Vaccine Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, United States.
Vaccine. 2011 Apr 12;29(17):3310-9. doi: 10.1016/j.vaccine.2011.02.066. Epub 2011 Mar 5.
An effective HIV vaccine requires strong systemic and mucosal, cellular and humoral immunity. Numerous non-human primate studies have investigated memory T cells, but not memory B cells. Humoral immunologic memory is mediated by long-lived antibody-secreting plasma cells and differentiation of memory B cells into short-lived plasma blasts following re-exposure to immunizing antigen. Here we studied memory B cells in vaccinated rhesus macaques. PBMC were stimulated polyclonally using CD40 Ligand, IL-21 and CpG to induce B cell proliferation and differentiation into antibody secreting cells (ASCs). Flow cytometry was used for phenotyping and evaluating proliferation by CFSE dilution. B cell responses were quantified by ELISPOT. Methodology was established using PBMC of vaccinated elite-controller macaques that exhibited strong, multi-functional antibody activities. Subsequently, memory B cells elicited by two replicating Ad-recombinant prime/envelope boost regimens were retrospectively evaluated pre- and post-SIV and SHIV challenges. The vaccine regimens induced SIV and HIV Env-specific IgG and IgA memory B cells. Prior to challenge, IgA memory B cells were more numerous than IgG memory B cells, reflecting the mucosal priming immunizations. Pre- and post-challenge memory B cells were correlated with functional antibody responses including antibody-dependent cellular cytotoxicity (ADCC), antibody-dependent cell-mediated viral inhibition (ADCVI) and transcytosis inhibition. Post-challenge, Env-specific IgG and IgA memory B cells were correlated with reduced chronic viremia. We conclude that functional antibody responses elicited by our prime/boost regimen were effectively incorporated into the memory B cell pool where they contributed to control of viremia following re-exposure to the immunizing antigen.
一种有效的 HIV 疫苗需要强大的系统性和黏膜性、细胞性和体液性免疫。许多非人类灵长类动物研究都调查了记忆 T 细胞，但没有调查记忆 B 细胞。体液免疫记忆是由长寿的抗体分泌浆细胞介导的，并且在再次暴露于免疫原性抗原后，记忆 B 细胞分化为短命的浆母细胞。在这里，我们研究了接种疫苗的恒河猴中的记忆 B 细胞。使用 CD40 配体、IL-21 和 CpG 多克隆刺激 PBMC，以诱导 B 细胞增殖并分化为分泌抗体的细胞 (ASCs)。流式细胞术用于表型分析和通过 CFSE 稀释评估增殖。通过 ELISPOT 定量 B 细胞反应。使用表现出强大、多功能抗体活性的接种精英控制猕猴的 PBMC 建立了方法。随后，回顾性评估了两种复制型 Ad-重组疫苗初免/包膜加强方案引起的记忆 B 细胞，评估时间为 SIV 和 SHIV 感染前和感染后。疫苗方案诱导了 SIV 和 HIV Env 特异性 IgG 和 IgA 记忆 B 细胞。在挑战之前，IgA 记忆 B 细胞比 IgG 记忆 B 细胞更多，反映了黏膜初级免疫接种。在挑战前和后，记忆 B 细胞与功能性抗体反应相关，包括抗体依赖性细胞毒性 (ADCC)、抗体依赖性细胞介导的病毒抑制 (ADCVI) 和转胞吞抑制。在挑战后，Env 特异性 IgG 和 IgA 记忆 B 细胞与慢性病毒血症减少相关。我们得出结论，我们的初免/加强方案引起的功能性抗体反应有效地被纳入记忆 B 细胞池，在再次暴露于免疫原性抗原时有助于控制病毒血症。
