Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia.
Viral Vaccine Discovery and Early Development, Janssen Vaccines and Prevention BV, Leiden, The Netherlands.
Microbiol Spectr. 2022 Aug 31;10(4):e0109722. doi: 10.1128/spectrum.01097-22. Epub 2022 Aug 4.
Human adenovirus type 26 (HAdV26) has been recognized as a promising platform for vaccine vector development, and very recently vaccine against COVID-19 based on HAdV26 was authorized for emergency use. Nevertheless, basic biology of this virus, namely, pathway which HAdV26 uses to enter the cell, is still insufficiently known. We have shown here that HAdV26 infection of human epithelial cells expressing low amount of αvβ3 integrin involves clathrin and is caveolin-1-independent, while HAdV26 infection of cells with high amount of αvβ3 integrin does not involve clathrin but is caveolin-1-dependent. Thus, this study demonstrates that caveolin-1 is limiting factor in αvβ3 integrin-mediated HAdV26 infection. Regardless of αvβ3 integrin expression, HAdV26 infection involves dynamin-2. Our data provide for the first-time description of HAdV26 cell entry pathway, hence increase our knowledge of HAdV26 infection. Knowing that functionality of adenovirus vector is influenced by its cell entry pathway and intracellular trafficking, our results will contribute to better understanding of HAdV26 immunogenicity and antigen presentation when used as vaccine vector. In order to fulfill its role as a vector, adenovirus needs to successfully deliver its DNA genome to the host nucleus, a process highly influenced by adenovirus intracellular translocation. Thus, cell entry pathway and intracellular trafficking determine functionality of human adenovirus-based vectors. Endocytosis of HAdV26, currently extensively studied as a vaccine vector, has not been described so far. We present here that HAdV26 infection of human epithelial cells with high expression of αvβ3 integrin, one of the putative HAdV26 receptors, is caveolin-1- and partially dynamin-2-dependent. Since caveolin containing domains provide a unique environment for specific signaling events and participate in inflammatory signaling one can imagine that directing HAdV26 cell entry toward caveolin-1-mediate pathway might play role in immunogenicity of this virus. Therefore, our results contribute to better understanding of HAdV26 infection pathway, hence, can be helpful in explaining induction of immune response and antigen presentation by HAdV26-based vaccine vector.
人腺病毒 26 型（HAdV26）已被认为是疫苗载体开发的有前途的平台，最近基于 HAdV26 的 COVID-19 疫苗已被授权紧急使用。然而，该病毒的基本生物学，即 HAdV26 进入细胞的途径，仍然知之甚少。我们在这里表明，低水平表达αvβ3 整联蛋白的人上皮细胞感染 HAdV26 涉及网格蛋白，并且不依赖于窖蛋白 1，而高水平表达αvβ3 整联蛋白的细胞感染 HAdV26 不涉及网格蛋白，但依赖于窖蛋白 1。因此，本研究表明窖蛋白 1 是αvβ3 整联蛋白介导的 HAdV26 感染的限制因素。无论αvβ3 整联蛋白表达如何，HAdV26 感染都涉及 dynamin-2。我们的数据首次描述了 HAdV26 细胞进入途径，从而增加了我们对 HAdV26 感染的认识。由于腺病毒载体的功能受其细胞进入途径和细胞内运输的影响，我们的结果将有助于更好地理解 HAdV26 作为疫苗载体的免疫原性和抗原呈递。为了发挥载体的作用，腺病毒需要将其 DNA 基因组成功递送到宿主细胞核，这一过程高度依赖于腺病毒的细胞内转运。因此，细胞进入途径和细胞内运输决定了基于人腺病毒的载体的功能。目前作为疫苗载体广泛研究的 HAdV26 的内吞作用尚未得到描述。我们在这里提出，高表达αvβ3 整联蛋白的人上皮细胞感染 HAdV26，是 HAdV26 的一种假定受体，依赖于窖蛋白 1，部分依赖于 dynamin-2。由于含有窖蛋白的结构域为特定的信号事件提供了独特的环境，并参与炎症信号，因此可以想象，将 HAdV26 细胞进入途径指向窖蛋白 1 介导的途径可能在该病毒的免疫原性中发挥作用。因此，我们的研究结果有助于更好地理解 HAdV26 感染途径，从而有助于解释基于 HAdV26 的疫苗载体诱导免疫反应和抗原呈递的机制。
