Immunology Flashcards
What is the goal of the immune system?
Identify and eliminate microorganisms and harmful substances
What is an example of Protozoa?
Amoeba
How does the skin prevent infection?
- Physical barrier (tightly packed keratinised cells)
- Physiological factors (low pH, low oxygen tension)
- Sebaceous glands (hydrophobic oils, lysozyme, ammonia, antimicrobials)
How does mucous prevent infection?
- Physical barrier
- Secrete IgA
- Enzymes
- Cilia
What are the key features of the immune system?
- Specifically identify and respond
- Modify response
- Promote tissue repair
- Memory
What are examples of phagocytes?
Neutrophils
Monocytes
Macrophages
Dendritic cells
What are examples of lymphocytes?
T cells
B cells
NK cells
What does complement do?
Initiate inflammation
What do mast cells protect?
Mucosal surfaces
Where are basophils and eosinophils recruited to?
Sites of inflammation
What chemicals do mast cells, basophils and eosinophils make?
Histamine, heparin, cytokines
What are macrophages, neutrophils and dendritic cells?
Phagocytic cells
- Ingest bacteria
- Clear debris
- Source of cytokines
Where are neutrophils recruited to?
Inflamed and infected tissues
Functions of monocytes and macrophages?
Limit inflammation
Tissue repair
Antigen presentation
Action of dendritic cells
Immature in peripheries
Mature into secondary lymphoid tissues
Antigen presentation
Function of NK cells
Kill tumour cells
Kill virally infected cells
When do T and B cells activate?
When they meet a pathogen/antigen
Main function of B cells
Produce antibodies
Main function of T cells
Defence against intracellular pathogens
Types of T cells
Helper T cells
- Regulate immunity
Cytotoxic T cells
- Kill virally infected cells
Examples of primary lymphoid tissues and their functions
Bone marrow and thymus
Leukocyte development
Examples of secondary lymphoid tissues and their functions
Spleen, LNs, adenoid, tonsils
Adaptive responses initiated
What are the two mechanisms of immune system communication?
- Direct contact
2. Indirect
What interactions occurs in direct contact?
Receptor:Ligand
How does indirect communication occur?
Injured and activated cells produce cytokines
Examples and actions of cytokines
Interferons (anti viral)
TNF (pro inflammatory)
Chemokines (cell migration)
Interleukins (IL-2 T cell proliferation, IL-10 anti inflammatory)
Symptoms of inflammation
Rubor (redness) Calor (heat) Tumor (swelling) Donor (pain) Loss of function Fever
What are the stages of the immune response?
- Recognition phase
- Activation phase
- Effector phase
What is involved in the recognition phase?
Pattern recognition receptors-Pathogen associated molecular patterns
How do mast cells respond to infection?
- Degranulation - Histamine and tryptase
2. Gene expression - TNF, Chemokines, Leukotrienes
What do pro-inflammatory mediators do?
Increase vascular permeability
Dilate post-capillary venues
Activate endothelium
Process of transendothelial migration
- Tethering via selectins and ICAMs
- Rolling
- Activation
- Firm adhesion via integrins
- Flattening
- Migration
What is the function of interferon gamma?
Enhances macrophage killing
C6, C7, C8, C9 and C5b form the…
…Membrane Attack Complex (osmotic cell lysis)
What cells are MHC Class 1 proteins expressed on?
All nucleated cells
What cells are Class 2 MHC proteins expressed on?
Professional antigen presenting cells (dendritic cells and macrophages and B cells)
What antibodies are provided by a mother to her child?
IgG across placenta
Dimeric IgA in breastmilk
What are important opsonins?
C3b
C4b
CRP
What cells assist B cells in antibody class switching?
CD4 T Lymphocytes
