Lecture 12 - Effector responses against infectious agents (2) Flashcards
What do activated CD4+ T-cells become?
T-helper cells
What do activated CD8+ T-cells become?
Cytotoxic T-lymphocytes (CTLs)
How do CD8+ T-cells get activated?
- Recognition by naive T-cell
- Proliferation and differentiation of T-cell
- Active T-cells kill virus infected target cells
How do cytotoxic t-lymphocytes kill an infected cell?
Release granules upon cell-cell contact to induce apoptosis of the cell
What does the cytotoxic granules contain? [3]
- Granzymes
- Granulysin
- Perforin
True or False? All nucleated cells within the body can be targeted by CD8+ cells
True
What is the main way that T-help cells regulate immune responses?
Producing cytokines to regulated parts of the immune system
What is the main role of CD4+ Th1 cells?
Activates macrophages
How do CD4+ Th1 cells activate macrophages?
- Secrete Interferon-gamma
- CD40 ligand/CD40 interaction
What is the main role of CD4+ Th2 cells?
- They deal with large extracellular pathogens
- e.g. parasitic worms
What other functions do CD4+ Th2 cells have?
- Help B-cells produce antibody (IgE)
- Activating basophils, eosinophils, and mast cells
How do CD4+ Th17 cells regulate immune responses?
- Recruit neutrophils
- Stimulate macrophage and neutrophil production
- Induce antimicrobial peptide production
Where do antibodies come from?
B-cells
How do antibodies enhance the innate immune system? [6]
- Neutralisation
- Agglutination
- Opsinisation
- Antibody-dependent cell-mediated cytotoxicity
- Activation of complement
- Specialised resposnes
How does neutralisation work?
Antibody binds directly to the pathogen to prevent entry into a cell
How does Agglutination work?
- Antibody causes pathogens to clump together
- They are more likely to be phagocytosed
How does opsinisation work?
Antibody binds to a pathogen to allow it to be phagocytosed
How does antibody-dependent cell-mediated cytotoxicity work?
Natural killer cells mediate the death of infected cells and pathogens
How does the complement work?
Triggers the activation of classical complement cascade leading to cell lysis
How do specialised responses work?
- Mast cells, lipid mediators, and cytokines are released
- Initiates inflammatory response
