WBC

Nonspecific immune defense

Engulf foreign material via exocytosis

Monocytes once they are in tissues

Macrophages that are circulating through the blood

Can transport themselves through capillary walls and into infected/wounded tissues

Macrophages

display on their cell surface, the proteins that were on the surface of the cell or viral partical they have just digested

do not distinguish between "self"proteins

Display antigens to other more specific immune system cells to spur a more intensive immune response

WBC phagocytic like macrophages

are NOT antigen-presenting cells

destroy themselves as they fight off pathogens

Nutrophils

Macrophages

Eosinophils

basophils

mast cells

Relased by basophils and mast cells

Dilates walls of nearby cappilaries and makes them leaky

potent vasodialater

Allows macrophages and neutrophils to more easily reach the injured area

increases overall blood flow to areas of tissue injury = redness and heat

Released by basophils and mast cells

Chemicals that excite specific immune defences to activate

Specific defense of immune system

B cells and T cells

Produced by stem cells in bone marrow

type of lymphocyte

Matures in the thymus

Thymus kills T cells that recognize self antigens = decreases autoimmune reactions

T cell tolerance

Bind to MHC proteins and foriegn proteins

Lymphocytes that do not mature in the thymus

Surface has receptors that are identical to Ab proteins that B cells produce and secrete into blood stream

meadiators between macrophages and B cells

binds to self-MHC proteins on macrophage surface and displayed foreign proteins

kill virally infected cells directly

bind to self-MHC proteins and viral proteins on the cell surfaces

Secrete enzymes that perforate cell membrane and kill the cell

Control the immune response so it does not run out of control

suppress the production of Abs by B cells

1. come into contact with a foreign antigen that can bind to B cell surface receptors

2. engulf a pathogen and display its antigens on the B cell surface (like a macrophage)...T cells then recognize the foreign proteins on B cell surface and activate it

B cell clones

When a B cell gets activated, it begins to divide rapidly, producing identical clones that produce antibodies to the invading antogen

Antibodies

produced by B Cells

1. IgM (produced first)

2. IgG

3.IgD

4. IgE

5. IgA

The same B cell can produce each type at different times during an infection ("class-switch)

Responsible for Ab specifity

Antigen binding site

where Abs pind to foreign proteins

Made up of variable a.a. in one light chain and one heavy chain (1 Vl and 1Vh)

each Y shaped Ab has 2 antigen-binding sites

3 separate exons spliced together

V, D, J, Constant

300 V

20 D

4J

5'VDJC3'

Abs cross-link adjacent antigen molecules so that the invaders literally get stuck together in the blood stream

Bacteria or viruses form large, insoluble masses that can no longer invade cells and are easily engulfed by circulating macrophages

Used for soluble antigen molecules which dissolve in the bloodstream

e.g. small bacterial toxins

Ab binding allows for rapid phagocytosis and destruction by macrophages

Abs bound to the surfaces of foreign cells activate a system of 20 different complement proteins that circulate in the blood stream

Abs bound to antigens

complement proteins bridge the gap between 2 adjacent ab molecules and use a protein complex called the membrane-attack complex to lyse the cell membrane of hte invader

also activate mast cells to release histamine and bring more blood to the area

indapendant of Ab antigen binding

Cell surface molecules of bacteria yeasts, viruses, and protozoan parasites can cause membrane-attack complexes to form w/o Ab help

Ab secretion by B cells

Period after exposure but before helpful levles of Abs have been made by B cells

APCs process and display antigens to Helper T cells

Helper T cells rapidly grow and divide and activate B cells

B cells grown and divide and

7-10 days

Formed by B and T cells

Antigen specific

Live for decades

Decreases lag period in the secondary repsonse

Responsible for immunity and vaccination