Veterinary immunology deck I Flashcards
Name 4 types of immune system dysregulation.
hypersensitivity/allergy
immunodeficiency
autoimmune disease
immune neoplasia
define antigen
Molecules that can stimulate a specific immune-response.
What are CD markers?
The cluster of differentiation is a protocol used for the identification and investigation of cell surface molecules present on leukocytes.
What is a plasma cell?
also called plasma B cells or effector B cells
Plasma cells are differentiated B-lymphocyte white blood cells capable of secreting immunoglobulin, or antibody.
what are the two major branches of the adaptive immune system?
defense against extracellular invaders &
defense against intracellular invaders
immunity to extracellular invaders is mainly the function of what cell type?
B cells (B-lymphocytes)
B lymphocytes produce what?
antibodies
what is the humoral immune response?
B-cell-mediated immune response incorporating antibodies
immunity to intracellular invaders is mainly the function of what cell type?
T-cells (T-lymphocytes)
what is the cell-mediated immune response?
T-cells
what are the 3 types of T-cell?
cytotoxic T cells (kill cells)
helper T cells (provide signals to activate adaptive immune responses, memory T cells are helpers)
regulatory T cells (regulate immune responses)
natural killer cells are part of what type of immunity?
innate immunity
What is referred to as the humoral part of adaptive immunity?
immunoglobulins (= antibodies)
the complement system (complementary molecules that enhance or induce)
note: the complement system is also innate immunity
What is referred to as the cell mediated part of adaptive immunity?
T cells
B cells
are natural killer cells innate or adaptive
Classically, NK cells are regarded as members of the innate immune system, but recent studies have elucidated that NK cells are part of both the innate and adaptive immune response.
what are PAMPs
pathogen-associated molecular patterns
are molecules recognized by pattern-recognition receptors (PRRs), which play a key role in innate immunity in the recognition of pathogens or of cellular injury.
what are DAMPs
damage-associated molecular patterns
include proteins capable of recognizing molecules released by damaged cells
what are PRRs
pattern-recognition receptors
are proteins capable of recognizing molecules frequently found in pathogens
Name 4 types of Innate immunity cells:
neutrophils, macrophages, dendritic and mast cells
What is Lysozyme
an antimicrobial enzyme produced by animals that forms part of the innate immune system.
what is Lactoferrin
a key molecule in immune and inflammatory processes.
a mediator of both innate and adaptive responses.
can bind iron which bacteria need
cytokine definition
Cell-derived soluble protein messenger molecules that regulate the cells involved in the defense of the body
what are TLRs
toll-like receptors
can bind DAMPs and PAMPs
where are TLRs found
mainly on sentinel cell surfaces likely to encounter invaders
eg. neutrophils, macrophages, epithelial cells, enterocytes
what are LPS?
lipopolysaccharide
are large molecules consisting of a lipid and a polysaccharide, are bacterial endotoxins.
generally found on gram- bacterial cell wall
what is lipoteichoic acid?
is a major constituent of the cell wall of gram+ bacteria.
lectin definition
circulating carbohydrate-binding proteins involved in innate immune defense
what are sentinel cells?
cells such as macrophages, dendritic cells and mast cells, which embed themselves in tissues such as skin and act as the body’s first line of defense
innate immunity, PRRs found on sentinel cells
name 3 major cytokines
tumor necrosis factor-alfa
interleukin-1
interleukin 6
what is COX-2
cyclooxygenase-2
an enzyme responsible for inflammation and pain
some nsaids target this enzyme
define acute-phase protein
those proteins whose serum concentrations increase or decrease by at least 25 percent during inflammatory states.
Such proteins are termed either positive or negative acute phase reactants (APR), respectively.
what are chemokines produced by and what do they do
small proteins produced by sentinel cells
they induce leukocyte chemotaxis (response to a chemical gradient)
what are the 5 cardinal signs of acute inflammation
heat (calor)
redness (rubor)
swelling (tumor)
pain (dolor)
loss of function (functio laesa)
leukotriene definition
biologically active complex lipid, local inflammatory hormone
what is lysozyme?
are a family of enzymes with antimicrobial activity characterized by the ability to cleave peptidoglycans.
forms part of the innate immune system
what is the complement system
an essential innate defense subsystem consisting of enzymes, regulatory proteins and receptors
name 3 pathways for complement activation
- the alternative
- the lectin (mannose binding)
- the classical
what is the classical pathway for complement activation triggered by?
antibodies (so its associated with the adaptive immune system)
what are the alternative and lectin pathways for complement activation triggered by?
microbial carbohydrates so PAMPs
the most abundant complement protein found in serum?
C3
a disulfide-linked heterodimer with alfa and beta chains
which pathway for complement activation does the majority of activation?
the alternative pathway
which pathway for complement activation is the oldest?
the lectin pathway
What is FH?
factor H
a critical component of the alternative complement pathway
inactivates component C3b
antigens are associated with what type of immunity?
adaptive
dendritic cell function?
antigen-presenting cells
they link innate and adaptive immunity. The main function of these innate cells is to capture, process, and present antigens to adaptive immune cells
3 basic examples of DAMPs
host DNA
ATP
HMGB proteins (High mobility group box)
What is HMGB1?
high mobility group box 1
Intracellular, very potent DAMP -protein
triggers many cells associated with inflammation
What is flagellin?
bacterial protein, a PAMP
What is Unmethylated DNA?
DNA from single-cell organisms (mammal DNA is
methylated), is a PAMP
PRR function?
Recognition of molecules/molecule groups,
signal to nucleus,
initiation of immune response
what are RLRs and what do they recognize?
RLRs = RIG-1-like receptors
(retinoic acid-inducible gene)
recognize viral RNA
what are NLRs and what do they recognize?
NOD-like receptors
(nucleotide-binding oligomerization domain)
recognize intracellular bacteria and viruses
What are CLRs?
C-type lectin receptors
(soluble, extracellular PRRs, require Ca+)
recognize carbohydrates
What type of TLR can bind glycoproteins?
Transmembrane TLRs
What type of TLR can bind bacterial and fungal proteins?
Surface TLRs
What type of TLR can bind bacterial and viral RNA and DNA?
Intracellular TLRs
name the 3 most important TLRs?
TLR2, 4 and 9
What is an inflammasome?
Protein complex e. g. inside macrophages
Require two signals from PAMPs or DAMPs or both
Activation of caspase
Secrete big amounts of proinflammatory cytokines
Steps of diapedesis?
1 – Endothelial activation
2 –Tethering
3 – Rolling (Selectins)
4 –Adhesion (Integrins)
5 – Crawling
Transmigration/Diapedesis/extravasation
3 killing mechanisms of the innate system?
Phagocytosis (intracellular killing)
Release of antimicrobial products for extracellular killing
NK cell-mediated cytotoxicity
name 3 phagocytic cell types
Neutrophils
Macrophages
Dendritic cells (DCs)
define phagosome
Bacterium enclosed into a phagocytic cell in a vacuole
define neutrophil left shift
immature, ungranulated neutrophils released into the systemic blood in the event of acute inflammation
What is meant by ‘respiratory burst’?
is characterized by the rapid release of ROS, superoxide anion and H2O2, predominately from neutrophils, for pathogen killing. (but also macrophages)
What are NETs?
Neutrophil extracellular traps using dna filaments to create a net
what leukocyte is important in response to parasitic infection?
eosinophils
what leukocyte is important in response allergies and hypersensitivity responses?
basophils
what leukocyte releases histamine upon degranulation?
mast cells
nervous tissue macrophages are called?
microglial cells
connective tissue macrophages are called?
histiocytes
hepatic macrophages are called?
kuppfer cells
dendritic cells found in the skin are called?
langerhans’ cells
4 subtypes of DCs
Langerhans cells (skin)
Migratory
Resident (secondary immune organs)
Plasmacytoid (type-1-IFN response to viruses)
WHat are ILCs?
ILCs: innate lymphoid cells, similar to T-cells,
react immediately,
their specific functions and use so far unknown
What are NK-cells?
NK-cells: natural killer cells;
play role in innate immune response, recognize abnormal host cells, are actually lymphocytes
Note: do not confuse with NKT-cells!
After macrophages have phagocytized a pathogenic microorganism they do what?
present antigen to adaptive immune system
Innate immunity can recognize invading microorganism by what?
PAMPs (pathogen-associated molecular patterns)
describe an M1 macrophage
defend against microbes and produce proinflammatory cytokines
describe an M2 macrophage
reduce inflammation and produce cytkines that suppress immune responses
promote tissue repair
the 3 steps of clearance of soluble antigen from the blood stream
distribution
catabolism
immune elimination
What is GM-CSF?
Granulocyte-macrophage colony-stimulating factor,
a hematopoietic growth factor that functions as a cytokine
define efferocytosis
the process by which apoptotic cells are removed by phagocytic cells.
What is SAP?
serum amyloid P, the major acute phase protein in rodents
it is a PRR (like CRP is)
What is SAA?
serum amyloid A, a major acute phase protein in cats
What is AGP?
Alpha-1 acid glycoprotein
is a significant acute phase protein in mammals
What is haptoglobin (hp)?
acute-phase marker of RBC destruction.
Its value decreases and may even be absent when RBCs are destroyed at twice the normal rate.
Binds hemoglobin, inhibiting microbe iron uptake and prevents kidney damage
What is hepcidin?
an acute phase protein that regulates iron availability
prevents efflux of iron from enterocytes by binding ferroportin which makes iron unavailable to hemoglobin synthesis and thus results in infection related anemia
What is MAP?
also called pig-MAP, a major acute phase protein
major in pigs, but also found in cattle
What is a neg. APP and name a couple.
a negative acute phase protein where levels fall during acute inflammation
eg. albumin and transferrin which serve as sources of amino acids during infection
What is SIRS
systemic inflammatory response syndrome
lethal form of shock resulting from overwhelming exflux of DAMPs into the bloodstream
is a cytokine storm/ hypercytokinemia
WHat is DIC?
disseminated intravascular coagulation
a severe syndrome characterized by the dysregulation of the clotting and fibrinolytic cascades
What is MODS?
multiple-organ dysfunction syndrome
usually sequal to septic shock, poor prognosis
What is amyloidosis?
deposition of insoluble amyloid proteins in organs.
pathogenesis: amyloids are formed from erroneously formed protein chains
can eventually lead to tissue destruction and death
What are the 2 general types of intercellular signals?
volume transmission
network transmission
what is volume transmission
one of the 2 general types of intercellular signaling
involves a released mediator molecule that diffuses through extracellular fluid to the receiving cell where it binds to cell surface receptors
what is network transmission
one of the 2 general types of intercellular signaling
involves two cells coming into direct contact using complementary receptors, signals are transmitted through these 2 receptors
what is an interleukin
a type of cytokine (immune messenger/mediator molecule) that signals between lymphocytes and other leukocytes
How many interleukins are currently known and numbered?
39
what is an interferon
a type of cytokine that is produced in response to viral infections or immune stimulation
they interfere with viral RNA/protein synthesis so have antiviral activity
what are the 3 major types of interferon?
Type I interferons (IFN-alfa & IFN-beta)
Type II interferon (IFN-gamma)
Type III interferons (IFN-lambda)
What cell type produces the tumor necrosis factors?
macrophages and T cells
define pleiotropic
producing more than one effect
so in relation to cytokines - they affect many different cells
3 most important pathways that trigger cytokine release?
antigens acting on TCR (T cell receptors) or B cell antigen receptors (BCR)
PAMPs binding to PRRs on sentinal cells
antigen-antibody complexes binding to FcR(antibody receptors) on phagocytic cells
What is FcR?
means Fc receptor
is a protein found on the surface of immune cells,
name is derived from its binding specificity for a part of an antibody known as the Fc (fragment crystallizable) region.
define tyrosine kinase
an enzyme/protein integrated cell surface receptor
signal transducers
can phosphorylate
(transfer a phosphate group from ATP to the tyrosine residues of specific proteins inside a cell)
what is G-CSF
granulocyte colony stimulating factor
what is a STAT protein?
stands for signal transducers and activators of transcription
cytokine signaling is regulated in what 3 ways?
by changes in receptor expression
by the presence of specific binding proteins
by cytokines exerting opposite effects
What is the NF-kB pathway?
Nuclear factor kappa-light-chain-enhancer of activated B cells is a protein complex
the most significant signal transduction pathway in the immune system
What are NODs?
NOD-like receptor
are a specialized group of intracellular proteins that play a critical role in the regulation of the host innate immune response.
sensors of PAMPs and DAMPs
what is the NF-AT pathway?
Nuclear factor of activated T-cells (NFAT) is a family of transcription factors shown to be important in immune response.
what is the NF-AT pathway?
Nuclear factor of activated T-cells (NFAT)
signal transduction through T cell antigen receptors
NF-AT is a family of transcription factors shown to be important in immune response.
What is the JAK-STAT pathway?
a signal transduction pathway
The binding of extracellular ligand leads to pathway activation via changes to the receptors that permit the intracellular JAKs associated with them to phosphorylate one another.
What are STAT proteins?
signal transducers and activators of transcription, mediate many aspects of cellular immunity
What is the significance of C3?
complement component 3 (or C3)
It covers microbes to destroy them.
High C3 complement levels indicate inflammation in the body.
What are the most important opsonizers?
complement system and its molecules
antibodies produced by B cells
name 3 functions of complement
bacteria lysis
phagocyte chemotaxis
bacteria opsonization
Where is mannose found?
on the walls of bacteria and fungi
Name 4 triggers of the alternative pathway
• Bacteria
• Fungi
• Viruses
• Tumor cells
Name 4 triggers of the classical pathway
• Immune complexes
• Apoptotic cells
• Certain viruses
• gram-negative bacteria
What is MAC?
membrane attack complex
a complement system complex that inserts into microbial cell well to induce cell lysis
Complement activator proteins deficiency can
cause?
increased susceptibility to some bacterial
infections.
Complement regulator proteins deficiency can
cause?
autoimmune-like diseases and
uncontrollable system-wide inflammation.
Name 3 most important proinflammatory cytokines.
IL-1
TNF-alfa
IL-6
Name 3 most important proinflammatory cytokines.
IL-1
TNF-alfa
IL-6
all can behave systemically as well as locally
Name 3 most important proinflammatory cytokines.
IL-1
TNF-alfa
IL-6
all can behave systemically as well as locally
all of these are pyrogens
2 effects of histamine release in tissues
local vasodilation & increased endothelia permeability
causing redness, swelling and pain/itching
name 2 mediators that can induce retraction of endothelial cells
histamine
NO (nitric oxide)
what is VEGF?
vascular endothelial growth factor
define Granuloma
An inflammatory lesion characterized by chronic inflammation with mononuclear cell (mostly monocytes) infiltration and extensive fibrosis.
Define phagolysome.
a vacuole in the cytoplasm of a cell, containing a phagocytosed particle enclosed within a part of the cell membrane.
Define eicosanoids.
A group of signaling molecules
derived from the oxidation of fatty acids.
eg. leukotrienes and prostaglandins
– play important roles in mediating inflammation.
– derived from arachidonic acid
leukotrienes and prostaglandins are synthesized using what precursor?
arachidonic acid
define pyrogen
a substance, typically produced by a bacterium, which produces fever when introduced or released into the blood.
how does fever upregulate the innate immune response?
increases neutrophil release, infiltration and respiratory burst
how does fever upregulate the adaptive immune response?
speeds dendritic maturation, phagocytosis and cytokine action and T-cell emigration
how does fever affect T cells?
increases T-cell adhesion and transmigration to tissues.
Fever enhances immune surveillance during infection.
What is SCC?
somatic cell count and also known as california milk test, CMT
using reagent and milk to test for leukocyte content in milk indicating inflammation or infeciton
What is TGF-β?
transforming growth factor-β
a multifunctional cytokine, is anti-inflammatory and also regulates T cells
define serovar
another word for serotype
relating to variation within serotypes of a species of bacteria
e.g.salmonella enterica sp. has 2500 different serotypes based on antigenicity
what are K antigens
bacterial capsular antigens are collectively termed K antigens. this includes some pili and fimbriae of gram- bact.
not to be confused with cell wall polysaccharide antigens called O antigens
what are O antigens
bacterial polysaccharide cell wall antigens are called O antigens
not to be confused with capsular polysaccharide antigens called K antigens
what are F and K antigens?
the pili & fimbriae of some gram- bacteria are called F and K antigens
bacterial pili function?
bind bacteria together and play a role in bacterial conjugation and movement
bacterial fimbriae function?
bind bacteria to cell surfaces
what are H antigens?
flagellar antigens
bacterial flagella consisting on flagellin that aid bacterial movement
define toxoid
toxins modified by treatment with a mild denaturing agent which removes toxicity but retains antigenicity are toxoids
they may be used as vaccines eg. clostridium tetani
define virion
a complete viral particle
define epitope
the part of an antigen molecule to which an antibody attaches itself.
“antigenic determinants”
how much is a dalton (Da)
defined as 1⁄12 of the mass of an unbound neutral atom of carbon-12
(in its nuclear and electronic ground state and at rest)
define hapten
are small molecules that can only function as epitopes when bound to larger molecules
how are macrophages activated?
by certain cytokines such as:
- TNFα
- IFN-gamma
- IL-4 and -13 etc.
name 2 types of antigen processing cells
dendritic cells and macrophages
What are MHC molecules?
major histocompatibility complex molecules are specialized antigen-presenting receptors that attach to antigens
T-lymphocytes then “read” or recognize these complexes and an immune response is initiated
what are exogenous antigens vs endogenous antigens
exogenous ones are usually bacteria that grow in tissues and extracellular fluid
endogenous ones are usually viral and invade cells
what classes of MHC molecules are there?
class I
class II
what are class I MHC molecules
major histocompatibility complex molecules made by all nucleated cells and present endogenous antigens
what are class II MHC molecules
major histocompatibility complex molecules made by specialized antigen-processing cells and present exogenous antigens
what are the 3 main cell types to present exogenous antigens?
dendritic cells (most important ones)
macrophages
B cells
what are FcRs?
Fc receptors
bind to antibodies that are attached to infected cells or invading pathogens.
Their activity stimulates phagocytic or cytotoxic cells to destroy microbes, or infected cells by antibody-mediated phagocytosis or antibody-dependent cell-mediated cytotoxicity.
What are Th1 cells?
helper 1 (T) cells
stimulate cell-mediated immune responses to protect against intracellular organisms
What are Th2 cells?
helper 2 (T) cells
stimulate antibody-mediated immune responses to protect against extracellular invaders
what is PGE₂
Prostaglandin E₂
an inflammatory mediator that regulates the activation, maturation, migration, and cytokine secretion of several immune cells, particularly those involved in innate immunity
What is IgA in immunology?
Immunoglobulin A is the first line of defence in the resistance against infection, via inhibiting bacterial and viral adhesion to epithelial cells and by neutralisation of bacterial toxins and virus, both extra- and intracellularly.
important role in mediating the adaptive humoral immune defence at mucosal surfaces
What is the NF-kB pathway?
NF-κB (nuclear factor kappa light chain enhancer of activated B cells)
is a family of highly conserved transcription factors that regulate many important cellular behaviours, in particular, inflammatory responses, cellular growth and apoptosis.
What is a TCC
terminal complement complex
a complex of proteins typically formed on the surface of pathogen cell membranes as a result of the activation of the host’s complement system, and as such is an effector of the immune system.
what is cathelicidin
an antibacterial peptide that is primarily stored in the lysosomes of macrophages and polymorphonuclear leukocytes
what are the 5 types of Ig?
A
D
E
G
M
What is the bacterial heat shock protein response?
bacteria begin to produce more of these highly antigenic proteins when they are “stressed” such as during fever
what is NOS2
Nitric oxide synthase 2
is an enzyme which is encoded by the NOS2 gene and expressed in activated macrophages, generates nitric oxide (NO) from the amino acid L-arginine, and thereby contributes to the control of replication or killing of intracellular microbial pathogens.
define bacterin
vaccines containing killed bacteria
polyvalent vaccine
a vaccine containing multiple serovars for the same spp. of bacteria or other microorganism for which it is meant to inoculate
name 2 living bacterial vaccines
brucella abortus vac.
Bacillus anthracis vac.
hyphae definition
each of the branching filaments that make up the mycelium of a fungus.
define Th17 cells
T helper 17 cells are a subset of pro-inflammatory T helper cells defined by their production of interleukin 17
define adsorption
the adhesion of atoms, ions or molecules from a gas, liquid or dissolved solid to a surface.
define provirus
is a virus genome that is integrated into the DNA of a host cell.
what is ADE
Antibody-dependent Enhancement (or disease enhancement)
an adaptive immune response phenomenon in which binding of a virus to suboptimal antibodies enhances its entry into host cells, followed by its replication, thus worsening disease.
can result from natural infection or from vaccination.
What type of response do Th1 cells cause?
Th1 cells lead to an increased cell-mediated response (primarily by macrophages and cytotoxic T cells), typically against intracellular bacteria and protozoa.
are triggered by the polarizing cytokine IL-12 and
their effector cytokines are IFN-γ and IL-2.
What type of response do Th2 cells cause?
Th2 cells lead to a humoral immune response, typically against extracellular parasites such as helminths.
are triggered by the polarizing cytokines IL-4 and IL-2, and
their effector cytokines are IL-4, IL-5, IL-9, IL-10, IL-13 and IL-25.
The main effector cells are eosinophils, basophils, and mast cells as well as B cells, and IL-4/IL-5 CD4 T cells.
define protozoa
is an informal term for single-celled eukaryotes, either free-living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris.
What is a type 1 vs type 2 immune response?
Type 1 immunity is critical for defence against many intracellular pathogens, bacteria, viruses and other microorganisms. By contrast, type 2 immunity promotes immunity against extracellular parasites and helminths, helps to maintain metabolic homeostasis and regulates tissue repair following injury
what is a type I hypersensitivity reaction?
is also known as an immediate reaction and involves immunoglobulin E (IgE) mediated release of antibodies against the soluble antigen. Are allergies.
occurs within minutes of antigen exposure. It results from antigen binding to mast cell-associated IgE
This results in mast cell degranulation and release of histamine and other inflammatory mediators.
define mitogen
is a small bioactive protein or peptide that induces a cell to begin cell division, or enhances the rate of division.
Mitogenesis is the induction of mitosis, typically via a mitogen.
define Bacteriophages
also known as phages, are viruses that infect and replicate only in bacterial cells.
MHC class I region mainly codes for?
MHC molecules expressed on most nucleated cells
MHC class II region mainly codes for?
usually MHC molecules restircted to professional antigen-presenting cells
MHC class III region mainly codes for?
for a mixture of proteins many of which are important for the innate immune system such as complement
The four key antigen receptors of the immune system
TCR(T cell receptor),
MHC class I, MHC class II,
BCR (B cell receptor)
Function of MHC I
Presents all the peptides produced in the cell (like viruses bits)
For controlling what is produced in the cell
Function of MHC II
APC’s present captured antigens
What are Proteasomes
are cellular structures that digest intracellular proteins into short stretches of linear polypeptides and are essential to normal antigen processing.
Where are MHC I found
all nucleated cells (except for gametes)
Where are MHC II found
sentinel cells (DCs, macrophages etc.) and B cells
What type of response do CD4+ T cells promote
usually promote humoral immune response
- production of antibodies
- Induction of inflammation
- Macrophage activation
What type of response do CD8+ T cells promote
usually promote cell-mediated immune response
- production of cytotoxic cells
- killing of abnormal cells
Th 1 cell function
generally promote cell-mediated responses through macrophages.
Th 2 cell function
primarily involved in antibody responses through B cells.
Th 17 cell function
promote neutrophilic inflammation/ so neutrophil recruitment
Treg cell function
immunosuppression
to which type of MHC does CD4 bind?
CD4 binds to MHC class II molecules. (which is what APC’s use to present captured antigens)
to which type of MHC does CD8 bind?
CD8 binds to MHC class I molecules. (which was what infected/abnormal cells use to present the peptides produced in the cell like viruses bits or abnormal to stuff that needs destroying)
main function of MHC molecules?
to present antigens to teh immune system
on what type of cells is CD8 found on?
cytotoxic T cells
which Ig are most abundent during primary immune response?
IgM
which Ig offer protection at mucosal surfaces
IgA
which Ig are most abundent in plasma?
IgG
which Ig have an anti-helminthic effect?
IgE
antibodies’ primary function?
opsonization
what type of T cell kills virus infected cells?
CD8+ T cells
Th2 function relating to B cells?
B-cell isotype switching and thus antibody production
Th1 main function?
activation of macrophages
During adaptive immune response, which Ig appear first?
IgM
2nd most common Ig (in most mammals)?
IgM
3rd highest concentration Ig?
IgA
which one is the smallest Ig molecule?
IgG
which Ig is most abundent during secondary immune response?
IgG
define lyophilize
freeze-drying
(so the vax that need reconstitution)
define vaccine adjuvant
an adjuvant is a substance that increases or modulates the immune response to a vaccine
3 potential reasons for failure of passive transfer?
production failure
ingestion failure
absorption failure
what 3 species absolutely require colostrum (because of a lack of transplacental transfer)
horses,
ruminants,
swine
Attenuated antigen is found in what type of vaccine?
In living vaccine
describe a Type I response
dominated by CD8+ cytotoxic T cells
(endogenous antigen)
- Th1 helper cells
- interferon gamma
- macrophage activation
describe a type II response
dominated by CD4+ T cells and antibodies
(exogenous antigens)
How are hypersensitivities classified?
based on their pathogenic mechanisms
What are Type I hypersensitivity reactions?
are inflammatory responses that result from the release of contents of
mast cell,
basophil &
eosinophil cytoplasmic granules.
How is Type I hypersensitivity granule release triggered?
when antigens bind to IgE on the surface of mast cells or basophils
as a consequence of the molecules released, eosinophils are also attracted to the site
IgE production is characteristic to what type of hypersensitivity response?
Type I
What characterizes atopy immunologically?
the excessive production of IgE
3 key cells:
mast cells
eosinophils
basophils
The central event of Type I hypersensitivity reactions?
the degranulation of mast cells
What cytokine is crucial for induction of type 2 immune responses?
IL-33
Name 2 inflammatory eicosanoids
leukotrienes
prostaglandins
bonus
platelet-activating factor (PAF) is also one
What is TSLP?
Thymic stromal lymphopoietin (TSLP)
is an epithelial cell-derived cytokine expressed in skin, gut, lungs, and thymus.
What do T cells recognize?
peptides
what is ISCOM
immune stimulating complexes used as vaccine adjuvants
gives a “depot effect”
Formation of depot at the site of injection antigen trapping and slow release at the site of injection ensures constant stimulation of the immune system for production of high antibody titers.
What is a T dependent antibody response?
Antigens that require the help of T cells for B cell activation are thymus-dependent (T-dependent) antigens.
A thymus-dependent antigen is an immunogen that requires T cell cooperation with B cells to synthesize specific antibodies.
Presentation of thymus-dependent antigen to T cells must be in the context of MHC class II molecules.
TH2 cells specifically recognize class II-presented antigenic determinants and drive B-cell activation, leading to isotype class switching and antibody secretion.
What is a T independent antibody response?
Antigens that can stimulate B cells without the help of T cells are thymus- independent (T-independent) antigens.
T-independent antigens cannot induce an immunoglobulin switch or immunological memory.
T-independent responses to repeating carbohydrate epitopes stimulate antibody production but do not lead to maturation of the antibody response.
Type I hypersensitivity also called? (2)
Immediate Hypersensitivity
Mast cell and eosinophil-mediated hypersensitivity
Where are mast cells found?
in connective tissues and
mucosa including the resp. tract
antibodies’ 2 main parts?
the constant (base)
the variabale (the end of the receptor parts that can vary)
What are you testing for in intradermal allergen prick tests?
the presence of allergen specific antibodies in the animal
3 major mediators associated with pruritus
histamine
TSLP
IL-31
general mechanism behind type I hypersensitivity reaction?
IgE mediated release of antibodies.
&
mast cell degranulation and release of histamine etc.
e.g. atopic dermatitis
general mechanism behind type II hypersensitivity reaction?
Antibody-mediated hypersensitivity & Cytotoxic hypersensitivity
refers to an antibody-mediated immune reaction in which antibodies (IgG or IgM) are directed against cellular or extracellular matrix antigens
result in cellular destruction, functional loss, or damage to tissues. Damage can occur through multiple mechanisms.
e.g. HDN/neonatal isoerythrolysis
general mechanism behind type III hypersensitivity reaction?
Neutrophil-Mediated Hypersensitivity
Immune complex-mediated hypersensitivity
the formation of antigen-antibody aggregates called “immune complexes.”
They can precipitate in various tissues, and trigger the classical complement pathway.
e.g. MPGN & RAO
general mechanism behind type IV hypersensitivity reaction?
Delayed (type-)hypersensitivity
T-cell mediated hypersensitivity
involves activated T cells (which release cytokines and chemokines)
and macrophages and cytotoxic CD8+ T cells that are attracted by these
e.g. allergic contact dematitis & tuberculin test
MPGN
membranoproliferative glomerulonephritis
= when immune complexes are deposited in the glomeruli and stimulate basement membrane thickening and glomerular cell proliferation
associated with Type III hypersensitivity reactions
