Silva Bosco Christiano Maciel da, Grassi Maria Fernanda Rios, Coutinho Raimundo, Mascarenhas Rita Elizabeth Moreira, Olavarria Viviana Nilla, Coutinho-Borgo Adriana, Kalil Jorge, Cunha Neto Edecio, Fonseca Simone Gonçalves
Laboratório de Imunologia, Instituto do Coração, São Paulo, SP, Brasil.
Laboratório Avançado de Saúde Pública, Fundação Oswaldo Cruz, Salvador, BA, Brasil.
Mem Inst Oswaldo Cruz. 2014 Dec;109(8):999-1004. doi: 10.1590/0074-0276140193. Epub 2014 Dec 9.
The interferon (IFN)-γ response to peptides can be a useful diagnostic marker of Mycobacterium tuberculosis (MTB) latent infection. We identified promiscuous and potentially protective CD4+ T-cell epitopes from the most conserved regions of MTB antigenic proteins by scanning the MTB antigenic proteins GroEL2, phosphate-binding protein 1 precursor and 19 kDa antigen with the TEPITOPE algorithm. Seven peptide sequences predicted to bind to multiple human leukocyte antigen (HLA)-DR molecules were synthesised and tested with IFN-γ enzyme-linked immunospot (ELISPOT) assays using peripheral blood mononuclear cells (PBMCs) from 16 Mantoux tuberculin skin test (TST)-positive and 16 TST-negative healthy donors. Eighty-eight percent of TST-positive donors responded to at least one of the peptides, compared to 25% of TST-negative donors. Each individual peptide induced IFN-γ production by PBMCs from at least 31% of the TST-positive donors. The magnitude of the response against all peptides was 182 ± 230 x 106 IFN-γ spot forming cells (SFC) among TST-positive donors and 36 ± 62 x 106 SFC among TST-negative donors (p = 0.007). The response to GroEL2 (463-477) was only observed in the TST-positive group. This combination of novel MTB CD4 T-cell epitopes should be tested in a larger cohort of individuals with latent tuberculosis (TB) to evaluate its potential to diagnose latent TB and it may be included in ELISPOT-based IFN-γ assays to identify individuals with this condition.
干扰素（IFN）-γ对肽段的反应可能是结核分枝杆菌（MTB）潜伏感染的一种有用诊断标志物。我们通过用TEPITOPE算法扫描MTB抗原蛋白GroEL2、磷酸结合蛋白1前体和19 kDa抗原，从MTB抗原蛋白最保守区域鉴定出混杂且可能具有保护性的CD4 + T细胞表位。合成了7个预测可与多种人类白细胞抗原（HLA）-DR分子结合的肽序列，并使用来自16名结核菌素皮肤试验（TST）阳性和16名TST阴性健康供者的外周血单个核细胞（PBMC），通过IFN-γ酶联免疫斑点（ELISPOT）试验进行检测。88%的TST阳性供者对至少一种肽有反应，而TST阴性供者的这一比例为25%。每个单独的肽至少能诱导31%的TST阳性供者的PBMC产生IFN-γ。TST阳性供者中针对所有肽的反应强度为182±230×10⁶ IFN-γ斑点形成细胞（SFC），TST阴性供者中为36±62×10⁶ SFC（p = 0.007）。仅在TST阳性组中观察到对GroEL2（463 - 477）的反应。这种新型MTB CD4 T细胞表位组合应在更大的潜伏性结核病患者队列中进行测试，以评估其诊断潜伏性结核病的潜力，并且它可能被纳入基于ELISPOT的IFN-γ检测中，以识别患有这种疾病的个体。
