Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, TX 77555, USA.
World Reference Center for Emerging Viruses and Arboviruses, University of Texas Medical Branch, Galveston, TX 77555, USA.
Viruses. 2024 May 24;16(6):836. doi: 10.3390/v16060836.
The complete lack of yellow fever virus (YFV) in Asia, and the lack of urban YFV transmission in South America, despite the abundance of the peridomestic mosquito vector () is an enigma. An immunologically naïve population of over 2 billion resides in Asia, with most regions infested with the urban YF vector. One hypothesis for the lack of Asian YF, and absence of urban YF in the Americas for over 80 years, is that prior immunity to related flaviviruses like dengue (DENV) or Zika virus (ZIKV) modulates YFV infection and transmission dynamics. Here we utilized an interferon α/β receptor knock-out mouse model to determine the role of pre-existing dengue-2 (DENV-2) and Zika virus (ZIKV) immunity in YF virus infection, and to determine mechanisms of cross-protection. We utilized African and Brazilian YF strains and found that DENV-2 and ZIKV immunity significantly suppresses YFV viremia in mice, but may or may not protect relative to disease outcomes. Cross-protection appears to be mediated mainly by humoral immune responses. These studies underscore the importance of re-assessing the risks associated with YF outbreak while accounting for prior immunity from flaviviruses that are endemic.
亚洲完全没有黄热病病毒（YFV），南美洲也没有城市型 YFV 传播，尽管有大量的半家栖蚊媒介（）存在，这是一个谜。亚洲有超过 20 亿人口，大多数地区都有城市型 YF 媒介的存在，他们对 YFV 没有免疫力。亚洲没有 YF 和美洲 80 多年来没有城市型 YF 的一个假设是，先前对登革热（DENV）或寨卡病毒（ZIKV）等相关黄病毒的免疫可以调节 YFV 感染和传播动力学。在这里，我们利用干扰素 α/β 受体敲除小鼠模型来确定先前存在的登革热 2 型（DENV-2）和寨卡病毒（ZIKV）免疫在 YFV 感染中的作用，并确定交叉保护的机制。我们利用非洲和巴西 YFV 株发现，DENV-2 和 ZIKV 免疫显著抑制小鼠的 YFV 病毒血症，但相对于疾病结果，可能保护也可能不保护。交叉保护似乎主要是通过体液免疫反应介导的。这些研究强调了在考虑到地方性黄病毒先前存在的免疫的情况下，重新评估与 YF 爆发相关的风险的重要性。
