Role of the surface glycoproteins of a bat-derived mumps virus concerning viral entry, replication, tropism, and virulence

众所周知，蝙蝠是多种病毒的宿主。近年来，在蝙蝠中发现了副粘病毒科的成员。蝙蝠衍生副粘病毒的一个众所周知的例子是人畜共患的亨尼帕病毒、尼帕病毒和亨德拉病毒，它们的宿主是狐蝠。此外，在蝙蝠中还检出了风疹病毒和麻疹病毒属的成员。在蝙蝠中检测病毒核酸和/或中和副粘病毒抗体的尝试已经相当成功；然而，从蝙蝠中分离传染性病毒仍然是一项具有挑战性的任务。只要只有病毒序列而没有病毒分离物可用，就不可能评估人畜共患的潜在风险。蝙蝠源性腮腺炎病毒（batMuV）是风疹病毒属的一个成员；在非洲狐蝠身上发现了它的RNA基因组。这种病毒特别令人感兴趣，因为它的基因组组织与人类腮腺炎病毒（MuV）的基因组组织相同。此外，与人类MuV菌株相比，其每个蛋白质的氨基酸序列高度保守。鉴于没有传染性的蝙蝠muv分离物可用，表面糖蛋白，融合(F)和血凝素-神经氨酸酶（HN）蛋白，在细胞培养系统中表达，并用于首次分析其功能特征。通过对不同哺乳动物细胞系的多核巨细胞的检测，证实了batMuV糖蛋白的功能活性。本项目的目的是分析病毒表面糖蛋白在病毒进入、趋向性、复制和毒力方面的作用。因此，将产生重组MuV，将人MuV分离物的F和HN蛋白替换为蝙蝠MuV的相应糖蛋白，并进一步用于永活细胞系的感染。我们将感染与蝙蝠muv宿主物种同属一科的翼手动物细胞，以及不同的哺乳动物细胞系，以回答重组病毒在翼手动物和非翼手动物细胞之间复制是否不同的问题。此外，感染研究将提供关于病毒进入的不同关键因素的新信息，例如病毒颗粒与细胞受体的结合。将表达蝙蝠MuV糖蛋白的重组病毒的结果与仅含有人蛋白的重组MuV的结果进行比较。我们的研究结果将为了解蝙蝠muv的复制周期和分析这些蝙蝠病毒的人畜共患潜力提供基础。

Bats are known to be the reservoir of a variety of viruses. In recent years, especially members of the Paramyxoviridae family have been detected in bats. One well-known example for bat-derived paramyxoviruses are the zoonotic henipaviruses Nipah- and Hendravirus, which have their reservoir host in flying foxes. Besides, also members of the genera Rubulavirus and Morbillivirus were detected in bats. Attempts to detect viral nucleic acid and/or neutralizing antibodies against paramyxoviruses in bats have been quite successful; however, the isolation of infectious viruses from bats is still a challenging task. As long as only viral sequences but no virus isolate are available, it is not possible to evaluate the risk of a zoonotic potential.The bat-derived mumps virus (batMuV) is a member of the genus Rubulavirus; its RNA genome has been detected in African flying foxes. This virus is of particular interest, becausethe viral genome organization is identical to that of human mumps viruses (MuV). Furthermore, the amino acid sequences of each of its protein are highly conserved in comparison to human MuV strains. Given that no infectious batMuV isolate is available, the surface glycoproteins, the fusion (F) and the hemagglutinin-neuraminidase (HN) protein, were expressed in cell culture systems and used for a first analysis of their functional characteristics. The functional activity of the batMuV glycoproteins was demonstrated by the detection of multinucleated giant cells in different mammalian cell lines.Aim of this project is to analyze the role of the viral surface glycoproteins concerning virus entry, tropism, replication, and virulence. Therefore, recombinant MuV, in which the F and HN protein of a human MuV isolate are replaced by the corresponding glycoproteins of batMuV, will be generated and further used for the infection of immortalized cell lines. We are going to infect chiropteran cells, which belong to the same family as the host species of batMuV, as well as different mammalian cell lines, to answer the question if the replication of recombinant viruses differs between chiropteran and non-chiropteran cells. Further, the infection studies will provide new information about different key factors, which play an important role for the virus entry, such as the binding of viral particles to cellular receptors. The results, obtained for recombinant viruses which express the batMuV glycoproteins, will be compared to those obtained for recombinant MuV which contain only human proteins. Our results will provide a basis to understand the replication cycle of batMuV and enable the analysis of the zoonotic potential of these bat viruses.