MP324 - INTRO TO IMMUNE SYSTEM Flashcards
innate immunity
- the early phase of the host response
- present at all times
- does not increase with repeated exposure
- discrimination between groups of pathogens
adaptive immunity
- generated by specific lymphocytes
- discrimination between individual pathogens
- associated with ‘memory’
2 lineages
lymphoid lineage
myeloid lineage
anatomic barriers against pathogens
skin
oral mucosa
respiratory epithelium
intestine
innate immune cells
macrophages
granulocytes
natural killer cells
adaptive immunity cells
B cells/antibodies
T cells
inflammatory inducers of innate immunity
bacterial lipopolysaccharides
ATP
urate crystals
sensor cells of innate immunity
macrophages
neutrophils
dendritic cells
mediators of innate immunity
cytokines
cytotoxicity
3 phase response to initial infection
- innate phase
- early induced innate phase
- adaptive immune response
why does adaptive immunity occur late
the rare B cells and T cells specific for the invading pathogen may first undergo clonal expansion before they differentiate into effector cells that migrate and clear the infection
properties of Toll-like receptors
- transmembrane proteins
- extracellular region has leucine-rich repeat (LRR)
- some TLRs are located on the cell surface of dendritic cells, macrophages etc. where they detect extracellular pathogen molecules
- act as dimers
infection process
infection triggers an inflammatory response. macrophages encountering bacteria in tissues are triggered to release cytokines that increase the permeability of blood vessels and chemokines, which direct the migration of neutrophils to the site of infection.
structure of antibody molecule
variable region (antigen-binding site)
constant region (effector function)
epitope
sites within antigens to which antibodies bind
