process of awareness and recognition

discrimination of self and self environment

protection and regulation mechanisms

advantages and drawbacks-immune

adaptive or aquired immune system

innate immune system

memory or adapts to particular diseases encountered during life of organisms

major cells: T and B cells

nonspecific first line of defense

more primitive in evolution

major cells: phagocytic cells, antigen-presenting cells

humoral immunity

cell mediated immunity

serum from animals previously immunized to diptheria could transfer their immunity to non immunized animals

antitoxin component was found to be in the gamma globulin of serum "immunoglobulin" or "antibody"

since antibodies were in blood (body fluids were called humors) termed humoral immunity

1. specific binding to antigens

2. participation in a number of effector reactions like: complement fixation, allergic reactions, cell activation

These 2 functions are carried out by diff parts of the Ab molecule

IgG

IgM

IgA

IgE

IgD

direct lysis of susceptible cells by insertion of approprirate membrane attack complex

opsonizaiton of anitgen for subsequent engulfment and intracellular killing by phagocytes

c3e mediated release of mature PMN from bone marrow

series of components activated w/ products that do a particular

mediators of natural immunity

refulators of lymphocyte activation growth and differentiation

activators of inflammatory cells

stimulators of immature leukocyte growth and differentiation

found white blood cells in starfish could ingest microorganisms, termed phagocytes

subsequently found these in mammals too

these are more active in immunized animals

collaboration between adaptive and innate IS

these arms of the immunse system have many ways of interacting

cells of the innate immune system WARN the cells of the adaptive immune system that a foreign antigen is present "antigen presentation"-like soldier showing captain foreign material-up to captain ultimately what hes gonna do with it

adaptie cells produce signals that enhance the effectiveness of the innate responses

b cells-origin of antibodies, humoral immunity, anitbodies act directly to neutralize invaders, also trigger potent cell mediated immunity, produced in bone marrow, act against extracellular invaders of toxins

t cells-produced in bone marrow, mature in thymus, origin of cell-mediated immunity, coordinate IS, act against infected cells

helper t cells-provide help in the form of secreted cytokines or cell cell interactions to B, Tc, and macrophages

T cytotoxic cells, kill infected cells by lysis

T regulatory cells, maintain self tolerance

natural killer cells-cytotoxic to tumors, virally infected cells

monocyte/macrophages-phagocytic antigen presentation

dendritic cells-antigen presentation-major link b/w immune system, constant antigen presenetion

mast cells-antiparasistic, allergy

neutrophils-phagocytic, inflammatory

eosinophils-phagocystic, anti parasite

basophils-work w/ eosinophils, allergy

anatomic barriers-skin mechanical acidic barrier, mucous membranes trap pathogens, cilla propel foreign material outwards, normal flora compete for niches

primary lymphoid organs-origin of immune cells

secondary lymphoid organs-brings together pathogens and immune system

primary organ

bone marrow

bone marrow

all blood cells originate here

fetal live=bone marrow functionally

all hematopoietic cells except T cells mature here

primary organ

site of t cell maturation

immature t cells migrate from bone marrow 95% thymocytes dies (prevents self reactivity)

mature t cells emerge and enter blood and lymphatics

as we age, size and func declines

bi lobed orfan, located close to the heart

each lobe divided into lobules

each lobe has outer and inner cortex

secondary organ

designed to trap antigens, initiate immune resoponses

lymph fluid compartment of blood plasma, seeps across capillary walls, returns to either the blood or to a network of lymph capillaries, termed lymphatic vessels

highly organized

located at points of convergence of lymphatic vessels

collect fluids from tissues, promotes antigen presentation to T helper cells

cortex w/ B cells organized in follicles proliferating

paracortex-T cells and dendritic cells (antigen presentation)

medulla-macrophages and plasma (B cells)

secondary lymphatic organ

located behind stomach

collects antigen from blood

similar role to lymph noedes

also site of disposal of RBCs

red pulp- red blood cells are disposed

white pulp-lymphocytes

mucosal assoc lymphoid tissue

diffuse aggregation of lymphoid tissue that protect mucosal surfaces, respiratory epithelia

gut assoc lymphoid tissue

tonsils

adenoids

appendix

peyers patches (sm intestine)

directed movement of leukocytes along a cocen gradient of chemoattractants

chemoattractants may be derived from the tissue or from infecting organisms

stimulate leukocytes by binding to receptors on the neutrophils surfaces

interalization of particulate matter by cells

phagocytes-usually neutrophils and macrophages

particles-usually bacteria

hematopoeisis

process of maturation of blood cells

lyphopoeisis-maturation of T and B lymphocytes

erythropoiesis-maturation of red blood cells

first step in infection is activation of innate immune system response, causes inflammation

-major clearance of invading organisms, cell mediated

second step is to alter the adaptive immune response-antigen presentation, both cell and humoral components

cognitive-antigen recognition and binding

activation-follows antigen exposure, charac by lymphoproliferation

effector-antibody production and cell mediated effector functions

usually achieved by molecules on the surface of immune cells

also acheived by immune molecules in circ-ex anitbodies

dependent on having a large repertorie of all these molecules capable of recog different specificities

over 10 billion est ab specificities

each b cell produces only one set of ab molecules to only one specificity

different b cells produce dif specificites

info needed for these specialities is contained in germline DNA

the IS randomly generates a great diversity of antigen specific receptors, some of which are self reactive

cells bearing these self receptors must be eliminated

prevention of self reactivity is not genetically programed

self reactivity is prevented by processes which occur during development

antigentic determinants (epitopes)

restricted portions of a molecule which are involved in the actual binding with the combining site of a particular immunoglobulin

the number of distinct antigenic determinants on an antigen molecule varies w/ its size and chemical complexity

an ab raised against a particular antigen may "cross react" w/ another antigen if the second antigen contains antigentic determinants found in the first

these determinants must be the ones recog by the ab on the first antigen

don't want to overrecog something

how cells work together: the big picture

microbes invade

first sensed by cells of innate IS

phagocytose microbe and present its antigents to T helper cells and antigen presenting cells

helper t cells secrete cytokines which trigger APC to present and phagocytose more effectively, cause helper T cells to multiply, enable b cells to produce antibodies, trigger T cytotozic cells to kill infected cells

B cells secrete Abs

Tc cell kills other infected cells