principles of innate immunity

what are the two defenses of the immune system

innate and adaptive

innate immunity is what line of defense for

first line for non specific

adaptive immunity is what line of defense for

second for specific immunity

what are the two types of adaptive immunity

humoral and cell mediated

what is humoral immunity mediated by

B cell

what is cell mediated immunity mediated by

T cell

examples of anatomical physical barriers

skin, oral mucosa, respiratory epithelium, intestine

examples of chemical barrier complement/antimicrobial proteins

C3, defensins, regllly

examples of sensor innate immune cells

macrophages, granulocytes, natural killer cells, epithelial cells

examples of adaptive immunity sensor cells

B cells/antibodies, T cells

epithelial surface of skin

stratified epithelium

mechanics of skin stratified epithelium

longitudinal flow of air or fluid

chemical composure of skin stratified epithelium

fatty acids

antimicrobial peptides of skin stratified epithelium

B-defensins, lamellar bodies, cathelicidin

gut epithelial surfaces

single cell layer of columnar epithelium

mechanics of gut epithelial surfaces

longitudinal flow of air or fluid

chemical composure of gut epithelial surfaces

low pH and enzymes (pepsin)

antimicrobial peptides of gut epithelial surfaces

a-defensins (cryptdins), reglll (lecticidins), cathelicidin

lung epithelial surfaces of the upper airway

pseudostratified columnar epithelium

lungs epithelial surfaces of lower airway

single cell layer of columnar epithelium

mechanics of lungs epithelial surfaces

movement of mucus by cilia

chemical composure of lungs epithelial surfaces

pulmonary surfactant

antimicrobial peptides of lungs epithelial surfaces

a-defensins, cathelicidin

eyes/nose/oral cavity epithelial surfaces

pseudostratified columnar epithelium

mechanics of eyes/nose/oral cavity epithelial surfaces

tears, nasal cilia

chemical composure of eyes/nose/oral cavity epithelial surfaces

enzymes in tears and saliva (lysozyme)

antimicrobial peptides of eyes/nose/oral cavity epithelial surfaces

histatins, b-defensins

what does lysozyme do to the peptidoglycan layer

creates a defect and exposes underlying cell membrane to other antimicrobial agents

why is lysozyme effective against gram-positive bacteria

greater accessibility to peptidoglycan

what do lysozymes do to the gram-positive and gram-negative cell walls

digests

what are defensins

amphipathic peptides that disrupt the cell membranes of microbes

what happens when positively charged defensins interact with charged surface of cell membrane

become inserted in the lipid bilayer and forms pores and causes loss of membrane integrity

what brings the defensin into the lipid bilayer

electrostatic attraction and transmembrane electric field

2 broad cells of the innate immune system

granulocytes and agranulocytes

types of granulocytes

neutrophils, eosinophils, basophils, mast cells

types of agranulocytes

monocytes, innate lymphocytes, dendritic cells

types of monocytes

dendritic cells and macrophages

types of innate lymphocytes

NK cells and ILCs

what cells make up the 3 classes of phagocytes in the immune system

macrophages, granulocytes, and dendritic cells

WBC normal range of neutrophils

2000-7000, 40-70%

WBC normal range of lymphocytes

1500-4000, 20-40%

WBC normal range of monocytes

200-800, 2-8%

WBC normal range of eosinophils

40, 1-6%

WBC normal range of basophils

less than 10, less than 1%

what is the myeloid lineage mostly comprised of

most cells of innate immune system

lineage of granulocytes

myeloid

granulocytes contain what in their cytoplasm

granules, membrane organelle containing proteins and chemicals needed for immune response

amount of neutrophils and function

>50% of leukocytes, first line of defense

amount of eosinophils and function

1-3%, important in parasitic infection

amount of basophils and function

<1%, combat parasitic infection

mast cells function and location

alert system, reside in tissue

who discovered granulocytes and how

paul ehrlich, using acid base staining

neutrophils mechanism of action

phagocytosis and activation of bactericidal mechanisms

eosinophil mechanism of action

killing of antibody coated parasites

basophil mechanism of action

allergic responses and augmentation of anti parasitic immunity

mast cells mechanism of action

release granules containing histamine and active agents

lineage of myeloid APCs (antigen presenting cells)

myeloid

what do antigen presenting cells do

process and present antigens to T cells

what do APCs express

MHC-II (major histocompatibility complex)

types of APCs

monocytes, macrophages, dendritic cells

monocytes abundance and function

5-10% of WBCs, precursor to macrophages

macrophages function

phagocytic, engulf pathogens

dendritic cells function

present antigens to T cells to initiate adaptive immune responses

what is the most important type of APCs

dendritic cells

macrophage mechanism of action

phagocytosis and activation of bactericidal mechanisms, antigen presentation and cytokine production

dendritic cells mechanism of action

antigen uptake in peripheral sites, antigen presentation and cytokine production

innate lymphocytes lineage

lymphoid lineage

types of innate lymphocytes

natural killer cells and innate lymphoid cells

what do NK cells do

recognize and destroy virus infected and tumor cells

what do ILCs do

secrete cytokines and activate innate immune cells

what forms the bridge between adaptive and innate immune responses

dendritic cells

what are the cells of the adaptive immune system

lymphocytes to T and B cells

types of T cells

helper and cytotoxic

helper T cell function

helps cytotoxic T and B cells in their immune functions

cytotoxic T cell function

kills virus infected and damaged cells

types of B cells

plasma cell

plasma cell function

produce antibodies

inflammatory inducers of innate immune system

bacterial lipopolysaccharides, ATP, urate crystals

sensor cells of innate immune system

macrophages, neutrophils, dendritic cells

mediators of innate immune system

cytokines and cytotoxicity

target tissues of innate immune system

production of antimicrobial proteins, induction of intracellular antiviral proteins, killing of infected cells

are all microbes pathogens? if no, what else could they be

no, microbiome/commensals

what is the difference between pathogens and commensals

if it induces damage

what is a PRR

pattern-recognition receptors

what do PRRs do

recognize simple molecules and patterns of molecular structures (PAMPs)

what is PAMPs

pathogen-associated molecular structures

what do sensor cells express

PRRs

example of PAMPs

peptidoglycan (PGN), lipopolysaccharide (LPS),CpG DNA

examples of PRRs

toll like receptors (TLRs), NLRs

how do sensor cells induce an inflammatory response

producing mediators such as cytokines and chemokines

what triggers macrophages to release cytokines and chemokines

bacteria

what do cytokines do to blood vessels

increase permeability, allowing fluid and proteins to flow into tissues (redness, heat, swelling)

what do chemokines do

direct migration of neutrophils to site of infection

what does the migration of neutrophils (inflammatory cells) into tissues cause

inflammatory mediators that cause pain are released

how does the response triggered by cytokines (redness, heat, swelling) help the innate immune response

promotes immune cell migration to site of infection, and immune cell function at an infection site

what is the cause of a fever

cytokines and inflammatory mediators

what does a fever do in tissues

alter metabolism so heat output increases, increasing body temp

what decreases and what increases during a fever

pathogen growth decreases, adaptive immune response increases

what are the 3 strategies the host adopts to deal with threat posed by pathogens

1. avoidance: physical and chemical barriers

2. resistance: sensor cells and effector mechanisms

3. tolerance: inflammation