2. Principles of Innate immunity Flashcards
innate vs adaptive immunity
innate = first line of defense, non-specific, present at birth, immediate response, broad range of pathogens, no memory
adaptive = second line of defense, specific, learned, time to develop, specific, memory
examples of physical barriers
respiratory epithelium, oral mucosa, tears, mucus, skin, intestine
examples of chemical barriers
enzymes: pepsin, lysozyme
complement: C3
antimicrobial proteins: defensins, RegIIIy, mucin, cathelicidin
chemical barriers of the skin
fatty acids
B-defensins
lamellar bodies
cathelcidin
chemical barriers of the gut
low pH (acid)
enzymes (pepsin)
a-defensins
RegIII
cathelicidin
chemical barriers of the lungs
surfactant
a-defensins
cathelicidin
chemical barriers of the eyes, nose and oral cavity
lysozyme
histatins
B-defensins
what are commensals
non-harmful resident bacteria
mucus and mucins in diseases of the intestinal and respiratory tracts
when there is depleted mucus bacteria can gain entry to the gut because mucins are not there to fight them off
causes inflammation of the colon
lysozyme in protection against gram-negative and gram-positive bacteria
lysozyme is more effective against gram-positive bacteria because its peptidoglycan layer is more accessible
what does lysozyme do
creates defects in the peptidoglycan layer of bacteria and exposes the underlying cell membrane to other antimicrobial agents
what do defensins do
disrupt cell membranes of microbes by inserting themselves in the lipid bilayer - leads to the formation of pores and loss of membrane integrity
which leukocytes are granulocytes
neutrophils
eosinophils
basophils
mast cells
which leukocytes are agranulocytes
monocytes - macrophages & dendritic cells
NK cells
ILCs
dendritic cells (other type)
which leukocytes came from the myeloid lineage
dendritic cell
neutrophil
basophil
eosinophil
mast cell
monocyte - macrophage
which leukocytes came from the lymphoid lineage
B cells
T cells
NK cells
ILCs
which leukocytes make up the 3 classes of phagocytes in the immune system
macrophages
granulocytes (all)
dendritic cells
most to least abundant WBCs
neutrophils
lymphocytes (B and T)
monocytes
eosinophils
basophils
where do hematopoietic stem cells reside
the bone marrow
what are granulocytes
WBCs that contain granules in their cytoplasm which contain important proteins and chemicals for an immune response
neutrophil function
phagocytosis and activation of bactericidal mechanisms
basophil function
promotion of allergic responses and augmentation of anti-parasitic immunity
eosinophil function
killing of antibody-coated parasites
mast cell function
release of granules containing histamine and active agents
what are antigen-presenting cells (APCs)
process and present antigens to T cells, express MHC, bridge innate and adaptive immunity
macrophage function
phagocytosis*
activation of bactericidal mechanisms
antigen presentation
cytokine production
dendritic cell function
antigen presentation*
cytokine production
Natural killer cell function
recognize and destroy virus-infected and tumor cells by releasing perforins and ganzymes
most important innate cell in antiviral response
innate lymphoid cell (ILC) function
secrete cytokines to activate innate immune cells
which cells bridge innate and adaptive immunity
dendritic cells
what are cytokines
proteins released from sensor cells that recruit other cells for help
what are the categories of pathogens from smallest to largest
viruses
intracellular bacteria
extracellular bacteria + protozoa
fungi
parasites
extracellular pathogen examples
fungi, worms, viruses, bacteria, protazoa
intracellular pathogens
viruses, bacteria, protazoa
what provides an initial discrimination between self and non-self
Pattern-recognition receptors (PRR)
sensor cells induce an inflammatory response by producing…
chemokines and cytokines
function of cytokines
increase the permeability of blood vessels, allowing fluids and proteins to pass into the tissues
functions of chemokines
produced by macrophages, direct the migration of neutrophils to the site of infections
how do cytokines and chemokines cause inflammation
cytokine release causes vasodilation and increased vascular permeability which causes redness, heat and swelling
chemokine release causes inflammatory cells to migrate to tissues and release mediators which cause pain
what is inflammation
a response triggered by cytokines which results in vasodilation, redness, warmth and swelling
what is a fever
by-product of inflammation caused by cytokine and inflammatory mediators
increases body temp and decreases pathogen growth
increased adaptive immune response
protective immunity mechanisms against extracellular pathogens
complement
phagocytosis
antibodies
antimicrobial peptides
protective immunity mechanisms against intracellular pathogens
NK cells
cytotoxic T cells
