Related Experiment Video

Updated: Aug 20, 2026

Investigating the Phagocytosis of Leishmania using Confocal Microscopy
08:41

Investigating the Phagocytosis of Leishmania using Confocal Microscopy

Published on: July 29, 2021

Cutting edge: neutrophil granulocyte serves as a vector for Leishmania entry into macrophages

Ger van Zandbergen1, Matthias Klinger, Antje Mueller

  • 1Institute for Medical Microbiology and Hygiene, University of Lübeck, Lübeck, Germany. Zandbergen@hygiene.ukl.mu-luebeck.de

Journal of Immunology (Baltimore, Md. : 1950)
|November 24, 2004
PubMed

Insights

Leishmania parasites infect neutrophils (PMN), delaying their death and causing them to attract macrophages (MF). Macrophages then ingest these infected neutrophils, allowing Leishmania to enter and multiply within them.

Area of Science:

  • Immunology
  • Parasitology
  • Cell Biology

Background:

  • Macrophages (MF) are the primary host cells for Leishmania major (L. major) replication.
  • Polymorphonuclear neutrophil granulocytes (PMN) are the initial leukocytes at infection sites, encountering L. major before MF.
  • Previous research showed PMN phagocytose but do not eliminate L. major, with infected PMN apoptosis delayed for 2 days.

Purpose of the Study:

  • To investigate if macrophages can ingest Leishmania-infected neutrophils.
  • To understand the mechanism by which Leishmania utilizes PMN for host cell entry.

Main Methods:

  • Co-culture of Leishmania-infected neutrophils with macrophages.
  • Observation of phagocytosis of infected neutrophils by macrophages.
  • Analysis of Leishmania survival and multiplication within macrophages.
  • Measurement of cytokine release (TGF-beta) from macrophages post-phagocytosis.

Main Results:

  • Macrophages readily phagocytosed Leishmania-infected apoptotic neutrophils.
  • Leishmania survived and multiplied within macrophages after indirect internalization via neutrophils.
  • Ingestion of infected neutrophils by macrophages induced the release of the anti-inflammatory cytokine TGF-beta.

Conclusions:

  • Leishmania major exploits neutrophils as a "Trojan horse" to facilitate entry into macrophages.
  • This mechanism allows Leishmania to enter its final host cells undetected.
  • The process involves delayed neutrophil apoptosis, chemokine secretion, and subsequent macrophage phagocytosis.

More Related Videos

Quantification of Intracellular Growth Inside Macrophages is a Fast and Reliable Method for Assessing the Virulence of Leishmania Parasites10:01

Quantification of Intracellular Growth Inside Macrophages is a Fast and Reliable Method for Assessing the Virulence of Leishmania Parasites

Published on: March 16, 2018

Related Concept Videos

Leishmaniasis01:30

Leishmaniasis

Leishmaniasis is a protozoal disease caused by species of the genus Leishmania and transmitted through the bite of infected female sandflies. The parasite exists in two principal morphological forms during its life cycle. A sandfly acquires intracellular amastigotes from an infected reservoir host, such as a dog. Within the sandfly, these forms differentiate into motile, flagellated promastigotes. During a subsequent blood meal, promastigotes are injected into the human host, where they...
Differentiation of Common Myeloid Progenitor Cells01:15

Differentiation of Common Myeloid Progenitor Cells

Common myeloid progenitors (CMPs) are oligopotent cells that can differentiate into granulocytes and macrophages. Granulocytes and macrophages are essential for protecting the body against bacterial, viral, or fungal infections. They migrate from the bone marrow into the circulating blood to reach specific tissue sites where they differentiate and help in immune surveillance. However, they survive only for a few days and must be continuously made available to the organism to maintain a robust...
Antiprotozoal Agents01:21

Antiprotozoal Agents

Leishmaniasis is a widespread parasitic disease caused by several Leishmania species. It affects millions of people each year and remains a major public health problem in endemic regions. First-line treatment relies on pentavalent antimonials, including meglumine antimoniate and sodium stibogluconate. Even so, how these drugs work has not been fully clear, especially their interaction with parasite-specific biochemical pathways. One key target is trypanothione reductase (TR), an enzyme that...