The Immune System Flashcards
How is innate (non-specific) immunity activated?
- Cells can distinguish non-self pathogens
- Pathogens have pathogen-associated molecular patterns (PAMPs)
- Immune cells have toll-like receptors (TLR)
- TLR bind to PAMPs
- Repeated exposure produces memory cells
Describe immunological surveillance
-
Natural killer cells (NK)
- Identify and attach to abnormal cells
-
Golgi apparatus moves toward abnormal cell
- Exocytosis of secretory vesicles containing perforins
- Perforins lyse abnormal plasma membrane
What are interferons?
- Type of cytokine (immune system hormone)
- Released by lymphocytes and macrophages
- Slows viral infection
1. Signals uninfected cells to destroy RNA and reduce protein synthesis
2. Signals infected cells to do apoptosis
3. Activates immune cells
What are the three types of interferons?
ALPHA
- Produced by infected cells
- Attract and stimulate NK
- Enhance resistance
BETA
- Produced by fibroblasts
- Slows inflammation
GAMMA
- Produced by T cells and NK
- Stimulates macrophages
Classical activation pathway VS Alternative activation pathway
CLASSICAL
C1 (enzyme)
- attaches to two antibodies
- produces C2a/b, C4a/b
C2a+C4b (enzyme)
- splits C3 to produce C3a/b
ALTERNATIVE
- No Antibody involvement
- Occurs more slowly and less effective
- Activated by exposure to foreign materials
What are the effects of inflammation?
- Localized response
- Temporary barrier against pathogens
- Slows spread of pathogens
- Mobilize defenses
- Facilitates repairs
Describe the three products of inflammation
NECROSIS
- Destroy injured cells
PUS
- Viscous fluid mixture
- Accumulated debris, fluid, dead cells
ABSCESS
- Accumulated pus
- In enclosed tissue space
Active VS Passive Immunity
ACTIVE
- Antibodies develop after exposure
- Naturally acquired via environment
- Artificially acquired via pathogen-containing vaccines
PASSIVE
- Antibodies transferred
- Naturally acquired from mother
- Artificially acquired by injected antibodies
What are the four types of T cells?
CYTOTOXIC
- Attack virus-infected cells
- Cell-mediated immunity
MEMORY
- Clone in response to “remembered” antigens
HELPER
- Stimulates T cells and B cells
SUPPRESSOR
- Inhibit T cells and B cells
Describe Class I MHC proteins
- Found in membranes of all nucleated cells
- Upon infection
- Carries small peptides to surface
- T cells activated by abnormal peptides
- Invitation to be destroyed
Describe Class II MHC proteins
- Phagocytic antigen-presenting cells engulf extracellular pathogens
- Antigenic fragments produced
- Bind and displayed by class II MHC
- Stimulates T cells
What is an antigen?
- Causes immune system to produce antibodies
- Eg bacteria/virus/pollen
- Or molecular structures on the surface
Innate VS Adaptive Immunity
INNATE
- Non-specific
- Works the same way
- Against all invading agents
ADAPTIVE
- Specific
- Depends on lymphocytes activities
- Develops after exposure
What are the seven major categories of innate immunity?
PHYSICAL BARRIER
- Skin outer layer, hair, secretions
PHAGOCYTES
- Attack and remove pathogens
IMMUNE SURVEILLANCE
- NK cells monitor normal tissues
INTERFERONS
- Chemical messengers
- Anti-viral proteins
- Block replication
COMPLEMENT
- Circulating proteins
- Cascade
- Assists antibodies
INFLAMMATION
- Localized, tissue-level
- Limit spread of injury
FEVER
- Increases body metabolism
- Accelerates defenses
Microphages VS Macrophages
MICROPHAGES
- Neutrophils and eosinophils
- Leave bloodstream
- Enter peripheral tissues
MACROPHAGES
- Large phagocytic cells
- From monocytes
