Immune
Innate Immunity
Adaptive Immunity
immediate response to harmful substance
Surface barriers
skin
Internal defenses
epidermis acts as physical barrier
mucosal membranes
sebum from oil glands
lysozymes from sweat glands
hyaluronic acid in areolar tissue
epithelial lining acts as physical barrier
normal flora
mucous traps microbes
Inflammation
Release of chemotactic factors & inflammatory chemicals
Fever
NK Cells
Phagocytes
Antimicrobial Proteins
Vascular changes; vasodilation
Recruitment of leukocytes
Margination
Diapedesis
Chemotaxis
cells squeezing out of vessel to site of inf.
chemicals released to attract more immune cells
recruited cells release cytokines; initiate leukopoiesis
pyrogens released (interleukin-1) induce fever
leukocytes adhereing to CAMs on endothelial damaged tissue
Pyrogens released initiate fever
inc. body temps can damage pathogens
risks can include damage to own cells
patrol bloodstream
kill all and any unknown cell
release perforin and granzyme to destroy unwanted cell
Neutrphils & Macrophages
Eosinophils
Neuttrophils most abundant WBC
Macrophages engulf infectious agents
Basophils & Mast cells
proinflammatory chemicals secreted within granules
histamine
heparin
eicosanoids
inc. vasodilation and capillary permeability
acts as an anitcoagulant
increase inflammation
main target are parasites
release proteins to destroy cells of organism
Interferon IFN
Complement
cytokine released by infected cell
binds to receptors of neighboring cells, preventing infection
IFN stimulates macrophages and NK cells to destroy infected cells
system for microbial infections
opsonizaton
inflammation
cytolysis
elimination of immune complexes
binding to bacteria to inc. identification for phagocytosis
inc. inflammatory response by activating and attracting of mast cells. basophils, neutrophils and macrophages
form MAC protein channel; cause lysis of cell
links immune complexes to RBC to be stripped via macrophages in liver then returned to blood stream
Cell-mediated Immunity
Humoral Immunity
T-cells
B-cells
activate with antigen carried by dendritic cell
start cloning process to attack pathogen
recognize virus spike
begins cloning process
produces antibodies to seek virus and destroy
produce memory B-cell to recognize virus another time
Antigens
foreign substance that will cause immune response in body
Complete Antigens
Haptens
Self-Antigens
Mark own cells as self
Not harmful to self; very harmful to foreign
Class I
Class II
virtually all cells
certain cells
Immunogenic
Not immunogenic
Binding to body proteins may lead to allergic reaction
Reactive to antibodies released by lymphocytes
Antibodies
characterized as an immunoglobulin protein produced against a specific antigen
facilitates destruction of pathogens by other immune cells
Y-shaped soluble protein made of 4 polypeptide chains; 2 heavy & 2 light
Actions
Major classes
IgA
IgD
IgM
IgE
IgG
Exposed FC portion after binding promotes:
Binding of antigen binding site causes:
Agglutination
Precipitation
Neutralization
Opsonization
Activation of NK Cells
Complement Fixation
Antibody-dependent cell-mediated cytotoxicity (ADCC)
binding of Ab to Phagocytic cells; triggers phagocytosis
activates complement
antigen-antibody complex becomes insoluble; precipitates particles and are engulfed
cross-link cells causing a clump
antibody coats pathogen preventing binding of cells
most abundant major class
facilitates all actions
found in body fluids
pentamer (5 monomers)
found mostly in blood
most efficient at agglutination and binding complement
found in exposed areas of environment
produced in secretions
especially effective at agglutination
works along with monomer from of IgM
antigen-specific B-lymphocyte receptor
can identify when immature B-lymphocytes are ready for activation
produced in response to allergic reactions & parasite infections
causes release of histamines & attracts eosinophils
Immune cells
Origin of immune cells
Red Bone Marrow
Thymus
Produces all leukocytes before entering bloodstream except T-cells
Housing of immune cells
Lymphatic tissue
Select organs
Epithelial tissue
Connective tissue
T-cells migrate to thymus to mature and differentiate
Positive selection process
survival of cell dependent on capability of binding to MHC molecule
T-lymphocytes
B-lymphocytes
Macrophages
NK cells
alveolar macrophages
dendritic cells
mast cells
Negative selection process
survival of positive T-cell dependent upon not recognizing self-antigen
End result of both processes is Helper T-cell or Cytotoxic T-cell
Antigenic Determinants
specific site on antigen that is recognized by components of the immune system