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