Cardoso Thiago Marconi, Machado Álvaro, Costa Diego Luiz, Carvalho Lucas P, Queiroz Adriano, Machado Paulo, Scott Phillip, Carvalho Edgar M, Bacellar Olívia
Serviço de Imunologia, Hospital Universitário Prof. Edgard Santos, Universidade Federal da Bahia, Salvador, BA, Brazil Instituto Nacional de Ciência e Tecnologia de Doenças Tropicais (INCT-DT) (CNPq/MCT), Salvador, BA, Brazil.
Serviço de Imunologia, Hospital Universitário Prof. Edgard Santos, Universidade Federal da Bahia, Salvador, BA, Brazil.
Infect Immun. 2015 Mar;83(3):898-906. doi: 10.1128/IAI.02404-14. Epub 2014 Dec 22.
Cutaneous leishmaniasis (CL) caused by Leishmania braziliensis is characterized by a strong Th1 response that leads to skin lesion development. In areas where L. braziliensis transmission is endemic, up to 15% of healthy subjects have tested positive for delayed-type hypersensitivity to soluble leishmania antigen (SLA) and are considered to have subclinical (SC) infection. SC subjects produce less gamma interferon (IFN-γ) and tumor necrosis factor alpha (TNF-α) than do CL patients, but they are able to control the infection. The aim of this study was to characterized the role of CD8(+) T cells in SC infection and in CL. Peripheral blood mononuclear cells (PBMC) were stimulated with SLA to determine the frequencies of CD4(+) IFN-γ(+) and CD8(+) IFN-γ(+) T cells. Monocytes from PBMC were infected with L. braziliensis and cocultured with CD8(+) T cells, and the frequencies of infected monocytes and levels of cytotoxicity markers, target cell apoptosis, and granzyme B were determined. The frequency of CD8(+) IFN-γ(+) cells after SLA stimulation was higher for SC individuals than for CL patients. The frequency of infected monocytes in SC cells was lower than that in CL cells. CL CD8(+) T cells induced more apoptosis of infected monocytes than did SC CD8(+) T cells. Granzyme B production in CD8(+) T cells was higher in CL than in SC cells. While the use of a granzyme B inhibitor decreased the number of apoptotic cells in the CL group, the use of z-VAD-FMK had no effect on the frequency of these cells. These results suggest that CL CD8(+) T cells are more cytotoxic and may be involved in pathology.
由巴西利什曼原虫引起的皮肤利什曼病（CL）的特征是强烈的Th1反应，可导致皮肤病变发展。在巴西利什曼原虫传播为地方病的地区，高达15%的健康受试者对可溶性利什曼原虫抗原（SLA）的迟发型超敏反应检测呈阳性，被认为患有亚临床（SC）感染。与CL患者相比，SC受试者产生的γ干扰素（IFN-γ）和肿瘤坏死因子α（TNF-α）较少，但他们能够控制感染。本研究的目的是确定CD8(+) T细胞在SC感染和CL中的作用。用SLA刺激外周血单核细胞（PBMC），以确定CD4(+) IFN-γ(+)和CD8(+) IFN-γ(+) T细胞的频率。用巴西利什曼原虫感染PBMC中的单核细胞，并与CD8(+) T细胞共培养，测定被感染单核细胞的频率以及细胞毒性标志物水平、靶细胞凋亡和颗粒酶B。SLA刺激后，SC个体的CD8(+) IFN-γ(+)细胞频率高于CL患者。SC细胞中被感染单核细胞的频率低于CL细胞。CL CD8(+) T细胞比SC CD8(+) T细胞诱导更多被感染单核细胞的凋亡。CL中CD8(+) T细胞的颗粒酶B产生高于SC细胞。虽然使用颗粒酶B抑制剂可减少CL组中的凋亡细胞数量，但使用z-VAD-FMK对这些细胞的频率没有影响。这些结果表明，CL CD8(+) T细胞具有更强的细胞毒性，可能参与了病理过程。
