Unit 1 Flashcards
What is an antigen, where can it be found
A substance recognized by the body as being foreign which can cause an immune response
What is an immunogen
Any substance that is capable of stimulating an immune response
Define an immune response
The reaction of the body to substances that are foreign or interpreted as being foreign
What is a Hapten
a small molecule which, when combined with a larger carrier such as a protein, can elicit an immune response, cannot activate immune system by itself
What is immunogenicity
The ability of an Ag to stimulate an ab response
What RBC antigens are more or less immunogenic, put the in order from most to least
ABO>D>K
ABO creates worse reaction if non match
What factors influence immunogenicity
foreignness, size, chemical composition/ complexity, solubility/ physical characteristics/ charge, degradability, accessibility
What is alloimmunization
when there is an immune response to foreign antigens because of exposure to cells or tissue from a genetically different member of the same species
ie blood transfusion
How can antibodies be categorized
naturally occurring: no stimulation needed, produced due to response to substances in the environment (pollen, bacteria membranes)
immune based: non naturally occurring, could occur due to blood transfusion or baby to mother transfer
What charge do RBCs have overall, how does this affect the way that they interact with each other
RBCs have a net - charge, they naturally repel from each other
explain what Zeta potential is
A potential is created because of of an ionic cloud of cations that are in the blood that attract the zone of negative charge on a RBA, it keeps RBCs 25nm apart at all times. Na is usually the cation present in blood
What is an autoantibody
Antibody directed against an individual’s own antigenic determinants
i.e. Warm Auto Hemolytic Anemia, causes autoimmune disease
What is a heteroantibody? What other name does this term have?
Xenoantibody- ab produced in a species against an Ag present in another species
Describe in vivo vs in vitro
in vivo: within the body
in vitro: artificial environment outside of body
What are the primary and secondary organs of the immune system
primary-BM, thymus, liver (in fetus only)
secondary-Lymph nodes and spleen,
What organs: produce B cells produce T cells stores iron and has erythropoiesis during fetal stages of life processes and aids in Antigen detection
BM-B cells
Thymus-T cells
Liver-
Lymph nodes and spleen
Where do all immune cells originate from
pluripotent hematopoietic progenitors, turn into Myeloid or lymphoid precursor cells
What are the myeloid lineage cells, what is their general role and what type of immunity do they aid in
phagocytes: monocytes, neutro, eos, baso RBCs Platelets Can destroy engulfed pathogen or process it and present them to lymphs (APC) innate and acquired immunity
What are the lymphoid lineage cells
T, B and NK cells
What are cytokines and what is their role
polypeptide substances that are immune response regulators, can activate and deactivate cells, regulate immune specificity, intensity and duration
What is the role of B cells
- can recognize one or a set of antigens on foreign cell, no help needed
- APC to CD4 T helper
- Can be activated into plasma cells and secrete abs
- Can become memory cells that remain in the system
What do antibodies do after they have been produced by a plasma cell?
They can circulate freely in the plasma, body secretions and lymphatic sys.
Can bind to antigen on foreign cell to block it from attaching to something else
Are lysed when Complementary system is activated by Ag-Ab complex
What do T cells do? Name the function of each type of T cell
CD4-T helper, can recognize ag after APC presents one, help B cells evolve into plasma cells which causes them to produce antibodies
CD8-Cytotoxic T- Destroy target cells often associated with cancer or viruses
CD8+ T suppressor- shuts down immune response once pathogen is destroyed by releasing lymphokines
What “tools” do T cells use to create an immune response/ recognize an antigen
CD4- need HLA class II- best for finding bacteria CD8- need HLA class I- best for finding viruses
What types of specific markers do each type of T cells have?
CD3 clusters of differentiation when non differentiated
CD4 T helper
CD8 Cytotoxic T cell
CD8+ Suppressor cell
What cells are APCs?
macrophages, B lymphocytes, dendritic cells (langerhans), Glial cells, Kupffer cells, osteoclast, thymus
What cells are part of innate immunity? and adaptive?
innate- neutrophils, macrophages and other APCs
adaptive- B, T and NK cells
What special methods can NK cells use to kill pathogens
They can lyse antibody coated cells, do not need MHC molecules to recognize pathogens, lyse virally infected cells and tumor cells directly with its HLA class I
Are haptens immunogenic?
no, they cannot illicit an immune response on their own.
How do cells bind to antigens?
B or T cells bind to the epitope of the antigen on a foreign cell
What is the difference between an immunogen and an antigen?
immunogens always elicit immune responses, antigens do not necessarily
What are opsonins and what do they do
molecules that are free roaming that aid Macros and neutrophils in phagocytosis, “prepare for eating”, they do this through opsonization, they can bind to phagocytes or bind to pathogens to coat them and create binding sites for immune cells to grab onto, forks
What are the 2 main types of opsonins?
- complement protein C3b (from complement system)
- antibodies
What antigens are produced during a primary immune response (initial exposure to an antigen)
IgM in large quantities first, then igG in small quantities
What processes are involved in the primary immune response?
phagocytosis and alternative pathway that triggers the complementary system
During the log phase of the primary immune response, what changes do the antibodies go through?
IgM converts to IgG through heavy chain switching in low amounts, IgM breaks apart to become single IgG antibodies
What proportion of IgM vs IgG during the primary response
50/50
How does the immune system react differently to a second exposure (secondary immune response)
T and B cells are faster to react to threat due to memory cell activation
log phase is much shorter, IgG produced almost immediately, this effect is called Anamnestic
How does the secondary immune response relate to a blood transfusion?
A patient who was given slightly wrong transfusion might have a smaller reaction the first time, not notable, would take a while for body to create adaptive immunity/ memory cells
Once introduced to the same blood a second time if the positive reaction is not detected, the second time will be much more severe and likely fatal
What is the proportion of IgG to IgM in a secondary immune response
much more IgG to IgM,
Primary immune response is characterized by a lot of what type of antibody?
IgM
What antigens are most abundant? put them in order from least to greatest
GAMDE
What size are antigens usually and what are they made of?
over 10,000 daltons
proteins, glycolipids, glycoproteins and lipoproteins
anything smaller is usually a hapten
What RBC antigens make the best immunogens
proteins: Rh, M and N
What factors influence antigen immunogenicity
size, foreignness, composition, dosage, route of exposure
Are larger or smaller antigens more immunogenic?
larger
What structure on an antigen gives it specificity
the epitope on the cell surface, antigenic determinant
What RBC antigen is most immunogenic
the D antigen
Where are antigens in the body
ABO antigens in RBCs, and all blood cells kidneys and heart
What antigens do WBCs have and other nucleated blood cells
HLA human leukocyte antigen
What types of antigens are a concern in BB?
RBC WBC and platelet antigens, for successful blood transfusion
What is the least common immunoglobulin
IgE, it is only around during allergies and anaphylaxis
What part of the immunoglobulin determines the antibody class
the heavy chains if alpha beta gamma delta or epsilon
What is the only immunoglobulin that can cross the placental barrier
IgG
What are the different types of IgG immunoglobulins
IgG1 -IgG4
What part of an antibody binds to an antigen
The variable region, Fab
Describe the “Chains” in immunoglobulin
2 light chains, 2 heavy chains, connected by a disulfide linkage, heavy chains on inside, light chains on outside
What is the function of IgA
secretory protein found in saliva, breast milk, mucous
What is the function of IgD
interacts with mast cells, causes allergies
What is the function of IgE
also allergy and type 1 hypersensitivity, works with mast cell, also present in parasitic infection, coats helminths and helps other cells attach to it to kill it. Can bring in neutrophils or eosinophils
What is the function of IgG
first type you have as a child, can cross placenta, work with B cells to help with specific antigens, tends to help with opsonization
What is the function of IgM
most common on surface of B cells, pentamer that can bind to more things at one, aids in complement much faster than other immunoglobulins
What are the different functions of all immunoglobulins
neutralization-binds to binding sites on pathogens
opsonization-binds to pathogen to aid in phagocytosis
signaling- as a receptor on B cell surface
complement-bind to pathogen, complement proteins bind to Fc region and starts up complement cascade ending in cell lysis of pathogen
Cytotoxic cell aiding- bind to NK cell and pathogen, help complete cell lysis
Which immunoglobulin has the highest valence?
IgM
What is the structure of each immunoglobulin
IgG-monomer IgA-dimer IgM-Pentamer IgD-monomer IgE-monomer
What is affinity? Avidity?
Affinity- the strength an ab can bind
avidity- the total strength of binding molecules
Which antibody has the highest affinity? Which has the highest avidity
highest affinity IgG
highest avidity IgM
Which IgG antibodies are good for activating complement? Put them in order from best to worst
IgG3
IgG1
IgG2
IgG4
KIDD is an example of what immunoglobulin
IgG
Which antibody is most clinically significant
IgG- can decrease RBC survival time the most, most important in BB to avoid transfusion reactions, because it has the highest affinity
Which IgG antibodies are mostly Rh system antigens
IgG1 and IgG3
Which part of the blood has viable amounts of compliment, which could cause hemolysis if antigen antibody positive reactions occur
the serum, which is why in BB we use the serum to see a reaction visually
What factors affect the speed of agglutination
the amount of antibodies and the amount of antigen sites,
post zone-if too many antigens, agglutination slows down
prozone-If too many antibodies the same occurs
What might cause a false negative in BB to occur
if the proportions of antibody or antigen are wrong, the blood will not visibly agglutinate and the BB might think they are a good match, a false negative
What are the two stages of agglutination
1- sensitization, antibody attaches to antigen on RBC
2- lattice formation-RBCs aggregate due to attached antibodies, visible rxn
What factors affect sensitization
temp, pH, time, ionic strength (zeta potential), ratio of an to ab
What antibody reacts most to incompatible RBCs at body temp
37C- IgG
What antibody reacts most to incompatible RBCs at cold temperatures
22C or colder- IgM
What antibody reacts the most to a low pH
IgM
What does LISS do?
lowers ionic strength in RBCs causes them to be too close to each other, makes them agglutinate easier with IgG
What does Bovine albumin do
increases electric current to lower zeta potential, affects distance between RBCs
What does PeG do? Polyethylene glycol
removes H20 (dehydration) to enhance antibody-antigen reactions
What do proteolytic enzymes do
used to decrease RBC negative charge, lowers zeta potential, denatures antigens
What factors affect the lattice formation of RBCs?
the size of the ab, amount of abs, amount of antigens, location of antigens and zeta potential
How are agglutination reactions graded
from 0 to 4+
0- negative no clumps
4- solid clump, clear supernatant
What does a positive reaction in gel look like for agglutination testing
a band at the top, means the antigen and antibody have formed a complex too big to move through gel, the further up the band, the more severe the reaction, if sitting at the bottom, no reaction occurred, negative result
What organ produces the complement proteins in the complement system
the liver
What are the function of the complement system
opsonization aid in phagocytosis
lysis of abnormal cells, including viruses
inflammatory response- C3a works to call other cells to action
cripple pathogens by covering them
What are the 3 ways to activate the complement system
classical, alternative and lectin pathway
classical is the main focus in BB
antigen-antibody binding
How many IgM molecules are needed to activate complement? how many IgG?
1 IgM
2 IgG
What are the proteins in the complement system and what order do they activate in where are the complexes
C1-C9
C1-C4-C2-C3-C5-C6-C7-C8-C9
C3b-opsonization
C5-C9 mac complex
C3 convertase: C4b, C2 and C3
What do the a and b on complement proteins mean
a-fragment that triggers inflammation
b-active fragment of complement
What are homozygous and heterozygous
homo- same allele on a pair of chromosomes
heter- 2 different alleles on pair of chromosomes
What is dosage
antibodies reacting more strongly with homozygous RBCs than heterozygous RBCs, more binding sites for abs to attach to
Which RBC would have the strongest dosage to a Jka antigen
Jk(a+b-)
Jk(a+b+)
Jk(AA)- stronger reaction, double dose of A antigen
Jk(AB)
What blood types are most affected by dosage
Rh, Duffy, Kidd and M
Kidds and Duffy the monkey (Rh) eat lots of M&Ns
What is an amorph
A silent gene, no detectable antigen
What is polymorphic
2+ alleles at a given locus
Would a population be better off being more polymorphic or amorphic? What blood type system are most _?
polymorphic RH and MNS
What factors in terms of location affect the reaction to antigen D ?
Trans location dramatically reduces the expression of D, if Ce is trans to D
Number the gene interaction effect of the following 0 to 4
dCe/DcE
dcE/Dce
DCE/Dce
dCe/DcE 0+ weak D
dcE/Dce 2+ or 3+
DCE/Dce 4+
What needs to occur for Sex linked dominant inheritance to show for a trait?
Sex linked recessive?
one copy needed can be X or Y linked
2 copies of X-affects only women
What blood groups are dominant? Recessive?
A and B are dominant
O recessive
What does the + and - mean on a blood group antigen symbol
+ antigen present
- antigen not present
How is the Kidd system notated
Jk
How is the lewis system notated
Le
How is the Duffy system notated?
Fy
Which portion of the immunoglobulin molecules binds to complement?
heavy chain constant region
Which of the following is not involved in the acquired (adaptive) immune response?
a. Phagocytosis
b. Production of antibody or complement
c. Induction of immunologic memory
d. Accelerated immune response upon subsequent exposure to antigen
phagocytosis
- Which cells are directly involved in the production of antibodies?
B lymphocytes
Which cell is involved in antigen presentation and recognition following phagocytosis?
Macrophage
- The role of the macrophage during an antibody response is to
d. Process antigen and present it.
Which immunoglobulin is the primary Ig produced in the primary immune response?
IgM
Which of the immunoglobulin is primary Ig produced in the secondary immune response?
IgG
Which of the following immunoglobulins is most efficient at binding complement? (Do not consider subtypes)
IgM
How is the classical complement cascade activated?
c. Antibody and antigen formation
Which of the following is known as the “membrane attack complex” in the classical complement pathway?
d. C5b, C6, C7, C8, C9
- Which of the following refers to the effect of an excess amount of antigen present in a test system?
Postzone
13Which of the following refers to the presence of an excess amount of antibody present in a test system?
Prozone
Molecules, like C3b complement, that promote the update of bacteria for phagocytosis are:
a. Opsonins.
Select the term that describes the unique confirmation/shape of the antigen itself that allows for antibody recognition and binding by a specific antibody is?
Epitope
Which of the following terms refers to the net negative charge surrounding red blood cells?
d. Zeta potential
When a recessive trait is expressed
b. Two genes carrying the trait were present.
When a male possesses a phenotypic trait that he passes to all his daughters and none of his sons, the trait is said to be:
a. X-linked dominant.
When a female possesses a phenotypic trait that she passes to all of her sons and none of her daughters, the trait is said to be
b. X-linked recessive.
The pattern of inheritance most commonly expressed by blood group genes is
c. Autosomal codominant.
What is the Landsteiner rule
“you only make abs against antigen you lack”
Define what a chromosome is
a structure within the cell’s nucleus that transmits genetic information
Define what an autosome is
Any chromosome that is not a sex chromosome
Define what a sex chromosome is
X and Y, only has 1 locus, only carries sex genes
Define what a gene is
the portion of a chromosome that determines a trait, a unit of inheritance
Define what a locus is
the position occupied by a gene on a chromosome
Define what an allele is
1 of 2+ different genes that occupy a specific locus on a chromosome
How many alleles per parent is seen in codominance
one per parent
Define what a trait is
characteristic that is inherited, observed expression of the gene
Define what gene interaction is?
genes located at distant loci interact to produce a trait
Define genotype and phenotype
genotype- an individual’s genetic makeup
phenotype-characteristics that are evident from the results of test or direct observation
Define cis and trans
cis: 2+ genes on the same chromosome of a homologous pair
trans: 2+ genes on opposite chromosomes of a homologous pair
True or False: All antigens exhibit dosage
False
Which of the following RBC antibodies are naturally occurring? which are immune based? Anti-A Anti-B Anti-AB Anti-D Anti-K
Anti A,B and AB- natural
Anti-D and K- immune based
Define Complete vs incomplete antibodies
complete-agglutinating
incomplete-non agglutinating
What is the phase that lag is reffering to
inductive phase, initial exposure to antigen
What are the main characteristics of the log phase
antibody production is occurring, turns stable into plateau
Which immune response has more IgM proportionally? Primary or secondary
Primary where there are almost equal amounts of IgM vs IgG , in secondary there is way more IgG than IgM,
Which RBC antigens are glycolipids
ABO, lewis P1
Which RBC antigens are glycoproteins
HLA
Which RBC antigens are lipoproteins
HBsAg
