Liao Hua, Franck Emilie, Fréret Manuel, Adriouch Sahil, Baba-Amer Yasmine, Authier Francois-Jerome, Boyer Olivier, Gherardi Romain K
INSERM U955, E10, Université Paris-Est, Créteil, France.
Arthritis Rheum. 2012 Oct;64(10):3441-51. doi: 10.1002/art.34551.
To investigate the influence of myoinjury on antigen presentation to T cells in draining lymph nodes (LNs).
Muscle crush was performed in mice injected with exogenous ovalbumin (OVA) and in transgenic SM-OVA mice expressing OVA as a muscle-specific self antigen. Antigen exposure and the resulting stimulation of T cell proliferation in draining LNs was assessed by transferring carboxyfluorescein succinimidyl ester (CFSE)-labeled OVA-specific CD8+ and CD4+ T cells from OT-I and OT-II mice and by measuring the dilution of CFSE, which directly reflects their proliferation. The role of monocyte-derived dendritic cells (DCs) in T cell priming was assessed using pharmacologic blockade of DC migration. Immunofluorescence was used to detect CD8+ T cells, inflammatory monocyte-derived DCs, and type I major histocompatibility complex (MHC)-expressing myofibers in crushed muscle, and to assess expression of perforin, interferon-γ (IFNγ), interleukin-2 (IL-2), IL-10, and transforming growth factor β1 (TGFβ1).
OVA injection into intact muscle induced strong proliferation of CD4+ and CD8+ T cells, indicating efficient exposure of soluble antigens in draining LNs. OVA-specific CD8+ T cell proliferation in draining LNs of SM-OVA mice required myoinjury and was unaffected by pharmacologic inhibition of monocyte-derived DC migration. On day 7 postinjury, activated CD8+ T cells expressing perforin, IFNγ and IL-2 were transiently detected in crushed muscle, and these cells were in close contact with class I MHC-positive regenerating myofibers. Beginning on day 7, the immunosuppressive cytokines IL-10 and TGFβ1 were conspicuously expressed by CD11b+ cells, and CD8+ T cells rapidly disappeared from the healing muscle.
Myofiber damage induces an episode of muscle antigen-specific CD8+ T cell proliferation in draining LNs. Activated CD8+ T cells transiently infiltrate the injured muscle, with prompt control by immunosuppressive cues. Inadequate control might favor sustained autoimmune myositis.
研究肌损伤对引流淋巴结（LN）中抗原呈递给T细胞的影响。
对注射外源性卵清蛋白（OVA）的小鼠以及表达OVA作为肌肉特异性自身抗原的转基因SM-OVA小鼠进行肌肉挤压。通过转移来自OT-I和OT-II小鼠的羧基荧光素琥珀酰亚胺酯（CFSE）标记的OVA特异性CD8⁺和CD4⁺T细胞，并测量CFSE的稀释度来评估引流淋巴结中抗原暴露及由此产生的T细胞增殖刺激，CFSE稀释度直接反映其增殖情况。使用药物阻断DC迁移来评估单核细胞衍生的树突状细胞（DC）在T细胞致敏中的作用。采用免疫荧光法检测挤压肌肉中的CD8⁺T细胞、炎性单核细胞衍生的DC以及表达I类主要组织相容性复合体（MHC）的肌纤维，并评估穿孔素、干扰素-γ（IFNγ）、白细胞介素-2（IL-2）、IL-10和转化生长因子β1（TGFβ1）的表达。
将OVA注射到完整肌肉中可诱导CD4⁺和CD8⁺T细胞强烈增殖，表明引流淋巴结中可溶性抗原有效暴露。SM-OVA小鼠引流淋巴结中OVA特异性CD8⁺T细胞增殖需要肌损伤，且不受单核细胞衍生DC迁移的药物抑制影响。损伤后第7天，在挤压肌肉中短暂检测到表达穿孔素、IFNγ和IL-2的活化CD8⁺T细胞，这些细胞与I类MHC阳性的再生肌纤维紧密接触。从第7天开始，免疫抑制细胞因子IL-10和TGFβ1由CD11b⁺细胞显著表达，且CD8⁺T细胞迅速从愈合的肌肉中消失。
肌纤维损伤在引流淋巴结中诱导了一段肌肉抗原特异性CD8⁺T细胞增殖期。活化的CD8⁺T细胞短暂浸润受损肌肉，并迅速受到免疫抑制信号的控制。控制不足可能有利于持续性自身免疫性肌炎。
