Related Experiment Video
Updated: Aug 14, 2026
09:45
Detection of Trypanosoma brucei Variant Surface Glycoprotein Switching by Magnetic Activated Cell Sorting and Flow Cytometry
Published on: October 19, 2016
Antigenic variation in trypanosomes: enhanced phenotypic variation in a eukaryotic parasite
1Wellcome Centre for Molecular Parasitology, University of Glasgow, Scotland, UK.
Advances in Parasitology
|July 20, 2001
Summary
African trypanosomes evade host immunity by switching their surface coat protein, variant surface glycoprotein (VSG). This antigenic variation involves complex gene regulation and recombination, aiding parasite survival and transmission.
Area of Science:
- Parasitology
- Immunology
- Molecular Biology
Background:
- African trypanosomes are extracellular parasites causing disease in mammals.
- They possess a surface coat of variant surface glycoprotein (VSG) essential for immune evasion.
- Antigenic variation, the switching of VSG expression, is a key survival strategy.
Purpose of the Study:
- To elucidate the mechanisms and evolutionary significance of VSG antigenic variation in African trypanosomes.
- To understand the population dynamics and hierarchical expression of VSG variants within hosts.
- To investigate the role of VSG expression in parasite transmission and adaptation.
Main Methods:
- Analysis of VSG gene repertoire and expression sites (BESs).
- Study of DNA recombination mechanisms for VSG switching.
- Investigation of transcriptional regulation in bloodstream and metacyclic stages.
Main Results:
- Trypanosomes express a single VSG at a time, switching through transcriptional control and DNA recombination.
- Antigenic variation is linked to parasite population dynamics and hierarchical expression.
- Metacyclic trypanosomes in tsetse flies express a defined VSG mixture for enhanced transmission.
Conclusions:
- Antigenic variation is a sophisticated survival strategy involving a vast VSG gene repertoire and regulated expression.
- VSG switching enhances parasite persistence, transmission, and adaptation to host immunity.
- Further research on the metacyclic stage is needed to fully understand VSG differential expression.
More Related Videos
Related Concept Videos
02:32Position-effect Variegation
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
01:25Genetic Variation
Genetic variation is the diversity in DNA sequences found among individuals of the same species. This diversity is crucial for a species' survival because it helps organisms adapt to environmental changes. Genetic variation begins with fertilization, where an egg and sperm cell merge. Each of these cells carries 23 chromosomes, up to 46 in the fertilized egg. Chromosomes are long DNA strands that contain genes, the basic units of heredity.
Genes exist in different versions called alleles, which...
Genes exist in different versions called alleles, which...
01:27Diversity 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...
01:29Malaria
Malaria pathogenesis in humans reflects a delicate interplay between parasite biology and host response. Clinical illness reflects a host’s immune response to the parasite’s asexual replication cycle, which is often asymptomatic in individuals with partial immunity. From the parasite's perspective, transmission between mosquito and human with minimal host pathology is evolutionarily advantageous. Among the six Plasmodium species infecting humans, P. falciparum and P. vivax dominate in global...
01:22American Trypanosomiasis
Chagas disease, or American trypanosomiasis, is a vector-borne parasitic infection caused by Trypanosoma cruzi, a flagellated protozoan (kinetoplastid) of the family Trypanosomatidae. The disease is endemic in Latin America, although cases are increasingly reported worldwide due to human migration. Transmission most commonly occurs when feces of infected triatomine bugs contaminate bite wounds or mucosal surfaces; additional routes include congenital, transfusional, transplant-related, and oral...
01:21Antiprotozoal 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...