Skip to main content

Thank you for visiting You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

A human homologue of the Drosophila Toll protein signals activation of adaptive immunity


Induction of the adaptive immune response depends on the expression of co-stimulatory molecules and cytokines by antigen-presenting cells. The mechanisms that control the initial induction of these signals upon infection are poorly understood. It has been proposed that their expression is controlled by the non-clonal, or innate, component of immunity that preceded in evolution the development of an adaptive immune system in vertebrates1. We report here the cloning and characterization of a human homologue of the Drosophila toll protein (Toll) which has been shown to induce the innate immune response in adult Drosophila2,3,4. Like Drosophila Toll, human Toll is a type I transmembrane protein with an extracellular domain consisting of a leucine-rich repeat (LRR) domain, and a cytoplasmic domain homologous to the cytoplasmic domain of the human interleukin (IL)-1 receptor. Both Drosophila Toll and the IL-1 receptor are known to signal through the NF-κB pathway5,6,7. We show that a constitutively active mutant of human Toll transfected into human cell lines can induce the activation of NF-κB and the expression of NF-κB-controlled genes for the inflammatory cytokines IL-1, IL-6 and IL-8, as well as the expression of the co-stimulatory molecule B7.1, which is required for the activation of naive T cells.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Ancient immune defence systems of plants, insects and vertebrates.
Figure 2: a, Amino-acid sequence of human Toll.
Figure 3: Northern blots of poly(A)+RNA demonstrate predominant expression of hToll in spleen (Sp) and peripheral blood leukocytes(PBL).
Figure 4: Signalling function of hToll.

Similar content being viewed by others


  1. Janeway, C. A. J Approaching the asymptote? Evolution and revolution in immunology. Cold Spring Harbor Symp. Quant. Biol. 54, 1–13 (1989).

    Article  CAS  Google Scholar 

  2. Lemaitre, B., Nicolas, E., Michaut, L., Reichhart, J. M. & Hoffmann, J. A. The dorsoventral regulatory gene cassette spatzle/toll/cactus controls the potent antifungal response in Drosophila adults. Cell 86, 973–983 (1996).

    Article  CAS  Google Scholar 

  3. Rosetto, M., Engström, Y., Baldari, C. T., Telford, J. L. & Hultmark, D. Signals from the IL-1 receptor homolog, Toll, can activate an immune response in a Drosophila hemocyte cell line. Biochem. Biophys. Res. Commun. 209, 111–116 (1995).

    Article  CAS  Google Scholar 

  4. Ip, Y. T. & Levine, M. Molecular genetics of Drosophila immunity. Curr. Opin. Genet. Dev. 4, 672–677 (1994).

    Article  CAS  Google Scholar 

  5. Wasserman, S. A. Aconserved signal transduction pathway regulating the activity of rel-like proteins dorsal and NF-κB. Mol. Biol. Cell 4, 767–771 (1993).

    Article  CAS  Google Scholar 

  6. Hultmark, D. Insect immunology: Ancient relationships. Nature 367, 116–117 (1994).

    Article  ADS  CAS  Google Scholar 

  7. Belvin, M. P. & Anderson, K. V. Aconserved signaling pathway: the Drosophila Toll–dorsal pathway. Annu. Rev. Cell Dev. Biol. 12, 393–416 (1996).

    Article  CAS  Google Scholar 

  8. Morisato, D. & Anderson, K. V. The spatzle gene encodes a component of the extracellular signaling pathway establishing the dorsal–ventral pattern of the Drosophila embryo. Cell 76, 677–688 (1994).

    Article  CAS  Google Scholar 

  9. Gay, N. J. & Keith, F. J. Drosophila Toll and IL-1 receptor. Nature 351, 355–356 (1991).

    Article  ADS  CAS  Google Scholar 

  10. Whitham, S. et al. The product of the tobacco mosaic virus resistance gene N: similarity to toll and the interleukin-1 receptor. Cell 78, 1101–1115 (1994).

    Article  CAS  Google Scholar 

  11. Altschul, S. F., Boguski, M. S., Gish, W. & Wootton, J. C. Issues in searching molecular sequence databases. Nature Genet. 6, 119–129 (1994).

    Article  CAS  Google Scholar 

  12. Lennon, G., Auffray, C., Polymeropoulos, M. & Soares, M. B. The IMAGE Consortium: an integrated molecular analysis of genomes and their expression. Genomics 33, 151–152 (1996).

    Article  CAS  Google Scholar 

  13. Sambrook, J., Fritsch, E. F. & Maniatis, T. Molecular Cloning: A Laboratory Manual(Cold Spring Harbor Laboratory Press, New York, (1989)).

    Google Scholar 

  14. Innis, M. A., Gelfand, D. H., Sninsky, J. J. & White, T. J. (eds) PCR Protocols: A Guide to Methods and Applications(Academic, Orlando, (1992)).

    Google Scholar 

  15. Miyake, K., Yamashita, Y., Ogata, M., Sudo, T. & Kimoto, M. RP105, a novel B cell surface molecule implicated in B cell activation, is a member of the leucine-rich repeat protein family. J. Immunol. 154, 3333–3340 (1995).

    CAS  PubMed  Google Scholar 

  16. Schneider, D. S., Hudson, K. L., Lin, T. Y. & Anderson, K. V. Dominant and recessive mutations define functional domains of Toll, a transmembrane protein required for dorsal–ventral polarity in the Drosophila embryo. Genes Dev. 5, 797–807 (1991).

    Article  CAS  Google Scholar 

  17. Takahashi, N., Takahashi, Y. & Putnam, F. W. Periodicity of leucine and tandem repetition of a 24-amino acid segment in the primary structure of leucine-rich alpha 2-glycoprotein of human serum. Proc. Natl Acad. Sci. USA 82, 1906–1910 (1985).

    Article  ADS  CAS  Google Scholar 

  18. Winans, K. A. & Hashimoto, C. Ventralization of the Drosophila embryo by deletion of extracellular leucine-rich repeats in the Toll protein. Mol. Biol. Cell. 6, 587–596 (1995).

    Article  CAS  Google Scholar 

  19. Fearon, D. T. & Locksley, R. M. The instructive role of innate immunity in the acquired immune response. Science 272, 50–53 (1996).

    Article  ADS  CAS  Google Scholar 

  20. Medzhitov, R. & Janeway, C. A. J On the semantics of immune recognition. Res. Immunol. 147, 208–214 (1996).

    Article  CAS  Google Scholar 

  21. Yamamura, M. et al. Defining protective responses to pathogens: cytokine profiles in leprosy lesions. Science 254, 277–279 (1991).

    Article  ADS  CAS  Google Scholar 

Download references


We thank our colleagues for discussions; P. G. Waterbury for DNA sequencing; S.Ghosh and R. Voll for pB2XLuc plasmid and for helpful suggestions; and J. Flaxenberg for assistance. We acknowledge the Howard Hughes Medical Institute and the NIAID, NIH for support of this work.

Author information

Authors and Affiliations


Corresponding author

Correspondence to Charles A. Janeway Jr.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Medzhitov, R., Preston-Hurlburt, P. & Janeway, C. A human homologue of the Drosophila Toll protein signals activation of adaptive immunity. Nature 388, 394–397 (1997).

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI:

This article is cited by


By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.


Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing