937细胞共培养48h,其上清液中IL-6含量(55·91±10·23)pg/ml,显著高于IgG1同型对照组的(12·14±3·8)pg/ml(P<0·01)。结论U937和SHI-1细胞系组成性表达4-1BBL分子;1F1与U937、SHI-1细胞的4-1BBL分子交联后,可促进U937、SHI-1细胞系生长,诱导U937细胞分泌细胞因子IL-6。

Objective To study the expression and function of 4-1BBL in human acute monocytic leukemia cell lines U937 and SHI-1. Methods The expression of 4-1BBL protein was detected by FACS and the expression of 4-1BBL mRNA on U937 and SHI-1 cells was detected by RT-PCR Anti-4-1BBL mAb 1F1 was used to stimulate U937 and SHI-1. Cell proliferation was determined by cell counts. The production of cytokines was determined by a cytokine-specific ELISA of the culture supernatants of U937 cells. Results 4-1BBL molecule was constitutively expressed on U937 and SHI-lcells. Anti-4-1BBL mAb 1F1 could stimulate the proliferation of U937 and SHI-1 cell lines. The levels of IL-6 in the supernatants of U937 cells treated with anti-4-1BBL mAb 1F1 and isotype IgG1 for 48 hours were 55.91 q- 10.23 pg/ml and 12. 14± 3.8 pg/ml, respectively（P〈0.01）. Conclusion 4-1BBL is constitutively expressed on monocytic leukemia cell lines U937 and SHI-1. 4-1BBL reverse signaling plays a critical role in moncytic hematologic cells survival and growth, and contributes to cytokine IL-6 release.