Immunology Flashcards
Lect 15 onwards
components of first line of defense
chem barriers, mech barriers and reflexes: skin, mucous membranes, secretions, normal microbiota
components of second line of defense
- Innate immune cells: macrophages, neutrophils, eosinophils, basophils, NKC, DC, Mast cells
- Antimicrobial mediators: cytokines like interferons, TNF, IL-6, Chemokines, complement cascade
- processes: phagocytosis, PRR activation (toll-like receptors), inflammation, fever
components of third line of defense
Adaptive immunity: T cells, B cells and antibodies
which lines of defense are specific vs non-specific?
non-specific: first and second line of defense
specific: third line of defense
When and what was the first vaccine attempt
15th century, smallpox crust inhaled or inserted in skin cuts (called variolation), then Jenner realized cowpox made people resistant to smallpox
what do you call it when you reduce pathogenicity of pathogen for vaccination?
attenuation
Humoral vs Cell mediated immunity
Humoral: B cells and antibodies, complement proteins and certain antimicrobial peptides
Cell-mediated: delayed, T cells and macrophages and NKC
what animal was used as model for phagocytosis via macrophages?
starfish larvae
_____ is one of the few vaccines thats efficient even after host has already been infected with pathogen.
anti-rabies
how does immunotherapy work?
blocks tumour cells from deactivating T cells
describe defensins
- small
- cysteine rich
- catatonic (positively charged)
- in plants, vertebrates and invertebrates
- disrupts cell membranes
- found in many compartments of body
- secreted by innate immune cells and epithelial cells
components of skin as first line of defense.
- defensins secreted by dermal cells
- lysozymes destroy cell wall
- sweat makes low skin pH
components of respiratory system as first line of defense.
- mucosilary blanket: mucins and defensins reduce bacterial/viral contact with cells
- alveolar macrophages
- coughing and sneezing reflex
- cilia help move pathogen along
- nitric oxide produced by lungs destroys surface of pathogens
Components of digestive epithelia as first/second line of defense.
FIRST LINE
1. cells replaced often and quickly healed if damaged (important because tissue damage is high)
2. Paneth cells make defensins
3. goblet cells make mucous
SECOND LINE:
1. patrolled by macrophages (engulf invades) and dendritic cells (alert other parts of immune system)
what are defensins?
anti-microbial peptides
what cells make mucous in first line of defense
goblet cells
how does phagocytosis kill pathogen
- membrane envaginated (pseudopod) with bacteria to make phagosome.
- phagosome fuses with lysosome (lysosomal enzymes digest bacteria) and get acidified by mitochondria and peroxisome
- digested products released to recruit more immune cells
top 3 cells that do phagocytosis
neutrophils, dendritic cells and macrophages
TLR4 is/does what?
TLR4 (toll-like receptor 4) is a PRR on the surface of innate immune cells which detects the presence of LPS (exclusive to gram neg cell wall), then initiates second messenger
what does MHC stand for
Major Histocompatability Complex
types of T lymphocytes
- CD4+ - secretes cytokines to promote/regulate immune response
- CD8+ - kills target cells
- T regulartory cells - regulates immune response and prevents harmful response to self-antigens
where do T cells mature
thymus
CD4 TCR binds to ____
MHC II
difference between MHC I and MHC II
MHC I: present in every cell in the body but only goes to surface of cell is infected, bind to CD8 cells
MHC II: present on surface of every antigen presenting cell (macrophage, DC, NKC), bind to CD4