Textbook Question
Propose a hypothesis to explain how self-reactive B cells are identified and eliminated during maturation.
Ch. 48 - The Immune System in Animals
Freeman8th EditionBiological ScienceISBN: 9780138276263
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Table of contents
- Ch. 1 - Biology: The Study of Life13
- Ch. 2 - Water and Carbon: The Chemical Basis of Life14
- Ch.3 - Protein Structure and Function10
- Ch.4 - Nucleic Acids and the RNA World10
- Ch. 5 - An Introduction to Carbohydrates10
- Ch. 6 - Lipids, Membranes, and the First Cells11
- Ch. 7 - Inside the Cell10
- Ch. 8 - Energy and Enzymes: An Introduction to Metabolism10
- Ch. 9 - Cellular Respiration and Fermentation11
- Ch. 10 - Photosynthesis12
- Ch. 11 - Cell-Cell Interactions12
- Ch. 12 - The Cell Cycle8
- Ch. 13 - Meiosis12
- Ch. 14 - Mendel and the Gene23
- Ch. 15 - DNA and the Gene: Synthesis and Repair15
- Ch. 16 - How Genes Work16
- Ch. 17 - Transcription, RNA Processing, and Translation16
- Ch. 18 - Control of Gene Expression in Bacteria16
- Ch. 19 - Control of Gene Expression in Eukaryotes12
- Ch. 20 - The Molecular Revolution: Biotechnology, Genomics, and New Frontiers15
- Ch. 21 - Genes, Development, and Evolution12
- Ch. 22 - Evolution by Natural Selection16
- Ch. 23 - Evolutionary Processes13
- Ch. 24 - Speciation15
- Ch. 25 - Phylogenies and the History of Life13
- Ch. 26 - Bacteria and Archaea15
- Ch. 27 - Diversification of Eukaryotes16
- Ch. 28 - Green Algae and Land Plants16
- Ch. 29 - Fungi18
- Ch. 30 - An Introduction to Animals9
- Ch. 31 - Protostome Animals15
- Ch. 32 - Deuterostome Animals17
- Ch. 33 - Viruses16
- Ch. 34 - Plant Form and Function16
- Ch. 35 - Water and Sugar Transport in Plants16
- Ch. 36 - Plant Nutrition13
- Ch. 37 - Plant Sensory Systems, Signals, and Responses16
- Ch. 38 - Flowering Plant Reproduction and Development16
- Ch. 39 - Animal Form and Function17
- Ch. 40 - Water and Electrolyte Balance in Animals16
- Ch. 41 - Animal Nutrition16
- Ch. 42 - Gas Exchange and Circulation16
- Ch. 43 - Animal Nervous Systems16
- Ch. 44 - Animal Sensory Systems16
- Ch. 45 - Animal Movement11
- Ch. 46 - Chemical Signals in Animals16
- Ch. 47 - Animal Reproduction and Development16
- Ch. 48 - The Immune System in Animals16
- Ch. 49 - An Introduction to Ecology15
- Ch. 50 - Behavioral Ecology16
- Ch. 51 - Population Ecology16
- Ch. 52 - Community Ecology20
- Ch. 53 - Ecosystems and Global Ecology17
- Ch. 54 - Biodiversity and Conservation Ecology18
Chapter 48, Problem 12
Self-amplifying RNA vaccines currently being developed are typically derived from alphaviruses—Class IV, positive-sense, single-stranded RNA viruses. Explain why an alphavirus is a good choice.
Verified step by step guidance1
Understand the nature of alphaviruses: Alphaviruses are Class IV viruses according to the Baltimore classification system, which means they have a positive-sense, single-stranded RNA genome. This type of RNA can be directly translated into proteins by the host cell's ribosomes, which is crucial for the vaccine's mechanism.
Recognize the self-amplifying characteristic: The RNA from alphaviruses not only codes for the viral proteins but also includes regions that allow the RNA to replicate itself within the host cells. This amplification means that even a small amount of initial RNA can produce a significant amount of antigen, enhancing the immune response.
Consider the safety profile: Alphavirus-based vectors are typically engineered to be replication-deficient, which means they can express the antigenic proteins but cannot produce new virus particles. This makes them safer as vaccines, reducing the risk of causing disease.
Evaluate the immune response: Alphaviruses naturally induce strong immune responses, which is beneficial for a vaccine. The immune system recognizes the viral proteins produced by the alphavirus RNA, leading to both humoral and cellular immune responses, which are important for effective vaccination.
Assess the ease of production and scalability: Using an alphavirus as a vector in RNA vaccines can be advantageous because the technology allows for rapid and relatively low-cost production compared to traditional vaccine methods. This is particularly important in responding quickly to emerging infectious diseases.
Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Alphaviruses
Alphaviruses are a group of positive-sense, single-stranded RNA viruses that belong to the Togaviridae family. They are known for their ability to replicate efficiently within host cells, making them suitable candidates for vaccine development. Their relatively simple genome structure allows for easy manipulation, which is advantageous in designing self-amplifying RNA vaccines.
Positive-sense RNA
Positive-sense RNA viruses have genomes that can be directly translated into proteins by the host's ribosomes. This characteristic allows for rapid production of viral proteins and facilitates a quick immune response when used in vaccines. The ability to use the host's cellular machinery for replication enhances the effectiveness of RNA vaccines derived from these viruses.
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Positive Feedback
Self-amplifying RNA vaccines
Self-amplifying RNA vaccines are designed to replicate within the host after administration, leading to increased expression of the target antigen. This amplification can enhance the immune response, as more antigen is produced, potentially resulting in a stronger and longer-lasting immunity. The use of alphaviruses in these vaccines leverages their natural replication capabilities to improve vaccine efficacy.
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Related Practice
Textbook Question
Which of the following outcomes would be expected if somatic hypermutation did not occur?
a. The diversity of pattern-recognition receptors would be significantly lowered.
b. B and T lymphocytes would not be able to produce receptors that recognize antigens.
c. The adaptive immune response would not be activated by pathogens.
d. The secondary immune response to a repeat infection would produce the same antibodies as those made in the primary immune response.
Textbook Question
What are two main criteria required for an RNA vaccine to be effective at protecting a vaccinated individual from a viral infection?