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Questions and Answers
Which immunoglobulin class is specifically produced against helminths?
Which immunoglobulin class is specifically produced against helminths?
What is a major consequence of the immune response mechanisms activated against helminths?
What is a major consequence of the immune response mechanisms activated against helminths?
What role do eosinophils play in the immune response to helminths?
What role do eosinophils play in the immune response to helminths?
According to the hygiene hypothesis, why are allergies and autoimmune diseases more common in developed countries?
According to the hygiene hypothesis, why are allergies and autoimmune diseases more common in developed countries?
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What mechanisms have helminths evolved to prevent strong immune responses?
What mechanisms have helminths evolved to prevent strong immune responses?
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In developing strategies for worm therapy, what aspect of helminths is most exploited?
In developing strategies for worm therapy, what aspect of helminths is most exploited?
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Why are complement proteins less effective against helminths?
Why are complement proteins less effective against helminths?
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Which type of parasite is specifically categorized as a macro-organism?
Which type of parasite is specifically categorized as a macro-organism?
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What mechanism allows African trypanosomes to evade the host immune system?
What mechanism allows African trypanosomes to evade the host immune system?
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Which gene expression mechanism is primarily responsible for antigenic variation in T. brucei?
Which gene expression mechanism is primarily responsible for antigenic variation in T. brucei?
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Which of the following parasites is known for its immunosuppressive effects?
Which of the following parasites is known for its immunosuppressive effects?
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How do helminths potentially modulate the human immune system?
How do helminths potentially modulate the human immune system?
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Which of the following is NOT a mechanism of immune evasion used by parasites?
Which of the following is NOT a mechanism of immune evasion used by parasites?
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African trypanosomiasis is primarily transmitted by which vector?
African trypanosomiasis is primarily transmitted by which vector?
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In parasitic infections, what role does IgE typically play?
In parasitic infections, what role does IgE typically play?
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What is a potential therapeutic route for exploiting parasitic immune modulation?
What is a potential therapeutic route for exploiting parasitic immune modulation?
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How do African trypanosomes evade the immune response?
How do African trypanosomes evade the immune response?
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What role do IgE and eosinophils play in the immune response to parasitic helminths?
What role do IgE and eosinophils play in the immune response to parasitic helminths?
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Why cannot protein ES-62 be used therapeutically despite its anti-inflammatory properties?
Why cannot protein ES-62 be used therapeutically despite its anti-inflammatory properties?
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What has been the observed effect of reduced infection rates with parasitic worms?
What has been the observed effect of reduced infection rates with parasitic worms?
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What is the significance of VSG gene expression in African trypanosomes?
What is the significance of VSG gene expression in African trypanosomes?
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What therapeutic approach is being explored to utilize the effects of protein ES-62?
What therapeutic approach is being explored to utilize the effects of protein ES-62?
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What is the primary immune mechanism involved in response to parasitic infections as described in the content?
What is the primary immune mechanism involved in response to parasitic infections as described in the content?
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What can be inferred about the relationship between parasitic worm infections and allergic diseases?
What can be inferred about the relationship between parasitic worm infections and allergic diseases?
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Study Notes
Parasites and the Immune System
- Parasites evade the mammalian immune system in various ways
- African trypanosomes employ antigenic variation to outwit the host's antibody responses
- IgE-mediated responses target parasitic helminths, modulating the host immune system
- Different organisms evolved various ways to circumvent the immune system
- Parasites may evade destruction by residing in hard-to-reach locations or expressing different surface antigens
Avoidance of Destruction by the Immune System
- Location: Some parasites, like Plasmodium and Leishmania, reside intracellularly within host cells (liver cells, macrophages, etc.)
- Cysts: Other parasites, such as Toxoplasma and Echinococcus, form cysts to evade destruction
- Antigenic Mimicry: Some parasites mimic host antigens to avoid detection
- Immunosuppression: Certain parasites, like T. cruzi, T. brucei, and filarial worms, suppress the host immune system
- Antigenic Variation: Parasites like T. brucei, Borrelia, and Neisseria employ antigenic variation, changing surface antigens to evade detection
Antigenic Variation in African Trypanosomes
- African trypanosomes have over 1,000 genes that code for different coat proteins
- These coat proteins are sequentially expressed
- This variation allows a parasite to constantly change the antigens that it expresses, thereby constantly outpacing the host immune system
Human African Trypanosomiasis
- A disease caused by trypanosomes
- This disease is shown in a picture of a sick man in bed being watched by a woman
T. brucei Lifecycle
- Tsetse fly transmits parasites into a mammal's bloodstream
- The parasite exists in two forms in the mammalian host: short and stumpy, and long and slender
- The parasite has two life cycle stages inside the tsetse fly (procyclic and metacyclic trypomastigotes)
VSG Transcription
- The surface glycoprotein (VSG) is vital for the parasite’s survival
- VSGs are transcribed in only one allele (VSG gene) at a time
Successive Waves of Parasitaemia
- A graph illustrating the fluctuating number of parasites over weeks post-infection
Parasite Sizes
- Infectious agents vary significantly in size, from viruses to protozoa to metazoan parasites.
Parasitic Worms and the Hygiene Hypothesis
- Immunological responses that combat "micro-organisms" are often ineffective against large "macro-organisms" like parasitic worms
- Complement proteins and antibodies aren't effective because they can’t pass through their barriers
- Specific immune responses against worms (e.g., IgE)
- Eosinophils release proteins harmful to worms
- Regulatory T cells are involved in minimizing immune damage in response to worms
Worm Therapy
- Modifying the mechanisms used by worms to modulate host immunity is a potential therapeutic strategy
- Protein ES-62, secreted by Acanthocheilonema viteae, triggers an anti-inflammatory response
- Purification and injection of ES-62 reduces inflammation, potentially treating autoimmune diseases, however, the protein itself triggers an immune response
Summary of Parasites and the Immune System
- Parasites evade the immune system
- African trypanosomes use antigenic variation
- Parasitic worms activate different immune responses
- There are potential therapeutic targets by using the worms modulation methods to manipulate the immune system for better outcomes
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Description
Explore the fascinating interactions between parasites and the mammalian immune system. This quiz examines strategies used by parasites, such as antigenic variation and location evasion, to survive and thrive within their hosts. Test your understanding of these complex biological processes.
