Immunology Flashcards
Acute phase protein levels change in response to what?
Tissue injury
“The personal identifier molecule”
MHC
A dead vaccine is safer that a live vaccine, why?
It has less residual virulence than a live vaccine
ADCC
Antibody-dependent cell mediated cytotoxicity
As well as acting as an activator of the MAC what other function does C3b serve?
Combines with IgG to cause strong opsonisation of the pathogen
Attachment of IgE to parasites wall causes activation of the IgE Fc receptor leading to which consequences?
- Mast cell degranulation
- Worm expulsion
- Increased gut motility - smooth muscle
- increase mucus production
- Cuticle breakdown
- Eosinophil release of NO, MBP and other oxidants toxic to the parasite
- Platelet and macrophage release
Avidity
The number of bonds made by an antibody determines its strength
B cells are most useful in which type of infection?
Extracellular
By which methods can the alternative pathway be activated?
Direct activation of C3
Non-pathogenic - AgAb complexes, carbohydrates etc
Pathogenic - pathogen cell walls, selected viruses and parasites
C-reactive proteins cause what process to make bacterial cells more “tasty”?
Opsonisation
Chemotaxis
Increased cell motility in response to chemical release
C3a and C5a have no effect on the MAC complex when they are formed. What is their end action?
Activation of mast cellsChemokines
Describe a site of action of IgE.
IgE molecules bind to their specific receptors on mast cells
Dead vaccines need less doses to confer immunity to the host than live vaccines.True or False.
False
Describe the mechanical aspects of innate immunity.
Body surfaces - skin and furRespiratory tract cilia Air movement in the respiratory tractMucus secretionLiquid secretion flushes
Describe an instance in which MHC 1 May not be present on the surface of a cell. What is the consequence of this?
Some tumours and infections cause down regulation of MHC1, this means that they are unable to be targeted by cytotoxic T cells.This causes activation of NK cells which apoptose the affected cell
Draw the structure of a lymphnode. How do pig lymphnodes differ to those of other mammals?
Pig structure is “backwards”
Draw a single unit of the spleens white pulp, label the whereabouts of the two types of lymphocyte found in it.
Corona = b PALS= t
Draw a C1 complex molecule.
C1q - six binding sitesC1rC1s
Epitome
The part of the pathogen which is recognized by the immune system
Exogenous Ag processing causes activation of cytotoxic T cells and endogenous Ag process causes activation of helper T cells.True or false + correct if necessary
FalseVisa versa
How are immunoglobulins absorbed in the neonate gut?
The stomach has low enzyme concentration at this point therefore FcRn receptors on the wall of the small intestine absorb the Ig.
Extra components of the complement process can cause which immune processes?
Chemotaxis - C5b
Opsonisation
Activation of mast cells
How are useful T cells selected for in the thymus?
Their affinity for MHC molecules - useful T cells have only a low affinity for MHC 1 and 2
How do a capsule and a slime layer differ in the bacterial cell?
Capsule is well defined compared with a slime layer.
How do APCs process antigen?
Endogenous - express full processed Ag on cell surface via MHC1Exogenous - Macrophage breaks down Ag and expresses parts of it on its surface or allows other APCs to pick up and express it via MHC2
How do antibodies act in a viral infection?
Prevent viral adhesionViral agglutinationMacrophage engulfmentAntibody dependent cell cytotoxicityComplement mediated lysisPrevents viral absorption
How do bacteria evade the immune system?
Avoid adaptive immunity
- Mimic host Ag
- Biofilms
- IgA proteases
Survive phagocytosis
Avoid phagocytosis
- A proteins
- M proteins
- Capsular molecules
Manipulate cytokine secretion
How do commensal bacteria act as part of the innate immune system?
They provide a barrier to the gut mucosa for other pathogenic bacteria.
How do protozoa parasites evade the host immune system?
Hide - coat themselves with host protein
Block dendritic cells
How does colostrum become rich in immunoglobulin in the udder?
Fc receptors in the mammary tissue pull Ig from the serum into the gland as it passes through, this is secreted in the milk.
How does the secretory piece of an IgA molecule function?
It protects the IgA molecule from the harsh environment of mucosal surfaces where IgA has its action. Prevents break down by proteinases.
How is the body protected from complement mediated damage?
Complement proteins breakdown easily - LabileCells have specific complement receptorsFactors I and H cleave C3 - reduce reactionRBC’s have c3b receptors which mop up excess complement proteins
How many litres of colostrum should the neonate receive in the first six hours?
1L
How would low immunoglobulin levels in the neonate be treated in cases which are over and under 15 hours old?
Over 15 hrs = IV Ig Under 15 hrs = Oral colostrum
Humoral immunity is mediated by which type of lymphocyte?
B cells
Interleukin 10, which causes inhibition of TH1 interferon gamma release, is released by what cell?
TH2
Lymphocytes are produced in the _____ _______, a _______ lymphoid organ . Once produced T cells are moved to the ________ for maturation.
Bone marrow - primaryThymus
Label this bacterial cell.
MHC
Major histocompatibility complex
Name and state the producing cells of the different types of interferon.
IFNa/b - fibroblasts IFNgamma - T cells and NK cells
Name the four major components of the T cell receptor molecule.
Alpha subunit Beta subunitCD3 complexEither CD4 or CD8 molecule
Name two types of mucosa associated lymphatic tissue.
Peyers patches Tonsils
Name two types of animal which are know to suffer with complement deficiency disorders.
Finnish landrace lambsBrittany spaniels
NO is produced by which phagocytotic cell to cause oxidative damaged in bacterial cells?
Macrophages
Outline and briefly explain the potential outcomes of a viral infection.
Cell division - viral tumoursCell lysis - destruction of host cellPersistent infection - slow release of viral particlesLatent infection - delay between infection and symptoms
Outline the characteristics of the ideal vaccination.
Provides strong immunityLong-termConferred to foetusMinimal side effectsCheap/stableDIVA testable
Outline the formation of the membrane attack complex in the classical pathway.
C1q/r/s complex binds to Ab/Ag complex > C1 cleaves C4 and C2 into a and b molecules > C4&2b attach to nearest bacterial protein > c3 binds and is cleaved to a and b > b cleaves c5 to a and b > b causes binding of c6/7/8/9 this forms the MAC
Outline the process of complement activation via the lecithin pathway.
Mannan-building lecithin binds to pathogen surface via PAMPs C4 and C2 bind to MBL and dissociate to a and b molecules causing activation of the C3 molecule
Outline the process of phagocytosis.
Attachment of microbe to phagocyte receptorPseudopodia engulf the microbe and form the phagosomeThe phagosome fuses with the lysosome Lysosome digests microbeMicrobial proteins are expelled from the phagocyte
Outline the role of the high endothelial venules in the lymphnodes.
They grab lymphocytes using integrins from the blood and pull them into the lymphnode.
PAMP
Pathogen associated molecular patterns
PRR
Pattern recognition receptors
T cells are useful in which type of infection?
Intracellular - they destroy infected cells
The C1 complex is vital in the activation of which complement pathway?
Classical
The membrane attack complex is made up of which 5 complement proteins?
C5bC6C7C8C9
The PALS of the white pulp of the spleen surround what and contain which type of lymphocyte?
Central arteryT cells
The primary response to a pathogen is ____ than the secondary reponse.
Smaller
The variable region of antibodies can also be known as what?
The antigen binding site The functional site
These types of cytokines regulate immunity by acting on lymphocytes.
Interleukins
This interleukin inhibits the release of interferon gamma therefore causing the upregulation of B cell production.
Interleukin 10
This PRR can be found on monocytes, macrophages, mast cells and Bcells and has a non-specific manner of detecting PAMPs.
Toll-like receptors
This type of Bovine Viral Diarrhoea causes abortion and malformation of the foetus.
Cytopathic.
This type of interferon causes secretion of NO and therefore prevents viral growth in cells and also activates macrophages.From which cells does it originate?
Type 2 - IFNgammaT cells and NK cells