Brodskyn C I, Barral A, Bulhões M A, Souto T, Machado W C, Barral-Netto M
Serviço de Imunologia, Hospital Prof. Edgar Santos, Universidade Federal da Bahia (UFBA), Brazil.
Clin Exp Immunol. 1996 Sep;105(3):450-5. doi: 10.1046/j.1365-2249.1996.d01-785.x.
There are few studies on cell-mediated cytotoxicity in human Chagas' disease. In the present study, we evaluated peripheral blood mononuclear cell (PBMC) cytotoxicity activity from chagasic patients with different clinical forms of disease. To verify the cytotoxic response, we performed cell lysis assays using 51Cr-labelled K562 cells as targets. Results are reported as lytic units (LU = number of cells required for 30% lysis) per million PBMC. Exposure of patients' PBMC to Trypanosoma cruzi antigen led to an increase in cytotoxic activity compared with unstimulated patient cells against K562. Asymptomatic cardiomyopathy patients had higher responses (37.8 +/- 5.0 LU/10(6) PBMC; mean +/- s.d.) than indeterminate (11.5 +/- 3.6 LU/10(6) and symptomatic cardiomyopathy (7.8 +/- 2.5 LU/10(6)). Normal control PBMC stimulated with T. cruzi antigen had 4.36 +/- 1.31 LU/10(6)) PBMC against K562. Addition of recombinant interferon-gamma (IFN-gamma) did not lead to significant increase in cytotoxicity in any group of patients. On the other hand, recombinant human IL-12 significantly increased cytotoxic responses from symptomatic cardiomyopathy patients and normal controls who presented low levels of cytotoxicity induced by T. cruzi antigen. The combined use of IL-12 and a neutralizing anti-IFN-gamma antibody did not change IL-12-induced cytotoxic responses, showing the direct role of this cytokine on natural killer (NK) cells. NK cells were the main cells responsible for the lysis of K562 target cells as evidenced by testing cell subsets following magnetic cell sorting. These data demonstrate that chagasic patients with different clinical forms of disease have PBMC which respond to T. cruzi antigen with a cytotoxic response, and this response is up-regulated by IL-12.
关于人类恰加斯病中细胞介导的细胞毒性的研究很少。在本研究中，我们评估了患有不同临床疾病形式的恰加斯病患者外周血单个核细胞（PBMC）的细胞毒性活性。为了验证细胞毒性反应，我们使用51Cr标记的K562细胞作为靶标进行了细胞裂解试验。结果以每百万PBMC的裂解单位（LU = 30% 裂解所需的细胞数）报告。与未刺激的患者细胞相比，患者的PBMC暴露于克氏锥虫抗原后细胞毒性活性增加。无症状性心肌病患者的反应（37.8 +/- 5.0 LU/10(6) PBMC；平均值 +/- 标准差）高于不确定型患者（11.5 +/- 3.6 LU/10(6)）和有症状性心肌病患者（7.8 +/- 2.5 LU/10(6)）。用克氏锥虫抗原刺激的正常对照PBMC对K562的反应为4.36 +/- 1.31 LU/10(6) PBMC。添加重组干扰素-γ（IFN-γ）在任何一组患者中均未导致细胞毒性显著增加。另一方面，重组人IL-12显著增加了有症状性心肌病患者和由克氏锥虫抗原诱导的细胞毒性水平较低的正常对照的细胞毒性反应。IL-12与中和性抗IFN-γ抗体联合使用并未改变IL-12诱导的细胞毒性反应，表明该细胞因子对自然杀伤（NK）细胞具有直接作用。磁珠细胞分选后检测细胞亚群表明，NK细胞是负责裂解K562靶细胞的主要细胞。这些数据表明，患有不同临床疾病形式的恰加斯病患者的PBMC对克氏锥虫抗原产生细胞毒性反应，且该反应受IL-12上调。
