Favaroni Alison, Trinks Alexander, Weber Michael, Hegemann Johannes H, Schnee Christiane
Institute of Molecular Pathogenesis, Friedrich-Loeffler-Institut, Jena, Germany.
Institute of Functional Microbial Genomics, Heinrich Heine University Duesseldorf, Duesseldorf, Germany.
Front Microbiol. 2021 Mar 29;12:656209. doi: 10.3389/fmicb.2021.656209. eCollection 2021.
is the etiological agent of chlamydiosis in birds and can be transmitted to humans, causing severe systemic disease. infects a broad range of hosts; strains are isolated not only from birds but also from mammals, where they seem to have a reduced infectious and zoonotic potential. Comparative analysis of chlamydial genomes revealed the coding sequences of polymorphic membrane proteins (Pmps) to be highly variable regions. Pmps are characterized as adhesins in and and are immunoreactive proteins in several species. Thus, Pmps are considered to be associated with tissue tropism and pathogenicity. harbors 21 Pmps. We hypothesize that the different infectious potential and host tropism of avian and mammalian strains is dependent on differences in their Pmp repertoires. In this study, we experimentally confirmed the different virulence of avian and mammalian strains, by testing the survival rate of infected embryonated eggs and chlamydiae dissemination in the embryos. Further, we investigated the possible involvement of Pmps in host tropism. Analysis of sequences from 10 strains confirmed a high degree of variation, but no correlation with host tropism was identified. However, comparison of Pmp expression profiles from different strains showed that Pmps of the G group are the most variably expressed, also among avian and mammalian strains. To investigate their functions, selected Pmps were recombinantly produced from one avian and one mammalian representative strain and their adhesion abilities and relevance for the infection of strains in avian and mammalian cells were tested. For the first time, we identified Pmp22D, Pmp8G, and OmcB as relevant adhesins, essential during infection of strains in general. Moreover, we propose Pmp17G as a possible key player for host adaptation, as it could only bind to and influence the infection in avian cells, but it had no relevant impact towards infection in mammalian cells. These data support the hypothesis that distinct Pmp repertoires in combination with specific host factors may contribute to host tropism of strains.
是鸟类衣原体病的病原体，可传播给人类，引发严重的全身性疾病。它感染广泛的宿主；不仅从鸟类中分离出菌株，还从哺乳动物中分离出，在哺乳动物中它们的感染性和人畜共患病潜力似乎有所降低。衣原体基因组的比较分析表明，多态性膜蛋白（Pmps）的编码序列是高度可变区域。Pmps在[具体物种1]和[具体物种2]中被表征为黏附素，在几个[衣原体相关物种]中是免疫反应性蛋白。因此，Pmps被认为与组织嗜性和致病性有关。[衣原体名称]含有21种Pmps。我们假设禽源和哺乳动物源[衣原体名称]菌株不同的感染潜力和宿主嗜性取决于它们Pmp库的差异。在本研究中，我们通过测试感染的胚胎蛋的存活率和衣原体在胚胎中的传播，实验证实了禽源和哺乳动物源菌株的不同毒力。此外，我们研究了Pmps在宿主嗜性中的可能作用。对来自10个[衣原体名称]菌株的序列分析证实了高度的变异性，但未发现与宿主嗜性相关。然而，不同菌株Pmp表达谱的比较表明，G组的Pmps在禽源和哺乳动物源菌株中也是表达变化最大可变的。为了研究它们的功能，从一个禽源和一个哺乳动物源代表性菌株中重组产生了选定的Pmps，并测试了它们的黏附能力以及对[衣原体名称]菌株在禽源和哺乳动物细胞中感染的相关性。我们首次确定Pmp22D、Pmp8G和OmcB是一般在[衣原体名称]菌株感染期间必不可少的相关黏附素。此外，我们提出Pmp17G可能是宿主适应性的关键因素，因为它只能结合并影响在禽源细胞中的感染，但对在哺乳动物细胞中的感染没有相关影响。这些数据支持了这样的假设，即不同的Pmp库与特定的宿主因素相结合可能有助于[衣原体名称]菌株的宿主嗜性。
