CHAPTER 17: ADAPTIVE IMMUNITY Flashcards
Q: What are cytokines?
A: Proteins that regulate immune responses. Types include interleukins, chemokines, interferons, and tumor necrosis factor (TNF).
Q: What is an antigen, and how does it differ from an epitope?
A: Antigen: A substance that triggers an immune response. Epitope: Specific part of the antigen recognized by antibodies.
Q: What is the structure of an antibody?
A: Y-shaped molecule with two antigen-binding sites (variable regions) and a constant region.
Q: What are the 5 classes of antibodies and their main functions?
A:
* IgM: First antibody produced in an immune response.
* IgG: Main antibody in circulation; provides long-term immunity.
* IgA: Found in mucosal areas and secretions (e.g., saliva).
* IgE: Involved in allergic responses and parasitic infections.
* IgD: Role in activating B cells.
Q: How does a B cell become activated?
A: By binding an antigen and receiving signals from a helper T cell.
Q: What are the differences between naïve B cells, memory B cells, and plasma B cells?
A:
* Naïve B cell: Has not encountered an antigen.
* Memory B cell: Retains information about an antigen for quicker future responses.
* Plasma B cell: Produces and secretes antibodies.
Q: What is clonal selection?
A: The process where specific B or T cells are activated and proliferate after encountering an antigen.
Q: How do antibodies help fight infections?
A:
1. Agglutination: Clumps pathogens together.
2. Opsonization: Marks pathogens for phagocytosis.
3. Antibody-dependent cell-mediated cytotoxicity: Activates immune cells to kill pathogens.
4. Neutralization: Blocks pathogen binding to host cells.
5. Complement activation: Triggers complement-mediated lysis.
Q: What are antigen-presenting cells (APCs), and what do they do?
A: APCs (e.g., macrophages, dendritic cells) present antigens on MHCII molecules to activate T cells
Q: What is the function of helper T cells and cytotoxic T cells?
A:
* Helper T cells: Activate B cells and cytotoxic T cells.
* Cytotoxic T cells: Kill infected or abnormal cells.
Q: What do natural killer (NK) cells target?
A: Virus-infected cells and cancerous cells.
Q: Compare primary and secondary immune responses to an antigen.
A: Primary response is slower and weaker; secondary response is faster and stronger due to memory cells.
Q: What are the 4 types of adaptive immunity?
A:
1. Natural active: Infection.
2. Natural passive: Maternal antibodies.
3. Artificial active: Vaccination.
4. Artificial passive: Antibody injection.
