Skip to main content

Main menu

  • Home
  • Articles
    • Current
    • Special Feature Articles - Most Recent
    • Special Features
    • Colloquia
    • Collected Articles
    • PNAS Classics
    • List of Issues
  • Front Matter
    • Front Matter Portal
    • Journal Club
  • News
    • For the Press
    • This Week In PNAS
    • PNAS in the News
  • Podcasts
  • Authors
    • Information for Authors
    • Editorial and Journal Policies
    • Submission Procedures
    • Fees and Licenses
  • Submit
  • Submit
  • About
    • Editorial Board
    • PNAS Staff
    • FAQ
    • Accessibility Statement
    • Rights and Permissions
    • Site Map
  • Contact
  • Journal Club
  • Subscribe
    • Subscription Rates
    • Subscriptions FAQ
    • Open Access
    • Recommend PNAS to Your Librarian

User menu

  • Log in
  • My Cart

Search

  • Advanced search
Home
Home
  • Log in
  • My Cart

Advanced Search

  • Home
  • Articles
    • Current
    • Special Feature Articles - Most Recent
    • Special Features
    • Colloquia
    • Collected Articles
    • PNAS Classics
    • List of Issues
  • Front Matter
    • Front Matter Portal
    • Journal Club
  • News
    • For the Press
    • This Week In PNAS
    • PNAS in the News
  • Podcasts
  • Authors
    • Information for Authors
    • Editorial and Journal Policies
    • Submission Procedures
    • Fees and Licenses
  • Submit
Research Article

Local induction of bladder Th1 responses to combat urinary tract infections

View ORCID ProfileJianxuan Wu, Chunjing Bao, View ORCID ProfileR. Lee Reinhardt, and Soman N. Abraham
  1. aDepartment of Immunology, Duke University Medical Center, Durham, NC 27710;
  2. bDepartment of Pathology, Duke University Medical Center, Durham, NC 27710;
  3. cDepartment of Biomedical Research, National Jewish Health, Denver, CO 80206;
  4. dDepartment of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045;
  5. eDepartment of Molecular Genetics & Microbiology, Duke University Medical Center, Durham, NC 27710;
  6. fProgram in Emerging Infectious Diseases, Duke–National University of Singapore, 169857 Singapore

See allHide authors and affiliations

PNAS March 9, 2021 118 (10) e2026461118; https://doi.org/10.1073/pnas.2026461118
Jianxuan Wu
aDepartment of Immunology, Duke University Medical Center, Durham, NC 27710;
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for Jianxuan Wu
Chunjing Bao
bDepartment of Pathology, Duke University Medical Center, Durham, NC 27710;
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
R. Lee Reinhardt
cDepartment of Biomedical Research, National Jewish Health, Denver, CO 80206;
dDepartment of Immunology and Microbiology, University of Colorado Anschutz Medical Campus, Aurora, CO 80045;
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • ORCID record for R. Lee Reinhardt
Soman N. Abraham
aDepartment of Immunology, Duke University Medical Center, Durham, NC 27710;
bDepartment of Pathology, Duke University Medical Center, Durham, NC 27710;
eDepartment of Molecular Genetics & Microbiology, Duke University Medical Center, Durham, NC 27710;
fProgram in Emerging Infectious Diseases, Duke–National University of Singapore, 169857 Singapore
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • For correspondence: soman.abraham@duke.edu
  1. Edited by Rino Rappuoli, GlaxoSmithKline, Siena, Italy, and approved January 22, 2021 (received for review January 5, 2021)

  • Article
  • Figures & SI
  • Info & Metrics
  • PDF
Loading

Significance

Urinary tract infections (UTIs) are the second most common bacterial infections. Caring for UTI patients is very difficult and often perplexing. We typically view our immune system as an adaptive line of defense that becomes more responsive to specific pathogens after episodes of infection. However, the opposite is seen in these patients, in whom each infection actually increases the risk of a subsequent infection. Our group recently identified the underlying basis as a highly Th2-biased response in bladder that inhibits Th1-mediated bacterial clearance. To resolve this situation, we investigated whether immunizing mice intravesically with bacterial antigens combined with a Th1-skewing adjuvant (CpG) would evoke a more balanced and protective immune response.

Abstract

Given the high frequency of urinary tract infections (UTIs) and their recurrence, there is keen interest in developing effective UTI vaccines. Currently, most vaccine studies, including those in humans, involve parenteral vaccination aimed at evoking and sustaining elevated levels of systemic antibody directed at the uropathogens. In view of recent reports of aberrant Th2-biased bladder immune responses to infection, we hypothesized that immunizing mice intravesically with antigens from uropathogenic Escherichia coli (UPEC) combined with a Th1-skewing adjuvant could correct this defect and promote protection against UTIs. Here we report that compared with mice immunized subcutaneously with this vaccine combination, intravesically immunized mice were markedly more protected from UTIs because of their distinctive ability to recruit Th1 cells into the bladder. This mode of vaccination was effective even in mice that experienced multiple UTIs and displayed pronounced aberrant bladder immune responses. Thus, intravesical vaccination with one or more UPEC antigens to induce bladder Th1 responses represents a superior strategy to combat UTIs, especially in UTI-prone subjects.

  • bladder
  • UTI
  • Th1
  • vaccine

Footnotes

  • ↵1To whom correspondence may be addressed. Email: soman.abraham{at}duke.edu.
  • Author contributions: J.W., R.L.R., and S.N.A. designed research; J.W. and C.B. performed research; R.L.R. contributed new reagents/analytic tools; J.W. and S.N.A. analyzed data; and J.W., C.B., R.L.R., and S.N.A. wrote the paper.

  • The authors declare no competing interest.

  • This article is a PNAS Direct Submission.

  • This article contains supporting information online at https://www.pnas.org/lookup/suppl/doi:10.1073/pnas.2026461118/-/DCSupplemental.

Data Availability

All study data are included in the main text and SI Appendix.

Published under the PNAS license.

View Full Text

References

  1. ↵
    1. B. Foxman
    , Urinary tract infection syndromes: Occurrence, recurrence, bacteriology, risk factors, and disease burden. Infect. Dis. Clin. North Am. 28, 1–13 (2014).
    OpenUrlCrossRefPubMed
  2. ↵
    1. A. Al-Badr,
    2. G. Al-Shaikh
    , Recurrent urinary tract infections management in women: A review. Sultan Qaboos Univ. Med. J. 13, 359–367 (2013).
    OpenUrlCrossRefPubMed
  3. ↵
    1. A. L. Flores-Mireles,
    2. J. N. Walker,
    3. M. Caparon,
    4. S. J. Hultgren
    , Urinary tract infections: Epidemiology, mechanisms of infection and treatment options. Nat. Rev. Microbiol. 13, 269–284 (2015).
    OpenUrlCrossRefPubMed
  4. ↵
    1. T. M. Hooton
    , Recurrent urinary tract infection in women. Int. J. Antimicrob. Agents 17, 259–268 (2001).
    OpenUrlCrossRefPubMed
  5. ↵
    1. B. Foxman
    , Recurring urinary tract infection: Incidence and risk factors. Am. J. Public Health 80, 331–333 (1990).
    OpenUrlCrossRefPubMed
  6. ↵
    1. R. Ikäheimo et al
    ., Recurrence of urinary tract infection in a primary care setting: Analysis of a 1-year follow-up of 179 women. Clin. Infect. Dis. 22, 91–99 (1996).
    OpenUrlCrossRefPubMed
  7. ↵
    1. J. Wu et al
    ., A highly polarized TH2 bladder response to infection promotes epithelial repair at the expense of preventing new infections. Nat. Immunol. 21, 671–683 (2020).
    OpenUrl
  8. ↵
    1. M. G. Kaye,
    2. M. J. Fox,
    3. J. G. Bartlett,
    4. S. S. Braman,
    5. J. Glassroth
    , The clinical spectrum of Staphylococcus aureus pulmonary infection. Chest 97, 788–792 (1990).
    OpenUrlCrossRefPubMed
  9. ↵
    1. M. Rodríguez-Créixems et al
    ., Recurrent pneumococcal bacteremia. A warning of immunodeficiency. Arch. Intern. Med. 156, 1429–1434 (1996).
    OpenUrlCrossRefPubMed
  10. ↵
    1. J. Hedlund,
    2. M. Kalin,
    3. A. Örtqvist
    , Recurrence of pneumonia in middle-aged and elderly adults after hospital-treated pneumonia: Aetiology and predisposing conditions. Scand. J. Infect. Dis. 29, 387–392 (1997).
    OpenUrlCrossRefPubMed
  11. ↵
    1. Y. Niv,
    2. R. Hazazi
    , Helicobacter pylori recurrence in developed and developing countries: Meta-analysis of 13C-urea breath test follow-up after eradication. Helicobacter 13, 56–61 (2008).
    OpenUrlCrossRefPubMed
  12. ↵
    1. F. A. Zar,
    2. S. R. Bakkanagari,
    3. K. M. Moorthi,
    4. M. B. Davis
    , A comparison of vancomycin and metronidazole for the treatment of Clostridium difficile-associated diarrhea, stratified by disease severity. Clin. Infect. Dis. 45, 302–307 (2007).
    OpenUrlCrossRefPubMed
  13. ↵
    1. T. J. Borody et al
    ., Recurrence of duodenal ulcer and Campylobacter pylori infection after eradication. Med. J. Aust. 151, 431–435 (1989).
    OpenUrlPubMed
  14. ↵
    1. C. Y. Chan,
    2. A. L. St. John,
    3. S. N. Abraham
    , Mast cell interleukin-10 drives localized tolerance in chronic bladder infection. Immunity 38, 349–359 (2013).
    OpenUrlCrossRefPubMed
  15. ↵
    1. M. A. Mulvey,
    2. J. D. Schilling,
    3. S. J. Hultgren
    , Establishment of a persistent Escherichia coli reservoir during the acute phase of a bladder infection. Infect. Immun. 69, 4572–4579 (2001).
    OpenUrlAbstract/FREE Full Text
  16. ↵
    1. J. Wu,
    2. Y. Miao,
    3. S. N. Abraham
    , The multiple antibacterial activities of the bladder epithelium. Ann. Transl. Med. 5, 35 (2017).
    OpenUrl
  17. ↵
    1. K. E. Sivick,
    2. H. L. Mobley
    , Waging war against uropathogenic Escherichia coli: Winning back the urinary tract. Infect. Immun. 78, 568–585 (2010).
    OpenUrlAbstract/FREE Full Text
  18. ↵
    1. A. R. Brumbaugh,
    2. H. L. Mobley
    , Preventing urinary tract infection: Progress toward an effective Escherichia coli vaccine. Expert Rev. Vaccines 11, 663–676 (2012).
    OpenUrlCrossRefPubMed
  19. ↵
    1. R. D. Klein,
    2. S. J. Hultgren
    , Urinary tract infections: Microbial pathogenesis, host-pathogen interactions and new treatment strategies. Nat. Rev. Microbiol. 18, 211–226 (2020).
    OpenUrl
  20. ↵
    1. S. N. Abraham,
    2. D. Sun,
    3. J. B. Dale,
    4. E. H. Beachey
    , Conservation of the D-mannose-adhesion protein among type 1 fimbriated members of the family Enterobacteriaceae. Nature 336, 682–684 (1988).
    OpenUrlCrossRefPubMed
  21. ↵
    1. S. Langermann et al
    ., Vaccination with FimH adhesin protects cynomolgus monkeys from colonization and infection by uropathogenic Escherichia coli. J. Infect. Dis. 181, 774–778 (2000).
    OpenUrlCrossRefPubMed
  22. ↵
    1. M. R. Asadi Karam,
    2. M. Oloomi,
    3. M. Mahdavi,
    4. M. Habibi,
    5. S. Bouzari
    , Vaccination with recombinant FimH fused with flagellin enhances cellular and humoral immunity against urinary tract infection in mice. Vaccine 31, 1210–1216 (2013).
    OpenUrlCrossRef
  23. ↵
    1. D. T. Uehling,
    2. W. J. Hopkins,
    3. L. J. James,
    4. E. Balish
    , Vaginal immunization of monkeys against urinary tract infection with a multi-strain vaccine. J. Urol. 151, 214–216 (1994).
    OpenUrlPubMed
  24. ↵
    1. L. A. Mike,
    2. S. N. Smith,
    3. C. A. Sumner,
    4. K. A. Eaton,
    5. H. L. Mobley
    , Siderophore vaccine conjugates protect against uropathogenic Escherichia coli urinary tract infection. Proc. Natl. Acad. Sci. U.S.A. 113, 13468–13473 (2016).
    OpenUrlAbstract/FREE Full Text
  25. ↵
    1. V. S. Forsyth et al
    ., Optimization of an experimental vaccine to prevent Escherichia coli urinary tract infection. MBio 11, e00555-20 (2020).
    OpenUrlAbstract/FREE Full Text
  26. ↵
    1. S. N. Abraham,
    2. Y. Miao
    , The nature of immune responses to urinary tract infections. Nat. Rev. Immunol. 15, 655–663 (2015).
    OpenUrlCrossRefPubMed
  27. ↵
    1. Z. Li,
    2. K. E. Wang,
    3. X. L. Zhou,
    4. J. Zhou,
    5. C. H. Ye
    , Preoperative Th1/Th2 and related cytokines: Prediction value in postoperative febrile UTI after ureteroscopy in patients with ureteral calculi. Adv. Clin. Exp. Med. 28, 125–132 (2019).
    OpenUrl
  28. ↵
    1. C. Bode,
    2. G. Zhao,
    3. F. Steinhagen,
    4. T. Kinjo,
    5. D. M. Klinman
    , CpG DNA as a vaccine adjuvant. Expert Rev. Vaccines 10, 499–511 (2011).
    OpenUrlCrossRefPubMed
  29. ↵
    1. S. Ribes et al
    ., Intraperitoneal prophylaxis with CpG oligodeoxynucleotides protects neutropenic mice against intracerebral Escherichia coli K1 infection. J. Neuroinflammation 11, 14 (2014).
    OpenUrlCrossRefPubMed
  30. ↵
    1. A. L. St John,
    2. W. X. G. Ang,
    3. A. P. S. Rathore,
    4. S. N. Abraham
    , Reprograming immunity to food allergens. J. Allergy Clin. Immunol. 141, 1936–1939.e2 (2018).
    OpenUrlCrossRefPubMed
  31. ↵
    1. S. E. Macatonia et al
    ., Dendritic cells produce IL-12 and direct the development of Th1 cells from naive CD4+ T cells. J. Immunol. 154, 5071–5079 (1995).
    OpenUrlAbstract
  32. ↵
    1. R. L. Reinhardt,
    2. H. E. Liang,
    3. R. M. Locksley
    , Cytokine-secreting follicular T cells shape the antibody repertoire. Nat. Immunol. 10, 385–393 (2009).
    OpenUrlCrossRefPubMed
  33. ↵
    1. R. L. Reinhardt et al
    ., A novel model for IFN-γ-mediated autoinflammatory syndromes. J. Immunol. 194, 2358–2368 (2015).
    OpenUrlAbstract/FREE Full Text
  34. ↵
    1. S. Normark et al
    ., Genetics of digalactoside-binding adhesin from a uropathogenic Escherichia coli strain. Infect. Immun. 41, 942–949 (1983).
    OpenUrlAbstract/FREE Full Text
  35. ↵
    1. G. Gautam,
    2. R. Khera
    , Vaginal mucosal vaccine for recurrent urinary tract infections. Indian J. Urol. 23, 335–336 (2007).
    OpenUrlPubMed
  36. ↵
    1. A. Mount et al
    ., Combination of adjuvants: The future of vaccine design. Expert Rev. Vaccines 12, 733–746 (2013).
    OpenUrlCrossRefPubMed
  37. ↵
    1. T. A. Wynn et al
    ., An IL-12-based vaccination method for preventing fibrosis induced by schistosome infection. Nature 376, 594–596 (1995).
    OpenUrlCrossRefPubMed
  38. ↵
    1. Y. Kumamoto et al
    ., CD301b+ dermal dendritic cells drive T helper 2 cell-mediated immunity. Immunity 39, 733–743 (2013).
    OpenUrlCrossRefPubMed
  39. ↵
    1. D. Sen,
    2. L. Forrest,
    3. T. B. Kepler,
    4. I. Parker,
    5. M. D. Cahalan
    , Selective and site-specific mobilization of dermal dendritic cells and Langerhans cells by Th1- and Th2-polarizing adjuvants. Proc. Natl. Acad. Sci. U.S.A. 107, 8334–8339 (2010).
    OpenUrlAbstract/FREE Full Text
  40. ↵
    1. J. Zhu,
    2. W. E. Paul
    , CD4 T cells: Fates, functions, and faults. Blood 112, 1557–1569 (2008).
    OpenUrlAbstract/FREE Full Text
  41. ↵
    1. P. E. Fields,
    2. S. T. Kim,
    3. R. A. Flavell
    , Cutting edge: Changes in histone acetylation at the IL-4 and IFN-γ loci accompany Th1/Th2 differentiation. J. Immunol. 169, 647–650 (2002).
    OpenUrlAbstract/FREE Full Text
  42. ↵
    1. H. Bashyam
    , Th1/Th2 cross-regulation and the discovery of IL-10. J. Exp. Med. 204, 237 (2007).
    OpenUrlAbstract/FREE Full Text
  43. ↵
    1. J. R. Lukens,
    2. P. K. Anand
    , Adapt(ed) to repair—TH 2 immune responses in the bladder promote recurrent infections. Nat. Immunol. 21, 597–599 (2020).
    OpenUrl
  44. ↵
    1. M. Mohrs,
    2. K. Shinkai,
    3. K. Mohrs,
    4. R. M. Locksley
    , Analysis of type 2 immunity in vivo with a bicistronic IL-4 reporter. Immunity 15, 303–311 (2001).
    OpenUrlCrossRefPubMed
  45. ↵
    1. M. R. Karam,
    2. M. Oloomi,
    3. M. Mahdavi,
    4. M. Habibi,
    5. S. Bouzari
    , Assessment of immune responses of the flagellin (FliC) fused to FimH adhesin of uropathogenic Escherichia coli. Mol. Immunol. 54, 32–39 (2013).
    OpenUrl
  46. ↵
    1. S. Bobat et al
    ., Soluble flagellin, FliC, induces an Ag-specific Th2 response, yet promotes T-bet-regulated Th1 clearance of Salmonella typhimurium infection. Eur. J. Immunol. 41, 1606–1618 (2011).
    OpenUrlCrossRefPubMed
  47. ↵
    1. C. A. Sarkissian,
    2. C. J. Alteri,
    3. H. L. T. Mobley
    , UTI patients have pre-existing antigen-specific antibody titers against UTI vaccine antigens. Vaccine 37, 4937–4946 (2019).
    OpenUrl
  48. ↵
    1. A. N. Hegazy et al., Oxford IBD Cohort Investigators
    , Circulating and tissue-resident CD4+ T cells with reactivity to intestinal microbiota are abundant in healthy individuals and function is altered during inflammation. Gastroenterology 153, 1320–1337.e16 (2017).
    OpenUrlCrossRef
  49. ↵
    1. D. L. Farber,
    2. N. A. Yudanin,
    3. N. P. Restifo
    , Human memory T cells: Generation, compartmentalization and homeostasis. Nat. Rev. Immunol. 14, 24–35 (2014).
    OpenUrlCrossRefPubMed
  50. ↵
    1. K. Honda,
    2. D. R. Littman
    , The microbiota in adaptive immune homeostasis and disease. Nature 535, 75–84 (2016).
    OpenUrlCrossRefPubMed
  51. ↵
    1. L. Brubaker,
    2. A. Wolfe
    , The urinary microbiota: A paradigm shift for bladder disorders? Curr. Opin. Obstet. Gynecol. 28, 407–412 (2016).
    OpenUrlCrossRef
  52. ↵
    1. T. Antunes-Lopes et al
    ., The role of urinary microbiota in lower urinary tract dysfunction: A systematic review. Eur. Urol. Focus 6, 361–369 (2018).
    OpenUrl
  53. ↵
    1. S. Langermann,
    2. W. R. Ballou Jr
    , Vaccination utilizing the FimCH complex as a strategy to prevent Escherichia coli urinary tract infections. J. Infect. Dis. 183 (suppl. 1), S84–S86 (2001).
    OpenUrlCrossRefPubMed
  54. ↵
    1. C. Biot et al
    ., Preexisting BCG-specific T cells improve intravesical immunotherapy for bladder cancer. Sci. Transl. Med. 4, 137ra72 (2012).
    OpenUrlAbstract/FREE Full Text
  55. ↵
    1. L. Derré et al
    ., Intravesical bacillus Calmette–Guerin combined with a cancer vaccine increases local T-cell responses in non-muscle-invasive bladder cancer patients. Clin. Cancer Res. 23, 717–725 (2017).
    OpenUrlAbstract/FREE Full Text
  56. ↵
    1. M. Kates et al
    ., Intravesical BCG induces CD4+ T-cell expansion in an immune competent model of bladder cancer. Cancer Immunol. Res. 5, 594–603 (2017).
    OpenUrlAbstract/FREE Full Text
  57. ↵
    1. G. Redelman-Sidi,
    2. M. S. Glickman,
    3. B. H. Bochner
    , The mechanism of action of BCG therapy for bladder cancer—a current perspective. Nat. Rev. Urol. 11, 153–162 (2014).
    OpenUrlCrossRefPubMed
  58. ↵
    1. S. Domingos-Pereira et al
    ., Intravesical Ty21a vaccine promotes dendritic cells and T cell-mediated tumor regression in the MB49 bladder cancer model. Cancer Immunol. Res. 7, 621–629 (2019).
    OpenUrlAbstract/FREE Full Text
  59. ↵
    1. World Health Organization
    , Water sanitation hygiene. Boil water: Technical brief. https://www.who.int/water_sanitation_health/publications/boiling-water/en/. Accessed 31 January 2015.
  60. ↵
    1. L. Mocé-Llivina,
    2. M. Muniesa,
    3. H. Pimenta-Vale,
    4. F. Lucena,
    5. J. Jofre
    , Survival of bacterial indicator species and bacteriophages after thermal treatment of sludge and sewage. Appl. Environ. Microbiol. 69, 1452–1456 (2003).
    OpenUrlAbstract/FREE Full Text

Log in using your username and password

Forgot your user name or password?

Log in through your institution

You may be able to gain access using your login credentials for your institution. Contact your library if you do not have a username and password.
If your organization uses OpenAthens, you can log in using your OpenAthens username and password. To check if your institution is supported, please see this list. Contact your library for more details.

Purchase access

You may purchase access to this article. This will require you to create an account if you don't already have one.

Subscribers, for more details, please visit our Subscriptions FAQ.

Please click here to log into the PNAS submission website.

PreviousNext
Back to top
Article Alerts
Email Article

Thank you for your interest in spreading the word on PNAS.

NOTE: We only request your email address so that the person you are recommending the page to knows that you wanted them to see it, and that it is not junk mail. We do not capture any email address.

Enter multiple addresses on separate lines or separate them with commas.
Local induction of bladder Th1 responses to combat urinary tract infections
(Your Name) has sent you a message from PNAS
(Your Name) thought you would like to see the PNAS web site.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Local induction of bladder Th1 responses to combat urinary tract infections
Jianxuan Wu, Chunjing Bao, R. Lee Reinhardt, Soman N. Abraham
Proceedings of the National Academy of Sciences Mar 2021, 118 (10) e2026461118; DOI: 10.1073/pnas.2026461118

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero
Request Permissions
Share
Local induction of bladder Th1 responses to combat urinary tract infections
Jianxuan Wu, Chunjing Bao, R. Lee Reinhardt, Soman N. Abraham
Proceedings of the National Academy of Sciences Mar 2021, 118 (10) e2026461118; DOI: 10.1073/pnas.2026461118
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Mendeley logo Mendeley

Article Classifications

  • Biological Sciences
  • Immunology and Inflammation
Proceedings of the National Academy of Sciences: 118 (10)
Table of Contents

Submit

Sign up for Article Alerts

Jump to section

  • Article
    • Abstract
    • Results
    • Discussion
    • Methods
    • Data Availability
    • Acknowledgments
    • Footnotes
    • References
  • Figures & SI
  • Info & Metrics
  • PDF

You May Also be Interested in

Water from a faucet fills a glass.
News Feature: How “forever chemicals” might impair the immune system
Researchers are exploring whether these ubiquitous fluorinated molecules might worsen infections or hamper vaccine effectiveness.
Image credit: Shutterstock/Dmitry Naumov.
Reflection of clouds in the still waters of Mono Lake in California.
Inner Workings: Making headway with the mysteries of life’s origins
Recent experiments and simulations are starting to answer some fundamental questions about how life came to be.
Image credit: Shutterstock/Radoslaw Lecyk.
Cave in coastal Kenya with tree growing in the middle.
Journal Club: Small, sharp blades mark shift from Middle to Later Stone Age in coastal Kenya
Archaeologists have long tried to define the transition between the two time periods.
Image credit: Ceri Shipton.
Mouse fibroblast cells. Electron bifurcation reactions keep mammalian cells alive.
Exploring electron bifurcation
Jonathon Yuly, David Beratan, and Peng Zhang investigate how electron bifurcation reactions work.
Listen
Past PodcastsSubscribe
Panda bear hanging in a tree
How horse manure helps giant pandas tolerate cold
A study finds that giant pandas roll in horse manure to increase their cold tolerance.
Image credit: Fuwen Wei.

Similar Articles

Site Logo
Powered by HighWire
  • Submit Manuscript
  • Twitter
  • Facebook
  • RSS Feeds
  • Email Alerts

Articles

  • Current Issue
  • Special Feature Articles – Most Recent
  • List of Issues

PNAS Portals

  • Anthropology
  • Chemistry
  • Classics
  • Front Matter
  • Physics
  • Sustainability Science
  • Teaching Resources

Information

  • Authors
  • Editorial Board
  • Reviewers
  • Subscribers
  • Librarians
  • Press
  • Cozzarelli Prize
  • Site Map
  • PNAS Updates
  • FAQs
  • Accessibility Statement
  • Rights & Permissions
  • About
  • Contact

Feedback    Privacy/Legal

Copyright © 2021 National Academy of Sciences. Online ISSN 1091-6490