Immunology Basics Flashcards
Q: What are the primary roles of the immune response?
A: The immune response defends against pathogens, detects malignant cells, repairs damaged tissue, and prevents autoimmune diseases.
Q: What comprises the immune system?
A: The immune system consists of:
- molecules (like antibodies and cytokines)
- cells : phagocytes (neutrophils, macrophages etc), innate lymphocytes (natural killer cells/ NK) and exocytes (Mast cells, basophils, eosinophils) which release active mediators
Q: Where do immune cells originate?
A: Immune cells originate from hematopoietic stem cells in the bone marrow.
B cells mature in the bone marrow
T cells mature in the thymus
Q: What are key features and cells of the innate immune response?
A: Key features include rapid response, physical and chemical barriers, phagocytes (neutrophils, macrophages, dendritic cells), innate lymphocytes (NK cells), and exocytes (mast cells, basophils, eosinophils).
Q: What are cytokines and their functions?
A: Cytokines are small soluble proteins that mediate immune and inflammatory reactions. They include interleukins, tumor necrosis factors, chemokines, and interferons.
Q: What is the complement system?
A: The complement system is a proteolytic cascade of over 30 enzymes produced in the liver that circulates in the blood and becomes activated in the presence of microbes.
Q: What is phagocytosis, and which cells are involved?
A: Phagocytosis is the ingestion of particles by phagocytes (neutrophils, monocytes/ macrophages, dendritic cells) using pattern recognition receptors. It involves the formation of a phagolysosome to kill microbes.
– Ingestion of particles (>0.5 µm)
– Triggered by binding to pattern
recognition receptors (PRRs) or
phagocytosis receptors
– Membrane closes around the particle
– Internalised into phagosome
– Phagosome fuses with a lysosomephagolysosome
– Reactive oxygen species (ROS), Nitric
oxide (NO) and Lysomal enzymes kill the
microbe
Q: What are key features and cells of the adaptive immune response?
A: Key features include specificity, diversity, memory, and a slower response. Cells involved are lymphocytes (B cells and T cells).
Q: What do naïve lymphocytes require for activation?
A: Naïve lymphocytes require antigen recognition and costimulation to proliferate and become effector cells.
Q: What are the main components of the adaptive immune system?
A: The adaptive immune system includes:
1. humoral immunity (B cells producing antibodies)
2. cell-mediated immunity (T cells= cytotoxic CD8+ and helper CD4+ cells).
Q: How do B cells and T cells differ in antigen recognition?
A: B cells recognize free antigens, while T cells will have no response
T cells look for a complex on a cell surface.
CD8+ T cells:
These cells interact with peptides presented by MHC Class I molecules. If a CD8+ T cell receptor recognizes a non-self peptide on an MHC Class I molecule, it can kill the presenting cell, which is likely infected.
CD4+ T cells:
These cells interact with peptides presented by MHC Class II molecules. Recognition of a non-self peptide can lead to the activation of the CD4+ T cell, which then helps coordinate the immune response by producing cytokines, stimulating B cells to produce antibodies, and helping activate other immune cells.
Q: What is clonal selection and immunological memory?
A: Clonal selection is the process where only lymphocytes that recognize a specific pathogen are activated and multiply. Some become memory cells for faster response upon re-exposure.
Q: What are the main differences between the innate and adaptive immune systems?
A: The innate immune system provides a rapid, non-specific response, while the adaptive immune system offers a slower, highly specific response with memory capabilities.
What is epitope and antigen def
Epitope is the specific region of the antigen
that the lymphocyte receptor recognizes
Antigen: derived from “antibody generator”
but now we refer to antigens as anything
that a B cell or T cell receptor binds to:
– Proteins
– Lipids
– Polysaccharides
Cognate (associated) T and B cells recognise the same
antigen
