Marburg and Ebola virus infections elicit a complex, muted inflammatory state in bats

  1. Anitha D. Jayaprakash
  2. Adam J. Ronk
  3. Abhishek N. Prasad
  4. Michael F. Covington
  5. Kathryn R. Stein
  6. Toni M. Schwarz
  7. Saboor Hekmaty
  8. Karla A. Fenton
  9. Thomas W. Geisbert
  10. Christopher F. Basler
  11. Alexander Bukreyev
  12. Ravi Sachidanandam

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Abstract

The Marburg and Ebola filoviruses cause a severe, often fatal, disease in humans and nonhuman primates but have only subclinical effects in bats, including Egyptian rousettes, which are a natural reservoir of Marburg virus. A fundamental question is why these viruses are highly pathogenic in humans but fail to cause disease in bats. To understand how bats resist the disease caused by filoviruses, we infected one cohort of Egyptian rousette bats with Marburg virus and another cohort with Ebola virus and harvested multiple tissues for mRNA expression analysis. While virus transcripts were found primarily in the liver, Principal component analysis (PCA) revealed coordinated changes across multiple tissues. Gene signatures in kidney and liver pointed at induction of vasodilation, reduction of coagulation and changes in the regulation of iron metabolism. Signatures of immune response detected in spleen and liver indicated a robust anti-inflammatory state signified by macrophages in the M2 state and an active T cell response. Many of the responsive genes were found to be evolutionarily divergent, providing a framework for understanding the differences in outcomes of filovirus infections between bats and humans. In this study, we outline multiple interconnected pathways that respond to infection by MARV and EBOV, providing insights into the complexity of the mechanisms that enable bats to resist the disease caused by filoviral infections. The results have the potential to aid in the development of new strategies to effectively mitigate and treat the disease caused by these viruses in humans.

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  1. Review Commons

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    Reply to the reviewers

    Reviewer #1

    The first hypothesis of the manuscript is that, rather than a change in a single immune pathway being responsible for the lack of response to the virus, the response will be systemic involving multiple inter-related pathways. The data show that this was the case after presenting convincing transcriptome analysis.

    We thank the reviewer agreeing that we have convincingly shown that the response to the virus is systemic involving the induction of interrelated pathways

    The second hypothesis is that the differences in responses between bats and humans are due to evolutionarily divergent genes. The authors provide evidence for this in the transcriptome differences in the C-reactive protein, aspects of the complement system, iron regulation and M1/M2 macrophage polarization. The second hypothesis is broad, but there are clearly differences in the genes involved in humans and bats. Without mechanistic information on the function of the proteins/cells investigated, it is hard to determine that the changes the authors are observing are the cause of the different responses, rather than an effect of some upstream response, and so difficult to pin-point specific divergent genes.

    We agree that mechanistic studies will be required to test causal links between the genes we identified and specific anti-viral responses, an effort that is likely to require multiple laboratories and some time. The aim of this study was to enable this effort by identifying a list of candidate genes affected by EBOV and MARV infection in bats, not merely in cultured bat cells.

    The authors wish to compare the response to the virus in bats to the better characterized human tissue responses, but because this relies on previously published work in humans, it is sometimes unclear whether "more bat-like" responses are definitely associated with positive outcomes in humans. As the benefit of certain responses in human infections can depend on the timing of the response, it might be helpful to include summarized human data in manuscript to aid comparison with the bat responses.

    We agree and have added the following data and discussion (inserted into Discussion, page 9, and added two new tables, Tables 2 and 3).

    Comparing our observations to human responses to filoviruses is limited by the scarcity of studies in humans. Nevertheless, this comparison suggests potential directions to explore. In one study, individuals who succumbed to the disease showed stronger upregulation of interferon signaling and acute phase responses compared to survivors during the acute phase of infection[1], consistent with the anti-inflammatory response gene expression signature identified in this study in bats. However, most of the genes used in the study by Liu et al. to classify survivors are either barely expressed in bats or do not respond to filoviral infection (Table 2), the differences that provide potential clues to find why bats can tolerate the infection.

    A study of patients infected with Sudan Ebola virus (SUDV) analyzed protein levels for a panel of genes using a Luminex multiplex assay (using antibodies)[2]. The panel was based on results from other studies and pathways involved in the response to infections. The patients were classified into 3 possible dichotomies (fatal/non-fatal, hemorrhaging/non-hemorrhaging, or high/low viremia) correlated with genes that characterized these states. Most of these genes either are barely expressed, if at all, or are unaffected by infection in bats, except for ferritin (FTL, FTH1) whose expression is lowered by MARV infection, consistent with the observation that ferritin is higher is fatal human cases (Table 3).

    For instance, the T-cell response section concludes "Bats mount a T cell response against the infection" but there is no discussion of the impaired but complex lymphocyte response in humans, so comparison is not possible.

    We have expanded the discussion on T cells (Results, page 7) as follows.

    Previous studies on the adaptive immune response to Ebola and Marburg viruses in humans, non-human primates, and non-primate mammals, shows that long-term immunity is conferred by both T cell and antibody responses. Mostly CD8+ T cells were elicited and helpful against Ebola in mice[3],[4], while SUDV infection in humans[5]) and MARV infection in cynomolgus monkeys[6] and humans[7] ) elicited mostly CD4+ T cells . In most human EBOV infections, CD8+ T cells against the EBOV NP protein dominated the responses, while a minority of individuals harbored memory CD8+ T cells against the EBOV-GP [8].

    Consistent with this, in MARV-infected bats, CD4 expression (specific to CD4+ T cells) was higher, while in EBOV-infected bats, CD8 expression (specific to CD8+ T cells) was higher, the overall levels are low, because the tissue samples are heterogenous and expression of these markers is not high in the T cells to begin with. T cell markers (such as CCL3, ANAX1, TIMD4 and MAGT1) are also upregulated in liver, suggesting a T cell response is mounted.

    Mock infected IHC should be included in Figure 1F to demonstrate the antibodies are not background.

    We have added IHC data of two mock-infected animals (Fig. S1 panels A and B).

    See comment in hypotheses- a summarized table of findings from previous studies of early responses to the virus would be helpful for comparisons to the bat response and for determining the second hypothesis.

    We have expanded our comparisons to previous studies by adding the following text to Introduction (page 3)

    A potential source of the difficulty to understand how bats tolerate or eliminate the viruses that are deadly to humans is the lack of studies that analyze the response to infection in bats rather than in cultured bat cells. The results obtained using cell lines have been contradictory. Some studies claim both EBOV and MARV replicate to similar levels in ERB and human derived cell lines[9], with a robust innate immune response mounted by ERB and to a lesser degree, human cells, while others claim MARV inhibited the antiviral program in ERB cells, like in primate cells, and did not induce almost any IFN gene [10], or little anti-viral gene induction[11]. An experiment with the pig (PK15A) and bat (EhKiT) cells suggested they responded to EBOV through the upregulation of immune, inflammatory, and coagulation pathway, in contrast to a limited response in the human (HEK293T) cells[12]. To comprehensively understand the pathways involved in the bat filoviral response, we infected bats, rather than their isolated cells, and analyzed tissue-specific RNA expression through mRNA-seq in the organs of the infected animals.

    Reviewer #2

    The authors provide this contribution to the extremely interesting topic of the immunobiology that facilitates filovirus infections of bats without overt pathology. They focused entirely on gene transcription signatures from different tissue sites following experimental infection, and sometimes compare those signatures with those generated in humans following natural exposures to filoviruses. The strengths of the paper is the shear breadth of data generated that is available openly to the scientific community and the development of novel mRNA datasets from bats, in the absence and presence of infection. One of the major limitations of this systems-based approach is that there is no mechanistic data that links gene function to the immune response to filovirus infection. Rather, associations are made and functional links are inferred. This limitation makes the title of the manuscript "...is controlled by a systemic response" an overstatement.

    We thank the reviewer and agree that mechanistic studies were out of scope of this study and have reflected this fact in the title by replacing “is controlled” with “induces”:

    Ebola and Marburg filovirus infection in bats induces a systemic response

    The authors indicate that one of their main objectives is to understand differences in the responses to infection between bats and humans. But this submission says little about the transcriptome-level responses to filovirus infection in humans. It does, on at least one occasion, state that some of the bat genes with altered expression levels were also altered in a study of human filovirus infections (reference #67). I think it would be helpful if the authors devoted a figure or table to the direct comparison between their analysis of MARV- and EBOV-infected bats and the findings of filovirus-infected humans, highlighting genes that are differentially up- or downregulated between the two species.

    This discussion, which was also requested by Reviewer 1, is now included in the manuscript (Discussion page 9 and Tables 2 and 3).

    Figure 2 is not described nor presented usefully. Instead of providing a figure title ""Upset plot..." the authors should clearly describe the type of transcriptomic data being presented. Moreover, it way the data is plotted does not reveal any direct information about the genes that are up- or downregulated in each condition, thus reducing its utility to the reader. I suggest that this Figure be placed in the Supplemental information. In fact, Figures 3 could also be moved to the Supplemental information

    Figure 2 makes that point that the response is a broad one while Figure 3 presents evidence from expression data that there is tissue-specific responses to the viruses. Both together provide convincing evidence of a systemic, wide-ranging response to both MARV and EBOV infections. We have edited the caption to Figure 2 by changing it to the following:

    Figure 2: Broad response of bat liver genes to filoviral infection. Many genes in the liver respond to filoviral infections, with MARV having a bigger impact compared to EBOV (840 genes that are responsive to MARV alone, compared to the 43 specific to EBOV alone). The EBOV-specific (EBOV/MARV) and MARV-specific (MARV/EBOV)genes are likely host responses specific to the viral VP40, VP35 and VP24 genes. In the plot,* mock *refers to mock-infected bats, EBOV to EBOV-infected bats, and MARV to MARV-infected bat livers. Each row in the lower panel represents a set, there are six sets of genes based on various comparisons, e.g., *EBOV/mock *is the set of genes at least 2-fold up regulated in EBOV infection, compared to the mock samples. The gray bars at the lower left representing membership in the sets. The vertical blue lines with bulbs represent set intersections, e.g., the last bar is the set of genes common to EBOV/MARV, *EBOV/mock *and *MARV/mock, *so the genes in this set are up 2-fold in EBOV compared to the mock and MARV samples, and at least 2-fold up in MARV compared to mock. The main bar plot (top) is number of genes unique to that intersection, so the total belonging to a set, say mock/EBOV, is a sum of the numbers in all sets that have mock/EBOV as a member (41+203+6+31=281).

    The authors do not specify in the main text, figure captions, or methods sections how they objectively assigned bat homologs as being "similar to " or "divergent from" their human counterparts. What is the cut-off in terms of sequence similarity?

    We apologize for this omission. In addition to a description in Methods, we have added the following statement to the Results section (Page 4).

    To identify divergent genes, we relied on BLASTn[13]. Genes detected as homologues (16004, 87% out of 18443 genes in our databse) using BLASTn default settings were labelled “similar”. The remaining 2439 genes (13%) were considered “divergent”. Of these genes, 1,548 transcripts (8% of the total), could be identified as homologous by reducing the word-size in BLASTn from 11, the default, to 9. This approach is equivalent to matching at the protein level, but we find that using nucleotide level matches provides a cleaner separation of the two classes than using translated proteins (Fig. 4, Methods).

    In the Discussion, it is surprising that the authors state that "the majority of interferon response genes are not divergent from human homologs" since genes involved in innate immunity are some of the most rapidly evolving genes known to exist. Again, clarification over what dictates "divergence" over "similarity" is warranted. Many previous studies have shown how a single residue change in an innate immune effector can drastically alter its specificity and/or potency.

    We have clarified this point by adding the following statement in the Discussion (pages 8,9)

    There are hundreds of genes involved in the interferon response, some key components can mutate to change specificity of their interactions, but most, especially those in the core ISG category[14], evolve slowly and have conserved function and sequence[15]. Our analysis of gene divergence shows that the majority of interferon response genes are not divergent from their human homologs, consistent with prior observations that the innate responses are quite similar between human and bat cell lines[9]. This implies that other systems are involved in generating the difference in response between bats and humans.

    The authors state in the introduction, and point to citation #21, that ERBs are "refractory to infection." In Figure 1, the authors indicate that experimental of ERBs with EBOV led to detectable infection in some animals, particularly in the liver. At this point in the manuscript, the authors should state if and how this result differs from what is published in #21, and they should comment on whether this is scientifically significant, or not. This is eventually discussed briefly in the Discussion but adding a sentence to Results section would be helpful for readers.

    To emphasize that our results contradict prior reports of ERB being refractory to EBOV infection, we have modified the statement in the Results (page 3) as follows.

    Two of the three EBOV-inoculated animals presented with histopathological lesions in the liver, consisting of pigmented and unpigmented infiltrates of aggregated mononuclear cells compressing adjacent tissue structures, and eosinophilic nuclear and cytoplasmic inclusions, changes consistent with previous reports[16], [17]. In EBOV-infected animals, focal immunostaining with both pan-filovirus and EBOV-VP40 antibodies was observed in the liver of one animal, but very few foci were found, suggesting limited viral replication.

    The research question at hand, concerning how bats serve as reservoirs for multiple viruses which are pathogenic to humans without succumbing to disease, is one of the hottest topics in immunology and virology. However, the authors do not provide a clear enough explanation of how their approach to study the transcriptome response following filovirus infection goes beyond what has been published in previous studies. This manuscript would greatly benefit from a discussion of its novelty in the Introduction and Discussion sections.

    We have reviewed prior human and bat studies (Introduction -page 3 and Discussion- page 9 shown above) to highlight the novelty of our findings. We have also added the following sentence at the end of the Introduction highlighting the novelty of the study.

    This is the first in vivo study that focuses on the coordinated transcriptional response to filoviruses at the level of individual organs in bats.

    References

    [1] X. Liu et al., “Transcriptomic signatures differentiate survival from fatal outcomes in humans infected with Ebola virus,” Genome Biology, vol. 18, no. 1, p. 4, Jan. 2017, doi: 10.1186/s13059-016-1137-3.

    [2] A. K. McElroy et al., “Ebola hemorrhagic Fever: novel biomarker correlates of clinical outcome,” J. Infect. Dis., vol. 210, no. 4, pp. 558–566, Aug. 2014, doi: 10.1093/infdis/jiu088.

    [3] S. B. Bradfute, K. L. Warfield, and S. Bavari, “Functional CD8+ T cell responses in lethal Ebola virus infection,” J. Immunol., vol. 180, no. 6, pp. 4058–4066, Mar. 2008, doi: 10.4049/jimmunol.180.6.4058.

    [4] M. N. Rahim et al., “Complete protection of the BALB/c and C57BL/6J mice against Ebola and Marburg virus lethal challenges by pan-filovirus T-cell epigraph vaccine,” PLOS Pathogens, vol. 15, no. 2, p. e1007564, Feb. 2019, doi: 10.1371/journal.ppat.1007564.

    [5] A. Sobarzo et al., “Multiple viral proteins and immune response pathways act to generate robust long-term immunity in Sudan virus survivors,” EBioMedicine, vol. 46, pp. 215–226, Aug. 2019, doi: 10.1016/j.ebiom.2019.07.021.

    [6] L. Fernando et al., “Immune Response to Marburg Virus Angola Infection in Nonhuman Primates,” J Infect Dis, vol. 212, no. suppl_2, pp. S234–S241, Oct. 2015, doi: 10.1093/infdis/jiv095.

    [7] S. W. Stonier et al., “Marburg virus survivor immune responses are Th1 skewed with limited neutralizing antibody responses,” J. Exp. Med., vol. 214, no. 9, pp. 2563–2572, Sep. 2017, doi: 10.1084/jem.20170161.

    [8] S. Sakabe et al., “Analysis of CD8+ T cell response during the 2013–2016 Ebola epidemic in West Africa,” PNAS, vol. 115, no. 32, pp. E7578–E7586, Aug. 2018, doi: 10.1073/pnas.1806200115.

    [9] I. V. Kuzmin et al., “Innate Immune Responses of Bat and Human Cells to Filoviruses: Commonalities and Distinctions,” J. Virol., vol. 91, no. 8, Apr. 2017, doi: 10.1128/JVI.02471-16.

    [10] C. E. Arnold et al., “Transcriptomics Reveal Antiviral Gene Induction in the Egyptian Rousette Bat Is Antagonized In Vitro by Marburg Virus Infection,” Viruses, vol. 10, no. 11, 02 2018, doi: 10.3390/v10110607.

    [11] M. Hölzer et al., “Differential transcriptional responses to Ebola and Marburg virus infection in bat and human cells,” Scientific Reports, vol. 6, p. 34589, Oct. 2016, doi: 10.1038/srep34589.

    [12] J. W. Wynne et al., “Comparative Transcriptomics Highlights the Role of the Activator Protein 1 Transcription Factor in the Host Response to Ebolavirus,” Journal of Virology, vol. 91, no. 23, Dec. 2017, doi: 10.1128/JVI.01174-17.

    [13] S. F. Altschul, W. Gish, W. Miller, E. W. Myers, and D. J. Lipman, “Basic local alignment search tool,” J. Mol. Biol., vol. 215, no. 3, pp. 403–410, Oct. 1990, doi: 10.1016/S0022-2836(05)80360-2.

    [14] A. E. Shaw et al., “Fundamental properties of the mammalian innate immune system revealed by multispecies comparison of type I interferon responses,” PLOS Biology, vol. 15, no. 12, p. e2004086, Dec. 2017, doi: 10.1371/journal.pbio.2004086.

    [15] T. B. Sackton, B. P. Lazzaro, T. A. Schlenke, J. D. Evans, D. Hultmark, and A. G. Clark, “Dynamic evolution of the innate immune system in Drosophila,” Nat. Genet., vol. 39, no. 12, pp. 1461–1468, Dec. 2007, doi: 10.1038/ng.2007.60.

    [16] M. E. B. Jones et al., “Experimental Inoculation of Egyptian Rousette Bats (Rousettus aegyptiacus) with Viruses of the Ebolavirus and Marburgvirus Genera,” Viruses, vol. 7, no. 7, pp. 3420–3442, Jun. 2015, doi: 10.3390/v7072779.

    [17] J. T. Paweska, N. Storm, A. A. Grobbelaar, W. Markotter, A. Kemp, and P. Jansen van Vuren, “Experimental Inoculation of Egyptian Fruit Bats (Rousettus aegyptiacus) with Ebola Virus,” Viruses, vol. 8, no. 2, Jan. 2016, doi: 10.3390/v8020029.

  2. Review Commons

    Note: This preprint has been reviewed by subject experts for Review Commons. Content has not been altered except for formatting.

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    Referee #2

    Evidence, reproducibility and clarity

    The authors provide this contribution to the extremely interesting topic of the immunobiology that facilitates filovirus infections of bats without overt pathology. They focused entirely on gene transcription signatures from different tissue sites following experimental infection, and sometimes compare those signatures with those generated in humans following natural exposures to filoviruses. The strengths of the paper is the shear breadth of data generated that is available openly to the scientific community and the development of novel mRNA datasets from bats, in the absence and presence of infection. One of the major limitations of this systems-based approach is that there is no mechanistic data that links gene function to the immune response to filovirus infection. Rather, associations are made and functional links are inferred. This limitation makes the title of the manuscript "...is controlled by a systemic response" an overstatement.

    Major points:

    The authors indicate that one of their main objectives is to understand differences in the responses to infection between bats and humans. But this submission says little about the transcriptome-level responses to filovirus infection in humans. It does, on at least one occasion, state that some of the bat genes with altered expression levels were also altered in a study of human filovirus infections (reference #67). I think it would be helpful if the authors devoted a figure or table to the direct comparison between their analysis of MARV- and EBOV-infected bats and the findings of filovirus-infected humans, highlighting genes that are differentially up- or downregulated between the two species.

    Figure 2 is not described nor presented usefully. Instead of providing a figure title ""Upset plot..." the authors should clearly describe the type of transcriptomic data being presented. Moreover, it way the data is plotted does not reveal any direct information about the genes that are up- or downregulated in each condition, thus reducing its utility to the reader. I suggest that this Figure be placed in the Supplemental information. In fact, Figures 3 could also be moved to the Supplemental information.

    The authors do not specify in the main text, figure captions, or methods sections how they objectively assigned bat homologs as being "similar to " or "divergent from" their human counterparts. What is the cut-off in terms of sequence similarity?

    In the Discussion, it is surprising that the authors state that "the majority of interferon response genes are not divergent from human homologs" since genes involved in innate immunity are some of the most rapidly evolving genes known to exist. Again, clarification over what dictates "divergence" over "similarity" is warranted. Many previous studies have shown how a single residue change in an innate immune effector can drastically alter its specificity and/or potency.

    Minor points:

    The authors state in the introduction, and point to citation #21, that ERBs are "refractory to infection." In Figure 1, the authors indicate that experimental of ERBs with EBOV led to detectable infection in some animals, particularly in the liver. At this point in the manuscript, the authors should state if and how this result differs from what is published in #21, and they should comment on whether this is scientifically significant, or not. This is eventually discussed briefly in the Discussion but adding a sentence to Results section would be helpful for readers.

    Significance

    The research question at hand, concerning how bats serve as reservoirs for multiple viruses which are pathogenic to humans without succumbing to disease, is one of the hottest topics in immunology and virology. However, the authors do not provide a clear enough explanation of how their approach to study the transcriptome response following filovirus infection goes beyond what has been published in previous studies. This manuscript would greatly benefit from a discussion of its novelty in the Introduction and Discussion sections.

  3. Review Commons

    Note: This preprint has been reviewed by subject experts for Review Commons. Content has not been altered except for formatting.

    Learn more at Review Commons

    Referee #1

    Evidence, reproducibility and clarity

    Summary:

    The manuscript by Jayaprakash et al investigates the response to the filoviruses Marburg and Ebola virus in Rousettus aegyptiacus bats, the natural reservoir of Marburg virus. The response to infection is investigated by comparing transcriptomes of different bat tissues in infected and uninfected bats. The manuscript groups the observed transcriptome changes into pathways that are impacted, and discusses how those pathways may cause subclinical infection in bats, compared to severe disease in humans. The data included also sheds light on bat immunology and reservoir characteristics more generally, which is particularly timely during the SARS-CoV-2 pandemic.

    Major comments:

    Are the key conclusions convincing?

    The first hypothesis of the manuscript is that, rather than a change in a single immune pathway being responsible for the lack of response to the virus, the response will be systemic involving multiple inter-related pathways. The data show that this was the case after presenting convincing transcriptome analysis. The second hypothesis is that the differences in responses between bats and humans are due to evolutionarily divergent genes. The authors provide evidence for this in the transcriptome differences in the C-reactive protein, aspects of the complement system, iron regulation and M1/M2 macrophage polarization. The second hypothesis is broad, but there are clearly differences in the genes involved in humans and bats. Without mechanistic information on the function of the proteins/cells investigated, it is hard to determine that the changes the authors are observing are the cause of the different responses, rather than an effect of some upstream response, and so difficult to pin-point specific divergent genes. The authors wish to compare the response to the virus in bats to the better characterized human tissue responses, but because this relies on previously published work in humans, it is sometimes unclear whether "more bat-like" responses are definitely associated with positive outcomes in humans. As the benefit of certain responses in human infections can depend on the timing of the response, it might be helpful to include summarized human data in manuscript to aid comparison with the bat responses. For instance, the T-cell response section concludes "Bats mount a T cell response against the infection" but there is no discussion of the impaired but complex lymphocyte response in humans, so comparison is not possible.

    Should the authors qualify some of their claims as preliminary or speculative, or remove them altogether?

    No, speculative discussion of potential drugs is already qualified as speculative, and adds to the understanding of the significance of the data.

    Would additional experiments be essential to support the claims of the paper? Request additional experiments only where necessary for the paper as it is, and do not ask authors to open new lines of experimentation.

    No

    Are the suggested experiments realistic in terms of time and resources? It would help if you could add an estimated cost and time investment for substantial experiments.

    N/A

    Are the data and the methods presented in such a way that they can be reproduced?

    Yes

    Are the experiments adequately replicated and statistical analysis adequate?

    Yes

    Minor comments:

    Specific experimental issues that are easily addressable.

    Mock infected IHC should be included in Figure 1F to demonstrate the antibodies are not background.

    Are prior studies referenced appropriately?

    Mostly yes. The discussion of the T-cell responses in infection could be expanded to include more information on human responses

    Are the text and figures clear and accurate?

    Yes

    Do you have suggestions that would help the authors improve the presentation of their data and conclusions?

    See comment in hypotheses- a summarized table of findings from previous studies of early responses to the virus would be helpful for comparisons to the bat response and for determining the second hypothesis.

    Significance

    Nature and Significance of the advance.

    Bat immune responses to filoviruses are poorly characterized, and this paper contains much information that can aid future investigation of reservoir responses. This data also has broad application to other bat-borne pathogens.

    Compare to existing published knowledge.

    There is little about in vivo bat immune response to filoviral infections. Significantly, this report has a non-refractory response to Ebola virus infection in Rousettus aegyptiacus.

    Audience

    This paper would be of interest to filovirologists and those interested in zoonotics and bat immunology.

    Your expertise.

    I am a viral immunologist with >15 years' experience with filoviruses. Ms. Clarke is a senior graduate student whose thesis focuses on immune responses to filovirus glycoproteins.

  4. Version published to 10.1101/2020.04.13.039503 on bioRxiv