Related Experiment Video

Updated: Jun 10, 2026

Visualizing Non-lytic Exocytosis of Cryptococcus neoformans from Macrophages Using Digital Light Microscopy
10:02

Visualizing Non-lytic Exocytosis of Cryptococcus neoformans from Macrophages Using Digital Light Microscopy

Published on: October 21, 2014

Phagocytosis of Cryptococcus neoformans by, and nonlytic exocytosis from, Acanthamoeba castellanii

Cara J Chrisman1, Mauricio Alvarez, Arturo Casadevall

  • 1Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.

Applied and Environmental Microbiology
|August 3, 2010
PubMed

Insights

The yeast Cryptococcus neoformans uses its capsule to evade amoebae, similar to how it evades macrophages. This yeast can also exit amoebae without killing them, suggesting virulence evolved from environmental interactions.

Area of Science:

  • Mycology
  • Pathogen-Host Interactions
  • Evolutionary Biology

Background:

  • Cryptococcus neoformans is a pathogenic yeast with a polysaccharide capsule, a key virulence factor.
  • Host-pathogen interactions, particularly with macrophages, are crucial during C. neoformans infections.
  • Similarities between C. neoformans interactions with macrophages and amoebae suggest virulence factors may have evolved from environmental pressures.

Purpose of the Study:

  • To investigate the interaction between Cryptococcus neoformans and the soil amoeba Acanthamoeba castellanii.
  • To determine the role of the fungal capsule in the interaction with amoebae.
  • To explore mechanisms of C. neoformans survival and egress from amoebae.

Main Methods:

  • Comparative analysis of wild-type, non-encapsulated, and complemented C. neoformans strains interacting with A. castellanii.
  • Observation of phagocytosis efficiency and fungal egress from amoebae.
  • Assessment of factors influencing cryptococcal exocytosis, including fungal viability and actin.

Main Results:

  • The C. neoformans capsule acts as an antiphagocytic factor for amoebae, with larger capsules reducing ingestion.
  • C. neoformans cells were observed to undergo nonlytic exocytosis from amoebae, a process dependent on fungal strain, viability, and actin.
  • Capsule presence inversely correlated with extrusion likelihood in certain strains, mirroring macrophage interactions.

Conclusions:

  • Nonlytic exocytosis of C. neoformans from amoebae parallels observations in macrophage interactions.
  • These findings support the hypothesis that mechanisms of fungal virulence evolved through selection by environmental predators like amoebae.

More Related Videos

Macrophage Cholesterol Depletion and Its Effect on the Phagocytosis of Cryptococcus neoformans11:07

Macrophage Cholesterol Depletion and Its Effect on the Phagocytosis of Cryptococcus neoformans

Published on: December 19, 2014

Complementary Use of Microscopic Techniques and Fluorescence Reading in Studying Cryptococcus-Amoeba Interactions10:56

Complementary Use of Microscopic Techniques and Fluorescence Reading in Studying Cryptococcus-Amoeba Interactions

Published on: June 22, 2019

Related Concept Videos

Cryptococcal Meningitis01:27

Cryptococcal Meningitis

Cryptococcal meningitis is a life-threatening opportunistic infection predominantly associated with HIV/AIDS, accounting for over 100,000 deaths annually worldwide. However, it also affects individuals with other forms of immunosuppression, including those undergoing immunosuppressive therapy, organ transplant recipients, patients with innate immunodeficiencies, and individuals with hematological disorders. The infection is caused mainly by Cryptococcus neoformans and Cryptococcus gattii,...
Phagocytosis00:41

Phagocytosis

Cells pull particles inward and engulf them in spherical vesicles in an energy-requiring process called endocytosis. Phagocytosis ("cellular eating") is one of three major types of endocytosis. Cells use phagocytosis to take in large objects, such as other cells (or their debris), bacteria, and even viruses.
The objective of phagocytosis is often destruction. Cells use phagocytosis to eliminate unwelcome visitors, like pathogens (e.g., viruses and bacteria). Many immune system cells, including...
Phagocytosis00:41

Phagocytosis

Cells pull particles inward and engulf them in spherical vesicles in an energy-requiring process called endocytosis. Phagocytosis (“cellular eating”) is one of three major types of endocytosis. Cells use phagocytosis to take in large objects—such as other cells (or their debris), bacteria, and even viruses.The objective of phagocytosis is often destruction. Cells use phagocytosis to eliminate unwelcome visitors, like pathogens (e.g., viruses and bacteria). It is perhaps unsurprising, that many...
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.
Immune Surveillance by NK Cells and Phagocytes01:25

Immune Surveillance by NK Cells and Phagocytes

Immune surveillance is an integral part of the innate immune system, involving the continuous monitoring of peripheral tissues to detect and respond to pathogens, infected cells, or cancerous cells. This surveillance is conducted primarily by natural killer (NK) cells and phagocytes, which employ distinct but complementary mechanisms to identify and eliminate threats.
Natural Killer Cells: The Fast Responders
NK cells are large granular lymphocytes found in the blood and lymphatic system. These...
Diversity of Protists II01:27

Diversity of Protists II

Alveolates are a group of organisms recognized by the presence of alveoli, which are cytoplasmic sacs located beneath the cell membrane. While their function remains uncertain, alveoli may help regulate water balance by controlling how much water enters and leaves the cell. In dinoflagellates, these structures may serve as armor plates. There are three major types of alveolates: ciliates, which move using cilia; dinoflagellates, which use flagella for movement; and apicomplexans, which are...