Immune system Flashcards
What are the two immunities that make up the immune system?
Innate immunity and adaptive immunity
What does the innate immune system do?
Provides the body’s first line of defense against infectious agents
What defensive barriers are involved in the innate immunity?
Anatomic and physical Physiologic Complement Cellular Inflammation
Give examples of anatomic and physical barriers of the innate immunity.
Examples: skin, mucus membranes and normal flora
Give examples of physiologic barriers in the innate immunity.
Examples: temperature, pH, anti-microbials and cytokines
Give examples of cellular defenses in the innate immunity.
Examples: phagocytes and granulocytes
What characteristics do the innate immune defenses have in common?
- Present intrinsically with or without previous stimulation
- Have limited specificity for shared microbe and cellular structure (pathogenic associated molecular patterns [PAMPs] and damage-associated molecular patterns [DAMPs]
- Have limited diversity as reflected by a limited number of pattern recognition receptors
- Are not enhanced in activity upon subsequent exposure- no memory
What are the components of the adaptive immune response?
B and T lymphocytes and their effector cells
What produces the heavy chain variable domains?
VDJ recombination
What produces the light chain variable domains?
VJ recombination
What gene is required for making the enzyme that is required to make the VJ recomination?
Rag1 and Rag2
What does terminal deoxyribonucleotidy transferase (Tdt) do?
Randomly inserts bases on the heavy chain while it is undergoing recombination. Not active during light chain recombination in B cells.
Active during the rearrangement of all gene segments in the formation of the TCR
What do T lymphoctes bind on their TCR?
Peptides and only peptides
What does the inflammasome secrete when it is activated?
Produces IL-1-beta and IL-18
Characteristics of Neutrophils
- Circulating phagocytes
2.Short lived - Rapid response, not prolonged defense
These are the first to arrive
Characteristics of Monocytes/Macrophages
- Monocytes circulate in the blood, become macrophages in the tissues
- Provide a prolonged defense
- Produces cytokines that initiate and regulate inflammation
- Phagocytose pathogens
- Clear dead tissue and initiate tissue repair
- Macrophages will develop along one of 2 different pathways
Characteristics of Dendritic cells (DCs)
- Found in all tissues
- Antigen processing and presentation (APC)
- Two major functions: initiate inflammatory response and stimulate adaptive immune response
Characteristics of Mast cells
- Found in the skin and mucosa
2. Two pathways for activation: innate TLRs and antibody-dependent (IgE)
Characteristics of Natural killer cells (NK cells)
- Found in the blood and periphery
- Direct lysis of cells
- Secretes IFN-gamma
What is chemotaxis and who does it?
Chemotaxis:
Recruitment of inflammatory cells and anaphylatoxins
Complement proteins:
C3a, C4a, and C5a
What is opsonization of pathogens do and who does that?
Opsonization of pathogens makes it easier for them to be phagocytosed and killed
Complement protein:
C3b
How does the complement system kill pathogens and who does that?
Puts holes in the membrane
Done by membrane attack complex (MAC) which is made up of C5b, C6, C7, C8, and C9
What is the alternative pathway for activating the complement pathway?
Lectin-binding or mannose-binding pathway (MBP)
Mannose-binding leptin binds to carbohydrates on the pathogen. Activates C3 of the complement pathway
Part of innate immunity.
What are the 4 steps of the acute inflammatory response?
Step 1: Rolling
Step 2: Activation by chemo-attractants
Step 3: Arrest and adhesion
Step 4: Transendothelial migration (extravasation)
