Hoarau Jean-Jacques, Gay Frederick, Pellé Olivier, Samri Assia, Jaffar-Bandjee Marie-Christine, Gasque Philippe, Autran Brigitte
Immunopathology and infectious diseases research grouping, GRI/IRG EA4517, University of La Reunion and Centre Hospitalier Universitaire (CHU North Felix-Guyon), Saint-Denis, Louisiana, United States of America Reunion - France.
Department of Medical Biology, Parasitology, Pitié-Salpêtrière Hospital, Pierre and Marie Curie University, Paris, France.
PLoS One. 2013 Dec 23;8(12):e84695. doi: 10.1371/journal.pone.0084695. eCollection 2013.
To characterize the immunity developed by patients infected by chikungunya virus (CHIKV), we studied the intensity and specificity of CHIKV-specific T cells mediated responses in chronic and recovered patients at 12 to 24 months post-infection. T cells were challenged in vitro against CHIKV synthetic peptides covering the length of three viral proteins, capsid, E2 and nsP1 proteins as well as all inactivated virus particles. Cytokine production was assessed by ELISPOT and intracellular labeling. T cells producing IFN-γ were detected against CHIKV in 85% patient's cells either by direct ELISPOT assay (69% of patients) or after expansion of memory T cells allowing the detection of both CD4 and CD8 specific-T cells in 16% additional cases. The IFN-γ response was mainly engaged in response to nsP1 or E2 (52% and 46% cases, respectively) but in only 27% cases against the capsid. The anti-E2 response represented half the magnitude of the total CHIKV IFN-γ production and was mainly directed against the C-terminal half part of the protein. Almost all patients had conserved a T cell specific response against CHIKV with a clear hierarchy of T cell responses (CD8 > CD4) engaged against E2 > nsP1 > capsid. More importantly, the intensity of responses was not significantly different between recovered and chronic patients. These findings constitute key elements to a better understanding of patient T cell immunoreactivity against CHIKV and argue against a possible defect of T cell immunoresponse in the chronicity post-CHIKV infection.
为了描述感染基孔肯雅病毒（CHIKV）的患者所产生的免疫力，我们研究了感染后12至24个月的慢性患者和康复患者中CHIKV特异性T细胞介导反应的强度和特异性。体外使用覆盖三种病毒蛋白（衣壳蛋白、E2蛋白和nsP1蛋白）全长的CHIKV合成肽以及所有灭活病毒颗粒对T细胞进行刺激。通过ELISPOT和细胞内标记评估细胞因子的产生。通过直接ELISPOT测定法（69%的患者）或在记忆T细胞扩增后，在另外16%的病例中检测到产生IFN-γ的T细胞，从而在85%患者的细胞中检测到针对CHIKV的T细胞。IFN-γ反应主要针对nsP1或E2（分别为52%和46%的病例），但仅27%的病例针对衣壳蛋白。抗E2反应占CHIKV总IFN-γ产生量的一半，并且主要针对该蛋白的C端后半部分。几乎所有患者都保留了针对CHIKV的T细胞特异性反应，针对E2>nsP1>衣壳蛋白的T细胞反应具有明确的层次结构（CD8>CD4）。更重要的是，康复患者和慢性患者之间的反应强度没有显著差异。这些发现是更好地理解患者针对CHIKV的T细胞免疫反应的关键因素，并反驳了CHIKV感染后慢性期T细胞免疫反应可能存在缺陷的观点。
