转化生长因子-β_1对活化巨噬细胞杀伤阿米巴原虫的作用

Effects of Transforming Growth Factor β 1 on Amebicidal Activity of Activated Macrophage

活化巨噬细胞产生的一氧化氮（ＮＯ）是抗阿米巴原虫的主要效应分子。转化生长因子（ＴＧＦ－β１）能够调节巨噬细胞的许多机能，包括ＮＯ产量。本文探讨ＴＧＦ－β１对活化巨噬细胞体外杀伤溶组织内阿米巴滋养体的效力和ＮＯ产量及其合酶（ｍａｃ－ＮＯＳ）ｍＲＮＡ的表达与其相互关系。方法Ｂａｌｂ／ｃ小鼠骨髓巨噬细胞（ＢＭＭ）的ＮＯ产量用Ｇｒｉｅｓｓ方法检测；ｍａｃ－ＮＯＳｍＲＮＡ表达水平用ＲＮＡ印迹分析；ＢＭＭ杀伤溶组织内阿米巴滋养体的效力用台盼蓝排斥实验检测。结果（１）ＴＧＦ－β１本身不能直接诱导ＢＭＭ杀伤阿米巴效力、ＮＯ产生及ｍａｃ－ＮＯＳｍＲＮＡ表达；（２）ＴＧＦ－β１预处理则可引动ＢＭＭ对γ－干扰素（ＩＦＮ－γ）＋肿瘤坏死因子－α（ＴＮＦ－α）／脂多糖（ＬＰＳ）激活的应答能力：提高其杀伤阿米巴效力达１５％和２３％，且ＮＯ产量相应增加８５％和２７％；（３）经ＲＮＡ印迹分析，ＴＧＦ－β１预处理的ＢＭＭＮＯ产量的提高伴随着高水平的ｍａｃ－ＮＯＳｍＲＮＡ表达；（４）在固定浓度ＩＦＮ－γ的存在情况下，ＴＧＦ－β１对ＮＯ产量的引动作用主要依赖激活信号ＴＮＦ－α和ＬＰＳ的剂量。结论ＴＧＦ－β１预处理可引动ＢＭＭ增加ｍａｃ－ＮＯＳｍ?

Objective\ The present study was aimed at investigating the effect of transforming growth factor β 1(TGF β 1) on activated macrophage nitric oxide synthase(mac NOS) mRNA expression and nitric oxide(NO) production for amebicidal activity.\ Methods\ Bone marrow derived macrophage(BMM) was obtained from punctured femoral bone of female Balb/c mice.\ NO production was measured by nitrite according to the Griess reaction and expression of mac NOS mRNA was determined by Northern blot analysis.\ Results\ TGF β 1 by itself was incapable of inducing BMM amebicidal activity and NO production as well as mac NOS mRNA expression.\ In contrast,TGF β 1 pretreatment(4 hr) primed BMM for an enhanced amebicidal activity by 15% and 23% in response to IFN γ+TNF α/LPS,concomitant with increased NO production by 85% and 27%,respectively. TGF β 1 pretreatment increased NO production by IFN γ+TNF α/LPS stimulation in a time and dose dependent manner.\ By Northern blot analysis,the increased NO production of TGF β 1 pretreated BMM was preceded by markedly enhanced expression of the mac NOS mRNA. The prime effect of TGF β 1 on NO production was critically dependent on both LPS(≥100 ng/ml) and TNF α(≥100 U/ml) triggering dose in the presence of IFN γ(100 U/ml).\ Conclusion\ These results demonstrate that TGF β 1 can prime BMM for increased mac NOS mRNA expression for NO dependent amebicidal activity.