bio 211 ch 14: innate immune response

innate immunity

routine protection

innate immunity

considered non-specific; involves pattern recognition of specific molecules

adaptive immunity

develops throughout life; antigens cause response; system produces antibodies to bind

antigens

cause adaptive immunity response

antibodies

bind to invasive cells

host cells

adaptive immunity can destroy….

first-line defenses

barriers blocking entry

sensor systems

alert of breaching invaders

innate defenses

work to destroy invaders

skin

difficult for microbes to penetrate

dermis

tightly woven fibrous connective tissue

epidermis

many layers of epithelial cells

outermost epidermis

repels water; maintains dry environment; continually slough off along with any attached microbes

mucous membranes

digestive, respiratory, genitourinary tracts

mucous membranes

constantly bathed in secretions

mucous membranes

peristalsis of intestines, mucociliary escalator of respiratoy tract remove microbes

anti microbial substances

protect skin; mucous membranes

salt

accumulates from perspiration

lysozyme

degrades peptidoglycan

peroxidase enzymes

form superoxides

lactoferrin

binds iron

normal microbiota (flora)

competitive exclusion of pathogens; cover binding sites and consume available nutrients

normal microbiota (flora)

disruptions can predispose person to infections

propionibacterium

degrade lipids; produce fatty acids

e coli

may synthesize colicins in intestinal tract

lactobacillus

in vagina produce low pH

hematopoiesis

formation, development of blood cells

hematopoietic stem cells

where blood cells originate from

hematopoietic stem cells

found in bone marrow

colony-stimulating factors (CSFs)

induce blood cells to develop

erythrocytes

carry O2

platelets

from megakaryocytes

platelets

involved in clotting

leukocytes

important in host defenses

granulocytes

contain cytoplasmic granules

neutrophils

enguld and destroy bacteria; other material

basophils

involved in allergic reactions; inflammation

basophils

mast cells similar found in tissues; histamines

eosinophils

fight parasitic worms; also involved in allergic reactions

mononuclear phagocytes

compromise mononuclear phagocyte system (MPS)

mononuclear phagocytes

often named after location found in body

mononuclear phagocytes

includes monocytes (differ from macrophages and dendritic cells) and cell types that develop as they leave blood system

dendritic cells

engulf material in tissues, bring to cells of adaptive immune system for “inspection",” usually develop from monocytes

lymphocytes

responsible for adaptive immunity

B cells; T cells

lymphocytes highly specific in recognition of an antigen

B cells; T cells

generally reside in lymph nodes/lymphatic tissues

natural killer

cells lack specificity

surface receptors

serve as eyes and ears of cell; bind to specific ligand induces response

cytokines

voices of cell; produced by cell, diffuse to others, bind to receptors to induce a reaction

cytokines

act at low concentration; effects local, regional, systemic

chemokines

chemotaxis of immune cells; chemoattractants

colony-stimulating factors (CSFs)

multiplication and differentiation of leukocytes

interferons (IFNs)

control of viral infections, regulation of inflammatory response

interleukins (ILs)

produced by leukocytes'; important in innate an adaptive immunity

tumor necrosis factor (TNF)

inflammation; apoptosis

toll-like receptors (TLRs)

anchored in membranes of sentinel cells

NOD-like receptors (NLRs)

found in cytoplasm; detect bacterial components indicating cell has been breached; some detect damage

NOD-like receptors (NLRs)

unleash series of events to protect host; some at expense of cell

inflammasome

NLRs and cytoplasmic proteins join to form; activates inflammatory response

DsRNA detectors

detect viral RNA indicating infection; interferon release

DsRNA detectors

often has three phosphates at 5’ end; often double stranded

interferons

cause neighboring cells to express inactive antiviral proteins (iAVP)

pattern recognition receptors (PRRs)

interferons and iAVP

alternative pathway

triggered when C3b binds to foreign cell surfaces

lectin pathway

pattern recognition molecules bind to mannose of microbial cells, interact with complement system components

classical pathway

activated by antibodies bound to antigen; interact with complement system

opsonization

C3b binds to bacterial cells and foreign particles; allows phagocytes to engulf more easily

inflammatory response

C5a attracts phagocytes to area; C3a and C5a increase permeability of blood vessles; induce mast cells to release cytokines

membrane attack complexes

formed by proteins C5b, C6, C7, C8, C9 molecules assembling in cell membranes of gran negatives

macrophages

scavengers and sentries

macrophages

phagocytize dead cells, debris, destroy invaders

macrophages

live weeks or months; regenerate lysosomes

macrophages

always present in tissues; can call in reinforcements

macrophages

can become activated to increase power

neutrophils

rapid response team

neutrophils

critical role in early stages of inflammation

neutrophils

more powerful than macrophages; short life-span of 1-2 days; die once granules used

neutrophils

kill microbes via phagocytosis

inflammation

tissue damage results in…

inflammation

swelling, redness, heat, pain, sometimes loss of function

inflammatory mediators

pattern recognition receptors trigger host cells to release….

small blood vessels

inflammatory process dilates….

leukocytes

migrate from bloodstream to tissues

clotting factors

wall off site of infection

pus

dead neutrophils, tissue debris accumulate as…

damaging effects of inflammation

local tissue damage, sensitive areas, septic infections

fever

strong indicator of infectious disease

fever

slows bacterial growth

death

107 degrees (41C); fever

too high

102-105 (38-40C)';fever

fever

causes faster diffusion, faster enzyme activity

fever

important defense mechanism