Infectious Diseases Unit-HIVACAT, Hospital Clínic, Barcelona, Spain.
Vaccine. 2011 Jul 18;29(32):5250-9. doi: 10.1016/j.vaccine.2011.05.016. Epub 2011 May 24.
Cell-to-cell HIV spread through virological synapses proceeds in two steps, first HIV particles are rapidly transferred to target cells in a CD4-dependent manner and then coreceptor-dependent events allow for infection or death of single target cells and cell-to-cell fusion.
293T or MOLT cells producing HIV particles were cocultured with primary CD4 T-cells or reporter cell lines. The extent of HIV transfer, cell fusion and target cell death was assessed. Inhibition by sera from 19 HIV-infected patients was evaluated and compared with cell-free HIV neutralization using different envelopes from clades A, B, C and E.
Sera showed different abilities to protect CD4 T-cells from cell-to-cell transfer, fusion or death when cocultured with HIV producing 293T cells. Some sera were able to block all parameters (a property of IgGb12), while other showed lower activity against HIV transfer despite being able to block fusion and death (a property of antibodies blocking post-CD4 binding steps). Neutralization of cell-to-cell HIV transfer strongly correlated with IgG binding to native Env. Interestingly, sera that efficiently blocked HIV transfer showed broader neutralizing response, as they neutralized a higher percentage of the viruses tested compared with sera showing low CD4 binding site responses (P=0.01). Similar results were observed in a model of T cell-T cell HIV transmission, although this experimental model showed lower capacity to discriminate broadly neutralizing responses.
Cell-to-cell HIV transfer assays identify sera with broadly neutralizing capacity and may help to characterize anti-HIV humoral responses.
通过病毒学突触的细胞间 HIV 传播分两步进行，首先 HIV 颗粒以 CD4 依赖性的方式迅速转移到靶细胞，然后核心受体依赖性事件允许单个靶细胞感染或死亡以及细胞间融合。
产生 HIV 颗粒的 293T 或 MOLT 细胞与原代 CD4 T 细胞或报告细胞系共培养。评估 HIV 转移、细胞融合和靶细胞死亡的程度。评估来自 19 名 HIV 感染患者的血清的抑制作用，并与使用来自 A、B、C 和 E 群的不同包膜的无细胞 HIV 中和进行比较。
当与产生 293T 细胞的 HIV 共培养时，血清显示出不同的能力来保护 CD4 T 细胞免受细胞间转移、融合或死亡。一些血清能够阻断所有参数（IgGb12 的特性），而其他血清尽管能够阻断融合和死亡，但对 HIV 转移的活性较低（阻断 CD4 结合后步骤的抗体的特性）。细胞间 HIV 转移的中和与 IgG 与天然 Env 的结合强烈相关。有趣的是，能够有效阻断 HIV 转移的血清显示出更广泛的中和反应，因为与显示低 CD4 结合位点反应的血清相比，它们能够中和更高比例的测试病毒（P=0.01）。在 T 细胞-T 细胞 HIV 传播模型中观察到类似的结果，尽管该实验模型显示出较低的区分广泛中和反应的能力。
细胞间 HIV 转移测定法可识别具有广泛中和能力的血清，并可能有助于表征抗 HIV 体液反应。
