Semeniuk Christina A, McKinnon Lyle, Peters Harold O, Gubbins Michael, Mao Xiaojuan, Ball Terry B, Luo Ma, Plummer Francis A
Department of Medical Microbiology, University of Manitoba, National Microbiology Laboratory, 1015 Arlington Street, Winnipeg, Manitoba R3E 3R2, Canada.
AIDS. 2009 Apr 27;23(7):771-7. doi: 10.1097/QAD.0b013e32832995e0.
The p1 region of HIV-1 gag contains the frameshift stem-loop, gag-pol transframe and a protease cleavage site that are crucial for viral assembly, replication and infectivity. Identifying and characterizing CD8+ epitopes that are under host immune selection in this region will help in designing effective vaccines for HIV-1.
An approach combining bioinformatical analysis and interferon gamma enzyme-linked immunosorbent spot (ELISPOT) assays is used to identify and characterize the epitopes. Potential human leukocyte antigen (HLA)-restricted epitopes were identified by correlating the positively-selected mutations with host HLA alleles.
ELISPOT analysis with overlapping peptides was used to confirm and characterize the epitopes.
Four positively-selected residues were significantly associated with HLA class I alleles, including HLA B1302 (K4R, P = 0.0008 and I5L, P = 0.0108), A7401 (S9N, P = 0.0002) and A*30 genotypes (P7S, P = 0.009), suggesting epitopes restricted by these alleles are present in this region. ELISPOT analysis with patient peripheral blood mononuclear cells (PBMCs) identified seven novel epitopes restricted by the 3 alleles. Two types of epitopes were observed in this region based on the ELISPOT responses, Type I: the positively-selected variation does not affect CD8+ T-cell responses; and Type II: the CD8+ T-cell responses are determined by the epitope variants.
We identified and characterized seven novel CD8+ epitopes in the p1 spacer protein region. Classifying the effects of positively-selected variants on CD8+ T-cell responses will help in designing effective vaccines for HIV-1.
HIV-1 gag的p1区域包含移码茎环、gag-pol跨框结构和一个蛋白酶切割位点，这些对于病毒组装、复制和感染性至关重要。鉴定和表征该区域中受到宿主免疫选择的CD8 +表位将有助于设计针对HIV-1的有效疫苗。
采用生物信息学分析与干扰素γ酶联免疫斑点（ELISPOT）测定相结合的方法来鉴定和表征表位。通过将正选择突变与宿主HLA等位基因相关联，鉴定潜在的人类白细胞抗原（HLA）限制性表位。
使用重叠肽进行ELISPOT分析以确认和表征表位。
四个正选择的残基与HLA I类等位基因显著相关，包括HLA B1302（K4R，P = 0.0008和I5L，P = 0.0108）、A7401（S9N，P = 0.0002）和A*30基因型（P7S，P = 0.009），表明受这些等位基因限制的表位存在于该区域。对患者外周血单核细胞（PBMC）进行的ELISPOT分析鉴定出7个受这3个等位基因限制的新表位。基于ELISPOT反应，在该区域观察到两种类型的表位，I型：正选择的变异不影响CD8 + T细胞反应；II型：CD8 + T细胞反应由表位变异体决定。
我们在p1间隔蛋白区域鉴定并表征了7个新的CD8 +表位。对正选择变异体对CD8 + T细胞反应的影响进行分类将有助于设计针对HIV-1的有效疫苗。
