Related Experiment Video

Updated: Aug 31, 2026

Forward Genetic Approaches in Chlamydia trachomatis
09:03

Forward Genetic Approaches in Chlamydia trachomatis

Published on: October 23, 2013

Parachlamydia acanthamoebae enters and multiplies within human macrophages and induces their apoptosis [corrected]

Gilbert Greub1, Jean-Louis Mege, Didier Raoult

  • 1Unité des Rickettsies, Faculté de Médecine, Université de la Méditerranée, 27 boulevard Jean Moulin, 13385 Marseille, France.

Infection and Immunity
|September 23, 2003
PubMed

Insights

Parachlamydia acanthamoebae infects human macrophages, multiplying within them and causing cell death via apoptosis. This obligate intracellular bacterium shows potential as a human pathogen.

Area of Science:

  • Microbiology
  • Cell Biology
  • Immunology

Background:

  • Parachlamydia acanthamoebae is an obligate intracellular bacterium.
  • It naturally infects amoebae and is a potential human pathogen.
  • It may survive and replicate within human macrophages.

Purpose of the Study:

  • To investigate the interaction of P. acanthamoebae with human monocyte-derived macrophages.
  • To determine if P. acanthamoebae can enter, multiply, and survive within macrophages.
  • To assess the effect of P. acanthamoebae infection on macrophage viability.

Main Methods:

  • Infection of human monocyte-derived macrophages with P. acanthamoebae.
  • Quantification of intracellular bacteria using microscopy and qPCR.
  • Detection of bacterial transcriptional activity using RT-PCR.
  • Assessment of macrophage apoptosis using annexin-V binding and electron microscopy.

Main Results:

  • P. acanthamoebae efficiently infected macrophages, with 80% infected within 8 hours.
  • Intracellular bacterial numbers increased fourfold within 4 days, indicating replication.
  • Bacterial transcriptional activity was confirmed.
  • Macrophage numbers decreased significantly due to apoptosis following infection with live bacteria.

Conclusions:

  • P. acanthamoebae successfully enters and replicates within human macrophages.
  • The bacterium induces apoptosis in infected macrophages, demonstrating a cytopathic effect.
  • These findings highlight P. acanthamoebae's potential as a human pathogen.

More Related Videos

Experimental Analysis of Apoptotic Thymocyte Engulfment by Macrophages06:47

Experimental Analysis of Apoptotic Thymocyte Engulfment by Macrophages

Published on: May 24, 2019

Using Fluorescent Proteins to Visualize and Quantitate Chlamydia Vacuole Growth Dynamics in Living Cells07:42

Using Fluorescent Proteins to Visualize and Quantitate Chlamydia Vacuole Growth Dynamics in Living Cells

Published on: October 13, 2015

Related Concept Videos

Bacterial Phylum Chlamydiae01:29

Bacterial Phylum Chlamydiae

The phylum Chlamydiae or Chlamydiota is composed of a single order, Chlamydiales. This phylum consists entirely of obligate intracellular parasites that infect eukaryotic hosts. While human pathogens within this group have been studied extensively, the phylum encompasses many species capable of interacting with various eukaryotic organisms. Members of Chlamydiae are typically small cocci, approximately 0.5 μm in diameter, and exhibit a distinctive developmental cycle. As is characteristic of...
Trichomoniasis01:18

Trichomoniasis

Trichomonas vaginalis is a flagellated protozoan parasite and the causative agent of trichomoniasis, one of the most prevalent non-viral sexually transmitted infections in the United States. This extracellular parasite primarily colonizes the lower genitourinary tract in women—particularly the vagina—and in men, the urethra and prostate. Its structural and functional adaptations enable its survival, motility, and pathogenicity within the host environment.Structural Features and Host EntryT.
Phagocytosis of Apoptotic Cells01:17

Phagocytosis of Apoptotic Cells

Cells undergoing apoptosis form apoptotic bodies that must be removed immediately to prevent inflammation, autoimmune diseases, and necrosis. Phagocytosis is carried out by professional phagocytes such as macrophages or  immature dendritic cells. Non-professional phagocytes such as  epithelial cells and fibroblasts also take part in this process; however, they are not as effective as professional phagocytes. 
Normal cells contain receptors that prevent them from being recognized by phagocytes.
Amebiasis01:28

Amebiasis

Entamoeba histolytica, a protozoan parasite, is responsible for intestinal and extraintestinal amebiasis. Though a significant proportion of infections remain asymptomatic, approximately 50 million individuals annually are estimated to present with clinical disease, resulting in up to 100,000 deaths globally. The disease burden is disproportionately high in regions with lower socioeconomic status, such as parts of India, Africa, Mexico, and Latin America.Etiology and TransmissionThe infective...
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...
Fungal Phylum Microsporidia01:28

Fungal Phylum Microsporidia

Microsporidia are a group of obligate intracellular fungi that were initially classified as protists but were later reclassified based on phylogenetic, molecular, and structural evidence linking them to the Chytridiomycota. These unicellular, non-motile organisms are highly specialized parasites that infect a wide range of animal hosts, including humans. They have evolved extensive genomic and metabolic reductions, making them highly dependent on their hosts for survival.Morphology and Genomic...