Skip to main content

Thank you for visiting nature.com. 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:

Experimental therapy of African trypanosomiasis with a nanobody-conjugated human trypanolytic factor

Abstract

High systemic drug toxicity and increasing prevalence of drug resistance hampers efficient treatment of human African trypanosomiasis (HAT). Hence, development of new highly specific trypanocidal drugs is necessary. Normal human serum (NHS) contains apolipoprotein L-I (apoL-I), which lyses African trypanosomes except resistant forms such as Trypanosoma brucei rhodesiense1. T. b. rhodesiense expresses the apoL-I–neutralizing serum resistance–associated (SRA) protein2, endowing this parasite with the ability to infect humans and cause HAT. A truncated apoL-I (Tr-apoL-I) has been engineered by deleting its SRA-interacting domain, which makes it lytic for T. b. rhodesiense1. Here, we conjugated Tr-apoL-I with a single-domain antibody (nanobody) that efficiently targets conserved cryptic epitopes of the variant surface glycoprotein (VSG) of trypanosomes3 to generate a new manmade type of immunotoxin with potential for trypanosomiasis therapy. Treatment with this engineered conjugate resulted in clear curative and alleviating effects on acute and chronic infections of mice with both NHS-resistant and NHS-sensitive trypanosomes.

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

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

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

Figure 1: Targeting modules for the trypanosome surface.
Figure 2: In vitro trypanolysis.
Figure 3: Therapeutic effects of NbAn33–Tr-apoL-I in acute infection.
Figure 4: Therapeutic effects of NbAn33–Tr-apoL-I treatment at the second peak of parasitemia.

Similar content being viewed by others

Accession codes

Accessions

GenBank/EMBL/DDBJ

References

  1. Vanhamme, L. et al. Apolipoprotein L–I is the trypanosome lytic factor of human serum. Nature 422, 83–87 (2003).

    Article  CAS  Google Scholar 

  2. Xong, H.V. et al. A VSG expression site-associated gene confers resistance to human serum in Trypanosoma rhodesiense. Cell 95, 839–846 (1998).

    Article  CAS  Google Scholar 

  3. Stijlemans, B. et al. Efficient targeting of conserved cryptic epitopes of infectious agents by single domain antibodies. African trypanosomes as paradigm. J. Biol. Chem. 279, 1256–1261 (2004).

    Article  CAS  Google Scholar 

  4. Hutchinson, O.C., Fevre, E.M., Carrington, M. & Welburn, S.C. Lessons learned from the emergence of a new Trypanosoma brucei rhodesiense sleeping sickness focus in Uganda. Lancet Infect. Dis. 3, 42–45 (2003).

    Article  CAS  Google Scholar 

  5. Barrett, M.P. et al. The trypanosomiases. Lancet 362, 1469–1480 (2003).

    Article  Google Scholar 

  6. Welburn, S.C. et al. Identification of human-infective trypanosomes in animal reservoir of sleeping sickness in Uganda by means of serum-resistance-associated (SRA) gene. Lancet 358, 2017–2019 (2001).

    Article  CAS  Google Scholar 

  7. Welburn, S.C., Fevre, E.M., Coleman, P.G., Odiit, M. & Maudlin, I. Sleeping sickness: a tale of two diseases. Trends Parasitol. 17, 19–24 (2001).

    Article  CAS  Google Scholar 

  8. Pays, E., Vanhamme, L. & Perez-Morga, D. Antigenic variation in Trypanosoma brucei: facts, challenges and mysteries. Curr. Opin. Microbiol. 7, 369–374 (2004).

    Article  CAS  Google Scholar 

  9. Horn, D. The molecular control of antigenic variation in Trypanosoma brucei. Curr. Mol. Med. 4, 563–576 (2004).

    Article  CAS  Google Scholar 

  10. Legros, D. et al. Treatment of human African trypanosomiasis — present situation and needs for research and development. Lancet Infect. Dis. 2, 437–440 (2002).

    Article  Google Scholar 

  11. Burri, C. et al. Efficacy of new, concise schedule for melarsoprol in treatment of sleeping sickness caused by Trypanosoma brucei gambiense: a randomised trial. Lancet 355, 1419–1425 (2000).

    Article  CAS  Google Scholar 

  12. Pepin, J. & Milord, F. The treatment of human African trypanosomiasis. Adv. Parasitol. 33, 1–47 (1994).

    Article  CAS  Google Scholar 

  13. Bacchi, C.J. Resistance to clinical drugs in African trypanosomes. Parasitol. Today 9, 190–193 (1993).

    Article  CAS  Google Scholar 

  14. Vanhamme, L. & Pays, E. The trypanosome lytic factor of human serum and the molecular basis of sleeping sickness. Int. J. Parasitol. 34, 887–898 (2004).

    Article  CAS  Google Scholar 

  15. De Greef, C. & Hamers, R. The serum resistance-associated (SRA) gene of Trypanosoma brucei rhodesiense encodes a variant surface glycoprotein-like protein. Mol. Biochem. Parasitol. 68, 277–284 (1994).

    Article  CAS  Google Scholar 

  16. Van Meirvenne, N., Maginus, E. & Janssens, P.G. The effect of normal human serum on trypanosomes of distinct antigenic type (ETat 1 to 12) isolated from a strain of Trypanosoma brucei rhodesiense. Ann. Soc. Belg. Med. Trop. 56, 55–63 (1976).

    CAS  PubMed  Google Scholar 

  17. Duchateau, P.N. et al. Plasma apolipoprotein L concentrations correlate with plasma triglycerides and cholesterol levels in normolipidemic, hyperlipidemic, and diabetic subjects. J. Lipid Res. 41, 1231–1236 (2000).

    CAS  PubMed  Google Scholar 

  18. Duchateau, P.N. et al. Apolipoprotein L, a new human high density lipoprotein apolipoprotein expressed by the pancreas. Identification, cloning, characterization, and plasma distribution of apolipoprotein L. J. Biol. Chem. 272, 25576–25582 (1997).

    Article  CAS  Google Scholar 

  19. Nguyen, V.K., Desmyter, A. & Muyldermans, S. Functional heavy-chain antibodies in Camelidae. Adv. Immunol. 79, 261–296 (2001).

    Article  CAS  Google Scholar 

  20. Muyldermans, S. Single domain camel antibodies: current status. J. Biotechnol. 74, 277–302 (2001).

    CAS  PubMed  Google Scholar 

  21. Els Conrath, K., Lauwereys, M., Wyns, L. & Muyldermans, S. Camel single-domain antibodies as modular building units in bispecific and bivalent antibody constructs. J. Biol. Chem. 276, 7346–7350 (2001).

    Article  CAS  Google Scholar 

  22. Mehlert, A., Bond, C.S. & Ferguson, M.A. The glycoforms of a Trypanosoma brucei variant surface glycoprotein and molecular modeling of a glycosylated surface coat. Glycobiology 12, 607–612 (2002).

    Article  CAS  Google Scholar 

  23. Perez-Morga, D. et al. Apolipoprotein L–I promotes trypanosome lysis by forming pores in lysosomal membranes. Science 309, 469–472 (2005).

    Article  CAS  Google Scholar 

  24. Cortez-Retamozo, V. et al. Efficient cancer therapy with a nanobody-based conjugate. Cancer Res. 64, 2853–2857 (2004).

    Article  CAS  Google Scholar 

  25. Magez, S., Radwanska, M., Beschin, A., Sekikawa, K. & De Baetselier, P. Tumor necrosis factor alpha is a key mediator in the regulation of experimental Trypanosoma brucei infections. Infect. Immun. 67, 3128–3132 (1999).

    CAS  PubMed  PubMed Central  Google Scholar 

  26. Magez, S. et al. P75 tumor necrosis factor-receptor shedding occurs as a protective host response during African trypanosomiasis. J. Infect. Dis. 189, 527–539 (2004).

    Article  Google Scholar 

  27. Chisi, J.E., Misiri, H., Zverev, Y., Nkhoma, A. & Sternberg, J.M. Anaemia in human African trypanosomiasis caused by Trypanosoma brucei rhodesiense. East Afr. Med. J. 81, 505–508 (2004).

    Article  CAS  Google Scholar 

  28. Naessens, J. et al. TNF-α mediates the development of anaemia in a murine Trypanosoma brucei rhodesiense infection, but not the anaemia associated with a murine Trypanosoma congolense infection. Clin. Exp. Immunol. 139, 405–410 (2005).

    Article  CAS  Google Scholar 

  29. Cortez-Retamozo, V. et al. Efficient tumor targeting by single-domain antibody fragments of camels. Int. J. Cancer 98, 456–462 (2002).

    Article  CAS  Google Scholar 

  30. Conrath, K. et al. Antigen binding and solubility effects upon the veneering of a camel VHH in framework-2 to mimic a VH. J. Mol. Biol. 350, 112–125 (2005).

    Article  CAS  Google Scholar 

Download references

Acknowledgements

We thank A. Beschin for comments on the manuscript and V. Flamand for measurement of AST values. This work was supported by grants from the Foundation for Scientific Research-Flanders (FWO-Vlaanderen) performed in frame of an Interuniversity Attraction Poles Program – Belgian Science Policy, by the Vrije Universiteit Brussel–Research grants (Geconcerteerde Onderzoekers Acite and Onderzoeksraad). S.M. is postdoctoral fellow for FWO-Vlaanderen and B.V. is Research Fellow at the Belgian FNRS.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Toya Nath Baral.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Fig. 1

Analysis of trypanosomes that reappeared at day 60 in mice receiving two doses of NbAn33–Tr-apoL-I around the second peak of parasitemia. (PDF 292 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Baral, T., Magez, S., Stijlemans, B. et al. Experimental therapy of African trypanosomiasis with a nanobody-conjugated human trypanolytic factor. Nat Med 12, 580–584 (2006). https://doi.org/10.1038/nm1395

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nm1395

This article is cited by

Search

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