Immunology Flashcards
what are the two major systems of immunity
Iinnate immunity
adaptive immunity
- is regarded as the first line of defence
- present at birth
- responds rapidly
- has no specificity
- has no memory
is an example of which immune system
innate immunity
what are the two barriers that comprises the innate immunity
physical
chemical
- Skin
- epithelial cell layer lining mucosal surfaces
- cilia in nasal passages and bronchi
are examples of what type of barrier
physical barrier
- Acidity in stomach – low Ph destroys bacteria/pathogen
- Alkaline secretions
- Lysozyme in tears– attacks outer membrane of bacteria
are examples of what type of barrier
chemical
Competition with commensal organisms (bacteria present already in the body) is considered as what type of barrier
biological barrier
why do the few pathogens that reach the large bowels struggle to cause an effect
they must compete with billions of harmless gut bacteria
cells of the innate immunity fall under the classification of what
leukocytes
where do monocytes circulate
blood and spleen
monocytes once recruited to tissue, what can they differentiate to
macrophage and dendritic cells
where do macrophages exist
in tissues
what do macrophages secrete to recruit other immune cells
chemokines, cytokines
where do macrophages go to to present antigens, once they have become and APC
local lymph node beds
neutrophils are present in the vasculature by what percentage
40 to 60%
where do neutrophils reside
mainly in the peripheral vasculature (veins and arteries)
how do NK cells identify infected host cells
MHC class 1
what is the function of NK cells
natural killer cells destroy infected host cells in order to stop the spread of an infection.
which condition often indicates the activity of eosinophils
parasitic infection, allergic reaction or cancer
what is the complement system
The complement system is a mechanism that complements other aspects of the immune response.
what is chemotaxis
Chemotaxis is the attraction and movement of macrophages to a chemical signal.
how does cell lysis occur
Lysis is the breaking down or destruction of the membrane of a cell. The proteins of the complement system puncture the membranes of foreign cells, destroying the integrity of the pathogen.
what does chemotaxis use to bring other immune cells
cytokines and chemokines
how does agglutination work
Agglutination uses antibodies to cluster and bind pathogens together.
By bringing as many pathogens together in the same area, the cells of the immune system can mount an attack and weaken the infection.
what is the function of interferons
The function of interferons is its ability to interfere with the inhibition of virus replication.
- Slow to start – known as the lag phase
- Adaptive – responds to particular, infections and works to fight it
- Highly specific – works for a specific bacterium
- Has memory – response is faster next time
- Recognition of self and non-self
- Humoral and cellular components that work in concert.
these are examples of what immune system
adaptive immune system
which type of immunity is this: is the aspect of immunity that is mediated by macromolecules found in extracellular fluids such as secreted antibodies, complement proteins, and certain antimicrobial peptides.
humoral immunity
which immunity is responisble for the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to antigen
cellular immunity
what is an antigen
Antigen: any substance which elicits an immune response
what is an epitope/antigenic determinant
Epitope/antigenic determinant: is the portion on the antigen that is recognised by the antibody receptors
where all immune cells derived from
- All immune cells derive from Haemopoietic stem cell which is present in the bone marrow.
the common lymphoid precursor cell gives rise to which immune cells
B cells and NK cells
where must T cells mature before being released in to the blood stream
thymus
can B cells, NK cells and T cells migrate to the tissue
yes
where are mast cells only located in
tissue
where are megakaryocytes produced
in the bone marrow
B cells, NK cells and T cells are part of what lineage
lymphoid lineage
neutrophils, eosinophils, basophils, monocytes, erythrocytes and megakaryocytes to platelets, are part of lineage
myeloid linage
what is diapedesis
Adhere to endothelial cells lining blood vessels and squeeze between them to leave circulation and enter tissues.
what CD marker is found on Helper T cells
CD3, CD4
what CD marker is found on Cytotoxic T cells
CD3, CD8
what CD marker is found on B cells
CD19, CD20
what are the two function immunoglobulins provide
recognition
effector
where are the heavy chain located
where are the light chain located
which region of the antibody has the recognition function
fab arms
binding to antigen with fab arms
what is the function of the FC region
The fragment crystallizable region (Fc region) is the tail region of an antibody that interacts with cell surface receptors called Fc receptors and some proteins of the complement system.
This property allows antibodies to activate the immune system
what are the two types of light chains
lambda
kappa
which immunoglobulins structure is in the form of a pentamer
IgM
which immunoglobulin is in the form of a diamer
IgA
How do antibodies recognise millions of different antigens?
There are three hypervariable loops in each V domain, in this region there is allot of crossover, which causes specific binding site for antigen.
what is the most abundant immunoglobulin in plasma
IgG
how many subclasses of IgG are there
- 4 subclasses – IgG1, IgG2, IgG3, IgG4
which imunglobulin can cross placenta from mother to foetus
- Only IgG class to cross placenta from mother to foetus – protects baby in first months of life
which antibody is predominant in secondary response
IgG
which immunoglobulin is to large to enter tissue
IgM
which antibody is found during primary response
IgM
The central protein of complement system is?
C3
Deficient in C3 results in reccurent what
bacterial infections
what enzyme cleaves C3 to form C3b and C3a
C3 Convertase
what is C3b used for
opsonisation
how does antigen recognition occur on a b cell
On B cells, antigen recognition is mediated by surface immunoglobulins
how does antigen recognition occur on a t cell
On T cells, antigen recognition is mediated by T cell receptor (TCR)
which chromose is MHC proteins are encoded in
large cluster of genes on chromosome 6
where are Class 1 MHC expressed on
Class I: expressed on all nucleated cells including leucocytes.
where are class 2 MHC expressed on
Class II: expressed only on leucocytes which present antigen to T Cells, such as monocytes.
what must occur for a B cell to secrete antibodies
To secrete antibodies a B cell must be activated by binding antigen the differentiate into plasma cell
The antigen receptor on the B cells is the antibody that b cell is programmed to make.
what is the first antibody class a B cell produces
IgM
what is released after a CD4+ T cell binds to an antigen
the release of cytokines
cytokines stimulate B cells to do what
produce antibodies
which complement protein inititiates the classical pathway
c1q
in the lectin pathway, which complement binds on to the sugars
manose binding lectin (MBL)
other than manose binding lectin (MBL) which other complement binds on to the sugars on a pathogen
filcolin
C4bC2a is also known as what
C3 convertase
what converts c3 to c3b and c3a
c3 convertase
how does the classical pathway create c3 converatse
once c1q has binded on to the antibodies
it cleaves C4 to C4b and C4a
C2a binds on to the C4b, cleaving in to C2a and C2b
this creates C4b2a = c3 convertase
in the alternative pathway. the formation of c3 convertase occurs through factors B and D
what must happen to c3 complement first.
spontaneous hydrolysis of theoester bonds
in the alternative pathway. the formation of c3 convertase occurs through factors B and D
what happens to C3 after it becomes hydrolysed
it becomes iC3 and Factor B attaches to it
in the alternative pathway. the formation of c3 convertase occurs through factors B and D
what happens to C3 after factor B has binded on to it
it is cleaved by factor D which results in the formation of a C3b which attaches covalently to the pathogen
C3b plays a vital role in the destruction of pathogens.
C3b cleaves which complement to help macrophages engulf pathogen
c3b cleaves C5 to C5b and C5a
C5a later binds on to C5a receptors on macrophages which initiate phagocytosis
Lysis of a pathogen occurs through the formation of a MAC. which complements are envolved in the formation of the MAC
C5b, C6, C7, C8 and C9
what role does C5a play in the complement system
plays the role as chemotaxis and amplifies the imune response
C3a and C5a are known as anaphylatoxins
what do C3a bind to, to release histamine.
mast cells
which complement triggers phagocyte chemotaxis
C5a
which inhibitor controls the classical pathway
C1 inhibitor
which factors inhibit the alternative pathway
factor I
factor H
CR1
in humans MHC molecules are referred to as what
HLA (human leucocyte antigens)
which MHC has two chains
class 2
alpha and beta chain
what do B cell use as receptors to detect antigens on their surface
cell surface antibody
what do T cell use as receptors to detect antigens on their surface
T cell receptor (TCR)
what has to occur for a specific lymphocyte to undergo clonal expansion
binding of antigen
which CD marker do both T cell and cytotoxic T cells possess
C3
there are 4 classification of hypersensitivity.
which classifications are antibody mediated
types 1,2,3 - antibody mediated
type 4 - mediated by T cells and macrophages
type 1 is immediate hypersensitivity, which responds to innocuous environmental antigens.
which Ig responds to type 1 Hypersensitivity
IgE
IgE binds to Fc receptors on mast cells, which release inflammatory mediators, producing acute inflammatory reactions
avoidance
sodium chromoglycate -stabalises mast cells
anti-histamines
desensitisation
the above are all treatment methods for which hypersensitivity
type 1
what are severe type 1 reactions called
anaphylactic shock
what must be given immediatley to treat anaphylactic shock
adrenaline
type 2 hypersensitivity occurs after how many hours after exposure to antigen
12-18 hours
which type of sensitivity occurs when IgM or IgM bind to either a self-antigen or a foreign antigen on cells
type 2 sensitivity
incompatible blood transfussion reactions is an example of which hypersensitivity type
type 2
haemolytic disease of the new born, is an example of which hypersensitivity reaction
type 2
extrinsic allergic alveolitis is an example of which hypersensitivity type
type 3
type 3 sensitivity occurs after how many hours
18-24 hours
type 3 sensitivity is mediated by persistence and deposition of what?
antibody-antigen immune complexes
how long does it take for type 4 hypersensitivity to take action
48-72 hours
what is thyroglobulin
Thyroglobulin (Tg) acts as a substrate for the synthesis of the thyroid hormones thyroxine (T4) and triiodothyronine (T3),
Constant stimulation of your thyroid to release more hormones may cause the gland to become enlarged, a condition known as a goiter
this is caused by what autoimmune disease
hashimoto thyroiditis
automine disease is either organ specific or non-organ specific
which organs does autoimmune diseases affect
thyroid
stomach
adrenal
pancreas
what is the name of the non specific autoimmune disease which can affect all regions of the body
SLE - Systemic lupus erythematosus
what role does anti-TSH receptor antibody play in graves disease
the anti-TSH receptor antibody binds on to the TSH receptor which causes the thyroid gland to produce too much thyroid hormone, which is called hyperthyroidism
what type of hypersensitivity reaction would SLE be
type 3
Sjögren’s syndrome is characterised by a llymphocytic infiltrate in salivary and lacrimal glands.
what dental complications can this cause
dental caries and oral candida
dry lips
dry and lobulated tongue
caries
the above are characteristics of which autoimune disease that affects the salivary and lacrimal glands
sjogrens syndrome
