Department of Microbiology and Immunology, School of Medicine, University of North Carolina at Chapel Hillgrid.10698.36, Chapel Hill, North Carolina, USA.
Center for AIDS Research, School of Medicine, University of North Carolina at Chapel Hillgrid.10698.36, Chapel Hill, North Carolina, USA.
mSphere. 2022 Feb 23;7(1):e0083921. doi: 10.1128/msphere.00839-21.
Improved access to antiretroviral therapy (ART) and antenatal care has significantly reduced and peripartum mother-to-child human immunodeficiency virus (HIV) transmission. However, as breast milk transmission of HIV still occurs at an unacceptable rate, there remains a need to develop an effective vaccine for the pediatric population. Previously, we compared different HIV vaccine strategies, intervals, and adjuvants in infant rhesus macaques to optimize the induction of HIV envelope (Env)-specific antibodies with Fc-mediated effector function. In this study, we tested the efficacy of an optimized vaccine regimen against oral simian-human immunodeficiency virus (SHIV) acquisition in infant macaques. Twelve animals were immunized with 1086.c gp120 protein adjuvanted with 3M-052 in stable emulsion and modified vaccinia Ankara (MVA) virus expressing 1086.c HIV Env. Twelve control animals were immunized with empty MVA. The vaccine prime was given within 10 days of birth, with booster doses being administered at weeks 6 and 12. The vaccine regimen induced Env-specific plasma IgG antibodies capable of antibody-dependent cellular cytotoxicity (ADCC) and phagocytosis (ADCP). Beginning at week 15, infants were exposed orally to escalating doses of heterologous SHIV-1157(QNE)Y173H once a week until infected. Despite the induction of strong Fc-mediated antibody responses, the vaccine regimen did not reduce the risk of infection or time to acquisition compared to controls. However, among vaccinated animals, ADCC postvaccination and postinfection was associated with reduced peak viremia. Thus, nonneutralizing Env-specific antibodies with Fc effector function elicited by this vaccine regimen were insufficient for protection against heterologous oral SHIV infection shortly after the final immunization but may have contributed to control of viremia. Women of childbearing age are three times more likely to contract HIV infection than their male counterparts. Poor HIV testing rates coupled with low adherence to antiretroviral therapy (ART) result in a high risk of mother-to-infant HIV transmission, especially during the breastfeeding period. A preventative vaccine could curb pediatric HIV infections, reduce potential health sequalae, and prevent the need for lifelong ART in this population. The results of the current study imply that the HIV Env-specific IgG antibodies elicited by this candidate vaccine regimen, despite a high magnitude of Fc-mediated effector function but a lack of neutralizing antibodies and polyfunctional T cell responses, were insufficient to protect infant rhesus macaques against oral virus acquisition.
抗逆转录病毒疗法(ART)和产前护理的可及性提高显著降低了围产期母婴传播的人类免疫缺陷病毒(HIV)。然而,由于母乳传播 HIV 的比例仍然高得不可接受,因此仍需要为儿科人群开发有效的疫苗。此前,我们比较了不同的 HIV 疫苗策略、间隔和佐剂在恒河猴婴儿中的效果,以优化具有 Fc 介导的效应功能的 HIV 包膜(Env)特异性抗体的诱导。在这项研究中,我们测试了优化疫苗方案对婴儿恒河猴口服感染猴免疫缺陷病毒(SHIV)的效果。12 只动物用 1086.c gp120 蛋白和 3M-052 佐剂稳定乳液及表达 1086.c HIV Env 的改良痘苗病毒 Ankara(MVA)病毒免疫。12 只对照动物用空 MVA 免疫。疫苗初免在出生后 10 天内进行,在第 6 周和第 12 周进行加强免疫。疫苗方案诱导了能够进行抗体依赖细胞毒性(ADCC)和吞噬作用(ADCP)的 Env 特异性血浆 IgG 抗体。从第 15 周开始,婴儿每周一次口服接受递增剂量的异源 SHIV-1157(QNE)Y173H,直到感染。尽管诱导了强烈的 Fc 介导的抗体反应,但与对照组相比,疫苗方案并未降低感染风险或感染时间。然而,在接种疫苗的动物中,接种后和感染后的 ADCC 与降低峰值病毒血症相关。因此,该疫苗方案诱导的具有 Fc 效应功能的非中和性 Env 特异性抗体不足以在最后一次免疫后不久预防异源口服 SHIV 感染,但可能有助于控制病毒血症。生育年龄的妇女感染 HIV 的风险比男性高三倍。HIV 检测率低,抗逆转录病毒治疗(ART)依从性低,导致母婴 HIV 传播风险高,尤其是在哺乳期。预防性疫苗可以遏制儿科 HIV 感染,减少潜在的健康后果,并防止该人群需要终生接受 ART。目前研究的结果表明,尽管候选疫苗方案诱导的 HIV Env 特异性 IgG 抗体具有高 Fc 介导的效应功能,但缺乏中和抗体和多能 T 细胞反应,不足以保护婴儿恒河猴免受口服病毒感染。
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