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Persistence without pathology in phosphoglycan-deficient Leishmania major

Gerald F Späth1, Lon-Fey Lye, Hiroaki Segawa

  • 1Department of Molecular Microbiology, Washington University Medical School, St. Louis, MO 63110, USA.

Science (New York, N.Y.)
|August 30, 2003
PubMed

Insights

Leishmania parasites lacking phosphoglycans can persist long-term in hosts without causing disease. This discovery offers a new model for studying parasite persistence and its role in Leishmania immunity.

Area of Science:

  • Parasitology
  • Immunology
  • Molecular Biology

Background:

  • Leishmania infections cause acute pathology via macrophage replication.
  • Parasite persistence after recovery can lead to severe disease upon reactivation.
  • Factors influencing Leishmania persistence are poorly understood, especially parasite-derived factors.

Purpose of the Study:

  • To investigate the role of parasite factors in Leishmania persistence and disease.
  • To characterize Leishmania major lacking phosphoglycans (lpg2-) for persistence studies.

Main Methods:

  • Generation and characterization of Leishmania major mutant lacking phosphoglycans (lpg2-).
  • Assessment of parasite survival in sand flies and macrophages.
  • Evaluation of long-term persistence in mammalian hosts.

Main Results:

  • Leishmania major lpg2- mutants were unable to survive in sand flies and macrophages.
  • Despite impaired survival in vectors and hosts, lpg2- mutants persisted indefinitely in the mammalian host.
  • The lpg2- mutant did not induce disease in the mammalian host.

Conclusions:

  • Leishmania phosphoglycans are essential for survival in sand flies and macrophages but not for long-term host persistence.
  • Leishmania major lpg2- mutants provide a valuable model for studying parasite persistence independent of acute pathology.
  • This model can be used to investigate parasite factors controlling persistence and their impact on host immunity.

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