The Immune System Flashcards
Most numerous leukocyte in the blood
neutrophils (55%)
Serve as phagocyte in (predominant) early inflammation, and then die 1-2 days later
neutrophils (polymorphonuclear neutrophils - PMNs)
Ingest (phagocyte) antigen-antibody complexes and VIRUSES
Release cytokines and leukotrienes that augment inflammatory response
Increase the type I hypersensitivity reaction
Increase and attack parasitic infections
eosinophils
Basophils contain what? what does this do? what else do basophils do? contribute to? increase at the site of?
- contain histamine
- increase at the site of allergic inflammatory reactions and parasitic infection, particularly exoparasites (ticks)
-contribute to the local inflammatory response
what are the central cells in inflammation?
mast cells - these are very similar to basophils
- contain IgE receptors
- not blood cells, rather in the tissues
- also contain histamine that increase permeability of blood vessels and smooth m. contraction
- histamine can cause vasodilation and vasoconstriction
are the MAJOR cells of the immune system (35%) include what?
lymphocytes (mature T, B, and plasma cells)
lymphocyte-like cells
NK cells
kill tumor cells and virally infected cells - recognize infected cells and tumors by changes in MHC I
also do not have to be induced by antigens
Natural killer cells
natural killer cells kill what? what else? NK cells are considered innate or adaptive?
kill tumor cells and virally infected cells
do not have to be induced by antigens
innate
provide the main line of defense against bacteria in the bloodstream?
monocytes and macrophages
precursor to macrophages and dendritic cells
monocytes
predominant phagocyte late in the inflammatory response
monocytes/macrophages
major “antigen-processing” and antigen-presenting cells that initiate the immune response?
also another that aren’t “major” that do the same thing
macrophages - major
dendritic cells
B cells are produced in the _____ and then migrate to the ______
B cells can actually mature in both the BM and the lymph nodes
Plasma cells that come from activation of B-lymphocytes produce antibodies
Located in mediastinal area, and secretes a group of hormones that enable lymphocytes to develop into mature T cells
thymus
largest lymphatic organ
spleen - macrophages here clear cell debris and process hemoglobin
consist of lymphoid tissue and produce lymphocytes
tonsils
Immune system 1st, 2nd, 3rd lines of defense?
1st line - INNATE/Native immunity
-natural barriers: skin and mucous membranes
2nd line - INFLAMMATION
3rd line - Adaptive (acquired immunity)
Group of glycoproteins that kill viruses and in general activates macrophages
*other notes say DO NOT DIRECTLY kill - rather PROTECT against viruses but prevent them from infecting additional healthy cells
INTERFERON - produced and released by virally infected host cells
Enzyme precursors when activated, undergo cascading chain rxn conversions
complement
enhances the ability of antibodies and phagocytic cells to clear microbes and damaged cells from an organism, promote inflammation, and attack the pathogen’s cell membrane can destroy pathogens directly
complement system (part of innate immunity)
*leukocyte chemotaxis; opsonization; cell lysis
causes dilation of blood vessels, pain, smooth muscle contraction, vascular permeability, & leukocyte chemotaxis
kinin system
kin to histamine
kinin system
(vascular dilation and permeability)
causes dilation of blood vessels, pain, smooth muscle contraction, vascular permeability, & leukocyte chemotaxis
enhance the acquired immune response but are part of the innate immune system
*produced primarily by?
Interleukins - stimulate the proliferation and maturation of lymphocytes
*produced primarily by macrophages and lymphocytes
interleukins
enhance the acquired immune response but are part of the innate immune system
stimulate the proliferation and maturation of lymphocytes
Do NOT DIRECTLY kill viruses but prevent them from infecting additional healthy cells
can cause death with gram negative sepsis. What other things can it do? what is it secreted by?
TNF - stimulates acute inflammation and can result in s/s of shock
- act as pyrogen to create fever
- muscle wasting (cachexia)
- proinflammatory
*secreted by macrophages in response to PAMP and TLR recognition
General term to signify a protein hormone that affects the function of cells lying near the cell of origin
Which are included?
Can be inflammatory or anti-inflammatory
Synergistic or antagonistic
Cytokines (ITT)
-Interleukins: enhance acquired immunity
- Interferons (IFN): protect against viral infections. do not directly kill, but preventing them from infecting additional healthy cells
- TNF-Alpha: death w/gram neg sepsis. can cause shock
attract leukocytes to site of inflammation (chemotaxis)
chemokines
Mast cell synthesis of mediators…which mediators?
leukotrienes, PGs, platelet-activating factor
similar effects to histamine in later stages - longer and slower response than histamine
- s. muscle contraction, increased vascular permeability
- produced by mast cells
Leukotrienes
tries to be like histamine
remember that histamine can cause both _____ and ______
vasodilation and vasoconstriction
similar effect as leukotrienes, but also induce pain…produced by mast cells
PGs
*aspirin and other NSAIDS block synthesis of this
cause endothelial cell retraction to increase vascular permeability, leukocyte adhesion to endothelial cells, and platelet activation…produced by mast cells
Platelet-activating factor
vasoactive amine that causes temporary, rapid constriction of the large blood vessels and the dilation of the post-capillary venules
also causes retraction of endothelial cells lining the capillaries
histamine
H1 receptor where are they located? what happens?
proinflammatory
- located on smooth muscle cells
- especially in the bronchi and causes bronchoconstriction when stimulated
H2 receptor where are they located? what happens?
anti-inflammatory
-abundant on parietal cells of stomach acid and induces secretion of gastric acid
first immune response to injury
inflammatory response - second line of defense
see chart neutrophils vs mono/macrophages slide 33
…
Plasma protein system that provides a biochemical barrier against invading pathogens
- complement system
- coagulation system: prevents spread of infection from site (mostly fibrin)
- kinin system
*interactions among the three plasma protein systems is finely regulated to prevent injury to host tissue and to guarantee activation when needed
______ close to the vessel contain ________ -the most important activator of inflammation
tissue
mast cells
______ in the tissues. These cells connect the innate and adaptive immune response
dendritic cells
how is the inflammatory response initiated…think molecular pathogen
the inflammatory response is initiated when tissue injury occurs or when PAMPs (pathogen associated molecular patterns are recognized by PRRs (pattern recognition receptors) on cells of the innate immune system
PRR is the same thing as toll-like receptors
regulate innate or adaptive resistance by affecting other neighboring cells
*are either proinflammatory or anti-inflammatory
chemokines or cytokines
release a number of mediators that promote and control inflammation - degranulation of serotonin release (acts like histamine)
platelets
acute inflammation causes?
heat, swelling, redness, pain (pressure exudate, PG, bradykinin)
heat and redness d/t vasodilation and increased blood flow through injured sites
leukocytosis is a manifestation of acute inflammation - what causes left shift?
more immature neutrophils present
what is considered chronic inflammation?
inflammation lasting 2 weeks or longer
neonates have transiently depressed ______ and _______ function
inflammatory and immune
adaptive immunity is…
specific
B lymphocytes are responsible for
humoral immunity that is mediated by circulating antibodies
T lymphocytes are responsible for
cell-mediated immunity
Humoral immunity produces immunoglobulins (antibodies) by…
activating B cells and creating plasma cells that produce antibodies
antibodies bind to antigens on bacteria and viruses
Cellular immunity…
T cells (control of intracellular pathogens)
- kill target directly
- stimulate other leukocytes
Both humoral and cellular immunity produce? Both interact.
memory cells
epitope
antigenic determinant - the part of the antigen that is recognized by the immune system
paratope
A paratope, also called an antigen-binding site, is a part of an antibody which recognizes and binds to an antigen
_____ are small molecules that elicit an immune response only when attached to a large carrier such as a protein; the carrier may be one that also does not elicit an immune response by itself.
haptens
antigens that induce allergic rxn
allergens
Classes of antibodies
IgG, IgA, IgM, IgE, IgD
GAMED
Dominant immunoglobulin in secretory (mucosal) immune system
IgA
*secretory piece may function to protect IgAs against enzyme degradation in the secretions
IgA which two? Does what?
o IgA – IgA1 = found
in blood, IgA2 = found in bodily secretions. Defends against pathogens on body surfaces (resp. & GI). Dominant immunoglobulin in secretory (mucosal) immune system.
*can be passed through breast milk (areola)
IgD - function?
low concentration in blood
located primarily on the surface of developing B cells
function as one type of B cell antigen receptor - and for that reason helps to regulate cell activity
IgE - least concentrated where? Mediator of? Defender against?
Least concentrated in the circulation of all Ig.
Mediator of many common allergic responses (portions bind to Mast cells)
Defender against parasites - attracts eosinophils
IgG
most abundant (80-85%)
accounts for most of the protective activity against infections
Which antibody is transported across the placenta? How many classes?
IgG1-4
Largest immunoglobulin
First produced during the primary response to an antigen
Synthesized during fetal life
IgM
Primary vs secondary response Ig
Primary response:
oInitial exposure. B-cell differentiation. IgM (after 5-7 days detected) produced then IgG against specific antigen
oPrimer of the individual’s immune system – sets stage for additional exposure
Secondary response
oMore rapid. Larger amounts of antibody produced.
oRapid b/c presence of memory cells that don’t have to differentiate.
oIgM is produced, but IgG is produced a lot more.
Adaptive immunity clonal diversity
production of T and B lymphocytes
when B and T cells are produced to recognize a specific antigen - ALL NECESSARY RECEPTOR SPECIFICITIES ARE PRODUCED leading to immature but immunocompetent B&T cells
clonal diversity - lymphocyte specificity
somehow does not require foreign antigen
results in immature but immunocompetent T and B cells
clonal diversity
production of B & T lymphocytes, antigen recognition, & lymphocyte specificity
clonal diversity
Clonal diversity: B cell development
PRODUCTION, PROLIFERATION, DIFFERENTION IN BM
then travel to lymph tissue to reside as immunocompetent cells
Clonal diversity: T cell development
The THYMUS IS THE CENTRAL LYMPHOID ORGAN OF T CELL DEVELOPMENT
development of antigen-specific T-cell receptors (TCRs)
leave thymus and travel to and reside in secondary lymphoid tissue as immunocompetent cells
Initiated when T and B cells interact with an antigen
clonal selection - an antigen selects lymphocytes w/compatible receptors
What must happen first in the clonal selection process?
must first be processed and presented on APC
dendritic cell, macrophage, B lymphocyte
Both B and T cells are ________ before they have “seen” an antigen on the surface of APC. Considered what?
immunocompetent - considered naive
when immunocompetent B cell encounters antigen for first time –> b cell with specific BCRs are stimulated to differentiate and proliferate –> then what? what does a differentiated B cell become?
a differentiated B cell becomes a plasma cell that produces antibodies –> dedicated to the secretion of a single class or subclass or antibody
T cell activation - cell mediated immunity
when antigen binds to immunocompetent t cell…
- Tc cell - cytotoxic kills pathogen directly
- Th cells activate other cells (macrophages, etc.)
- T regulatory (Treg cells) - regulate the immune response to avoid attacking self
- Memory T
MHC same as _____ and what are they?
HLA
glycoproteins on surface of all human cells except RBCs that present antigens as their primary function
2 types of MHC and what do they bidn?
- MHC I presents antigen to cytotoxic T cells (CD8)
* MHC II presents antigen to T helper cells (CD4 markers)
antibodies are present in tears, sweat, saliva, mucus, breast milk, GU, Peyer patches SI
which ones?
this is the secretory (mucosal) immune system
IgA is dominant, but IgG and IgM are present in small amounts
See slide 86 systemic immune sys vs secretory immune sys
…
body’s FINAL response slide 86
Systemic immune system - internal response (in blood and tissues)
fetus has sufficient ____ antibodies but deficient in what? can produce ____ at birth?
sufficient IgM, deficient in IgG IgA
produce IgG at birth - protective 6 mo.
Stages of disease - 4 of them - stages of communicable disease
incubation, prodromal, invasion, convalesence
incubation stage
period from initial exposure to onset of first symptoms (hrs to years)
prodromal stage
occurrence of initial symptoms are often very mild with feelings of discomfort and tiredness
invasion/infection stage
invasion is farther and affects other body tissues
convalescence
recovery occurs and symptoms decline, or the disease is fatal, or has a period of latency
Hallmark of infection?
fever
ability to produce disease
pathogenicity
capacity to cause severe disease; potency
virulence
ability to enter and replicate
infectivity
diseases with relatively high, but constant, rates of infection in a particular population
endemic
number of new infections in a particular population that greatly exceeds the number usually observed
epidemic
endotoxins
•Endotoxins – In cell walls of gram-negative bacteria. Released during lysis of bacteria. called pyrogenic bacteria bc activate inflammation & produce fever.
exotoxins
enzymes released during growth - damages cell membranes, activates second messengers, and inhibits protein synthesis
which toxins activate inflammation and produce fever, and can lead to septic shock? normally the result of?
endotoxins (endotoxic shock or septic shock)
gram - bacterial infection
virus build includes?
virion (nucleic acid surrounded by capsid)
classified by: nucleic acid (RNA or DNA), whether or not uses enzyme reverse transcriptase
intracellular parasites
viruses
Three stages of General Adaptation System?
1- alarm stage = arousal of body defenses – fight or flight
*stressor triggers the hypothalamic-pituitary-adrenal (HPA) axis which activates the SNS
2- stage of resistance (adaptation) – mobilization that contributes to fight or flight
*begins with actions of adrenal hormones (cortisol, epi, norepi)
3-exhaustion stage (allostatic overload) - progressive breakdown of compensatory mechanisms, and may lead to onset of disease
*occurs only if stress continues and adaptation is not successful
stress response - initiated by? starts with what hormone and from where?
initiated by CNS
Starts with CRH from hypothalamus –> CRH stimulates anterior pituitary to release: prolactin, GH, endorphins, and ACTH (adrenocorticotropic hormone) WHICH STIMULATES THE ADRENAL GLAND CORTEX TO RELEASE CORTISOL (glucocorticoid) stimulates gluconeogenesis, elevates glucose level, is powerful anti-inflammatory
Stress also causes stimulation of SNS
Catecholamines stimulate fight or flight (epi & norepi) from adrenal gland medulla – inc. CO & blood flow to heart, brain, & skeletal muscles by dilating vessels as well as airway vessels ALSO constricts blood vessels of viscera & skin (so it can shift blood to vital organs)
*also increases mental awareness
glucocorticoid: cortisol does what?
CORTISOL (glucocorticoid) stimulates gluconeogenesis, elevates glucose level, is powerful anti-inflammatory or immunosuppressive agent
*causes poor wound healing and an increased r/f infection
proteins found int he brain that have pain-relieving capabilities
endorphins and enkephalins
Stress-induced immune changes affect immune cell functions…causes?
causes decreased NK cells, and T-cell cytotoxicity and impaired B-cell function
