Immunology Final Exam

how long does B-cell maturation from an HSC to a mature B cell take?

1 to 2 weeks

the percentage of developing T cells that survive positive selection is approximately

2%

SHM and CSR are both dependent on the activity of which of the following enzymes?

AID

which of the following do you expect would be actively functioning in a B cell that had migrated to a germinal center?

AID

which cell type can activate a memory T cell?

B cell; dendritic cell; macrophage

what does CD45R+ cells represent?

B cells

all of the following are true regarding B-cell development except

B cells, like T cells, are MHC class restricted

the receptor for CTLA-4 on APCs is ________. when CTLA-4 on a newly activated T cell (not a regulatory T cell) binds to its receptor on APCs, the T cell _______.

B7-1 (CD80) or B7-2 (CD86); stops proliferating

which of the following constitutes the critical survival cytokine for B cells in the secondary lymphoid tissue cortex?

BAFF

which of the following is required for T2 B cells to become mature B cells?

BAFF

which of the following can be directly activated as a soluble protein in the microenvironement surrounding a pathogenic cell?

C3

which of the following can be directly activated s a soluble protein in the microenvironment surrounding a pathogenic cell?

C3

Of the molecules listed, which can be considered the key molecule in complement pathways?

C5 convertase

which of the following is the most potent anaphylatoxin produced during the complement cascade?

C5a

which of the following molecules provide costimulatory signals to naive T cells?

CD28

which of the following does not induce apoptosis of the target?

CD28 on CTL binding to B7 on target cell

which of the following molecules would double-negative T cells fail to express?

CD4

what is currently the best explanation for what determines whether a T cell develops into a CCD8+ T cell or CD4+ T cell?

CD4 or CD8 expression is determined by the strength and duration of the TCR/MHC interaction

which factors onto surfaces of B cells and T cells, through their interaction, are required to allow germinal center formation to occur?

CD40 and CD40L

activated Th cells signal to B cells to initiate their activation program via which of the following?

CD40L on the T cell to CD40 on the B cell

match the molecule with the region of the cell it is used to label:

CFSE- plasma membrane PKH67 dye- used to determine if a gene is being transcribed PCR- used to determine if a gene is present in a chromosome

which molecule is most closely associated with inhibitory responses to antigen?

CTLA-4

match the treatment with the correct molecule

CTLA-4 agonist- would likely decrease activity of alloreactive T cells CD28 agonist- would likely increase activity of allorective T cells

CTLA-4 is a costimulatory receptor on T cells that belongs to the same family as the CD28 costimulatory receptor. however, CTLA-4 is antagonistic to CD28. which of the following could be a functional advantage of CTLA-4 expression within the immune response?

CTLA-4 limits the immune response of Tc and Th cells after an infection has been cleared.

match the number with the correct description

Cell A- dendritic cell Cell B- activated T cell molecule 2- CRACC molecule 4- CD28

if CD4 needed to be added to the image, CD4 would be drawn on _____ and the cell would be a ______.

Cell A; helper T cell

(Bates) the research suggests that _____ ______ the inflammation that occurs during _____.

DHA; inhibits; SLE

which of the following represents the earliest stage in T cell development

DN

receptors that bind the constant regions of antibodies are known as

Fc receptors

you have consumed a salad contaminated with Salmonella enteric, which typically causes a self-limiting, gastrointestinal disease in humans. based on this information, which immune organ is most likely to first recognize and mount a response against the pathogen?

GALT

which of the following is the pluripotent stem cell that gives rise to all blood cells?

HSC

bonds formed between the T cell and a dendritic cell are relatively weak. which of the following help to strengthen this association so that a T cell can see which antigen is being presented by a dendritic cell?

ICAM-1/LFA-1

(McLamb) you are a new member of the lab and you'd like to perform additional experiment to test the effect stress has on the inflammation. what is the measurement that could be obtained in the future experiments that you would expect the level to increase in early wean pigs? which technique would you use?

IFN-beta; sandwich ELISA

which of the following is not usually induced in response to TLR signaling?

IL-4

(Bates) you are a new member of the lab and you'd like to perform additional experiments to test the effect of DHA has on SLE. what is the measurement that could be obtained in the future experiments that you would expect the level to decrease in SLE patient treated with DHA?

IL-6

this picture represents general components of cell signaling pathways associated with transmembrane receptors. based on what you learned about CRACC, match the proteins/regions below with the correct description.

ITSM motifs- if arrow 1 is pointing to CRACC the protein that arrow 2 is pointing to represents SH2 domain- the regions represented by the red star in protein 2 is Box 4- the enzyme SHIP would most likely inhibit the process indicated by EAT-2- if box 1 is pointing to the CRACC molecule what is the name of the regions represented by the yellow bars?

choose the most likely y-axis label for the graph below is group A represents patients who lack poly Ig receptor and group B represents patients who express the poly Ig receptor

IgA in mucus

mature naive B cells express high levels of ____ on their cell surfaces

IgD

mature naive B cells express high levels of _____ on their cell surfaces.

IgD

deficiency in CD40L on T cells can cause immunodeficiency, resulting in decreased numbers of circulating _____

IgE

some of the cytokines secreted by Th2 cells signal B cells to produce __________ which helps in the destruction of parasites.

IgE

if a patient has low levels of IL-4, or an absence of IL-4, what antibody isotope would most likely decrease?

IgG/IgE

which of the following is capable of undergoing successive rearrangements to prevent the formation of auto reactive lymphocyte receptors?

IgLk

which of the following immunoglobulin isotope is the most efficient at initiating a complement fixation cascade?

IgM

which of the following immunoglobulin isotopes is the most efficient at initiating a complement fixation cascade?

IgM

why is IgM able to form large polymers?

IgM has low affinity and benefits from having a large number of binding sites

considering the effects of EEP reported int eh research article, which of the following would be least likely y-axis label for this graph?

IkB bound to NFkB

(McLamb) the measurement that was not taken in the study was

Il-1

if a host cell has the ligand for _____, then the host cell is less likely to be killed by a NK cell

KIR2DL1

when either self or foreign proteins are digested by the proteasome, the peptides produced from those proteins are more likely to be presented on

MHC I molecules

the TCRs on the surface of the T cell, which are identical (usually), determine the antigen specifically of an individual T cell. thus, to detect antigen-specific T cells, you need a molecule that will bind to the TCR. to detect an influenza specific CD8+ T cell, you would therefore need

MHC I molecules containing influenza peptides

which of the following treatments would most likely inhibit activation of CD4+ T cells and have little/no effect on CD8+ T cells?

MHC II antagonist

CD4+ t cells recognize

MHC class II peptides

Which of the following adapter proteins activate the NKkB pathway?

MyD88

(Sittisart) you are a new member of the lab and and you'd like to perform additional experiment to test the effect of EEP. Based on the knowledge you have about Eep, what measurement would give you the following graph?

NFkB in nucleus

human cells lining the upper respiratory tract are expressing abnormal levels of surface MHC proteins due to a developing viral infection. which cell type listed below is most likely to recognize the cells as infected based on altered MHC levels?

NK cells

how can receptors of the innate immune system, such as PRRs, be considered both specific and general?

PRRs recognize molecules shared by groups of pathogens, not those unique to a species or strain. for example, many bacterial pathogens contain flagella, which would all be recognized by TLR5. however, bacterial pathogens lacking flagella will not be recognized by TLR5.

which of the following is the correct relationship? ____ on ____ recognize _____ on _______.

PRRs; macrophages; PAMPs; pathogens

which enzyme is required to initiate process of VDJ recombination?

RAG

which of the following DNA/protein complexes would you expect to find in a cell undergoing receptor editing?

RAG/VJ

what would be the most accurate y-axis label for the graph shown if group B represented double-negative thymocytes and group A represented double positive thymocytes?

RAG/VJ copmlex

how does allelic exclusion prevent multiple heavy-chain rearrangements from occurring in pre-B cell?

RAG1 and RAG2 are down regulated, and TdT activity is lost so that no additional heavy chain rearrangements may take place

how does allelic exclusion prevent multiple heavy-chain rearrangements from occurring in pre-B cells?

RAG1 and RAG2 are down regulated, and TdT activity is lost so that no additional heavy-cain rearrangements may take place

what introduces single-strand between V(D)J coding sequence and heptameter RSS?

RAG1/2

what recognizes nonuser RSS to begin lymphocyte receptor rearrangement?

RAG1/2

what does the RAG 1/2 enzyme complex bind to at the start of the V(D)J recombination process?

RSS

different effector functions of antibodies depend on the isotope of antibodies and the receptor they bind to. which of the receptor-ligand interaction is correct?

RcRn-IgG

which of the following cell types are lymphocytes?

T cell

of the cells listed below, which one represents the most developed B cell?

T2 B cells

a number of stains of the bacteria Salmonella enteric contain flagella and can invade human cells. based on figure 4-6, which TLRs are most likely to be used to recognize such strains?

TLR5 and TLR9

which enzyme adds new nucleotides to chromosome that are not present in germline DNA sequence?

TdT

what would be the most accurate y-axis label for the graph shown if group A represented pre-B cells and group B represented pre-B cells?

TdT/VDJ complex

choose the most likely y-axis label for the graph below. Group A (low) represents pro-B cells and group B (high) represents pre-B cell?

TdT/VJ activity

interferon-gamma is secreted by ____ and activates ____.

Th1 cells; macrophages to phagocytose

I heavy chain genes, what are the gene segments?

V, D, J

which of the following cell types is least likely to be killed by a NK cell?

a bacterial cell

the top picture most likely represents a chromosome in

a cell that lack RAG enzyme

which of the following cells is most likely to survive selection int he thymus?

a cell with a TCR that has low affinity for the peptide/MHC complexes in the thymus

which of the following would you predict to result in decreased susceptibility to septic shock?

a mutation in TLR4

LPS tolerance is not characterized by

a positive feedback loop

considering how C3 and C5 are activated, which of the following treatments would most likely inhibit their activation?

a protease inhibitor

an electrophoretic mobility shift assay determines if

a protein is able to bind to a specific nucleotide sequence

which of the following correctly describes an ELISA? all correct answers must be selected to receive full credit.

a standar curve can be used to determine concentrations of a molecule in a sample, providing quantitative data; uses antibodies with enzymes attached; uses antibodies to bind to a specific target

the pathogen used to infect the pigs was

a strain of E coli that has a toxin that causes diarrhea and is a major cause of sickness and death in children worldwide

in negative selection, cells that receive _____ signal through their antigen receptors die.

a strong

which of the following is not an effector function of antibodies?

activation of cytotoxic T cells

the fas ligand (FasL) represents a key signaling pathway among cell mediated effector cells. what is the function of the Fas-FasL signaling pathway?

activation of the Fas-FasL signaling pathway triggers apoptosis

what is the best description of the following data?

active transcription of TNF

C-reactive protein is a(n)

acute phase response protein

if a human were unable to produce lymphoid progenitor cells, predict which part of the immune system would be most greatly impacted?

adaptive immunity

several proteins must work in a coordinating fashion to achieve V(D)J recombination. which of the following is the function of TdT

add non-templated nucleotides to the V-D and D-J joints of Ig heavy chains

which of the following are associated with damaged or dead cells?

all of these: low CD47; altered carbohydrates; cell surface annexing I; lysophosphatidic acid

which of the following complement fixation pathways can be initiated by a soluble C3 converts?

alternative

regarding Myasthenia Gravis, which of the following statements is true?

an antagonistic IgG antibody is binding to the ACh receptor blocking it for stimulation, leading to paralysis

what is the effector molecule of humoral immunity?

antibodies

which of the following is not entirely a response of the innate immune system?

antibody mediated complement activation

virally infected host cells are tagged with antigen-antibody complexes. these complexes recruit NK cells that trigger apoptosis in the infected host cell. this is an example of

antibody-dependent cell mediated cytotoxicity

what is the component of immune complexes?

antigen + IgG

which most likely accurately represents the general order of the steps to antigen presentation?

antigen acquisition, antigen breakdown into peptides, encounter of peptides with MHC molecules, binding of peptides to MHC molecules, and display of the peptide-loaded MHC molecules on the cell surface

BALF would most likely be collected if you were studying

asthma

in cytokine activated cells, STAT proteins are more likely to

be bound to DNA; form dimers

why are many opsonins multimeric?

because they bind repeating structures on pathogen surfaces

which of the following would not be included when examine a person's exposome?

being born with a p53 mutation

the CTLA-4 expressed by tregs is used to

bind to costimulatory molecules on dendritic cells and block costimulation of naive T cells

B lymphocytes are made in the

bone marrow

all blood cell in an adult human can trace their ancestry to which compartment within the body?

bone marrow

all blood cells in an adult human can trace their ancestry to which compartment within the body?

bone marrow

committed lymphocyte progenitors originate in the

bone marrow

where fo B and T lymphocytes originate?

bone marrow

where is the least likely location of a follicle?

bone marrow

which of the following is the correct pathway for B cell development, activation, and differentiation?

bone marrow -> spleen -> GC -> bone marrow

V-J rearrangement occurs in

both B and T cells

deficiency in RAG1 and/or RAG2 can affect the proper development of which of the following cell types, resulting in deceased numbers of circulating cells of those types?

both B and T cells

deficiency in RAG1 and/or RAG2 can affect the proper development of which of the following cell types, resulting in decreased umbers of circulating cells of those types?

both B and T cells

which of the following is required to Tell activation?

both antigen-specific TCR binding to MHC peptide and interaction with CD80, CD86, or ICOS-L are correct

ELISPOT assays

both involve the use of capture antibodies and are used to detect individual cells

peptide binding diversity is increased by

both multiple MHC alleles in the population and multiple homologous MHC genes in the genome

how do natural killer cells kill their targets?

by inducing apoptosis

in the research described int eh article by Sittisart et al., which of the following serves as a positive control?

cells treated with LPS

which of the following processes does not require DNA recombination?

changing the variable region of activated, mature B cells

which of the following complement fixation pathways can be indirectly initiated by a B cell?

classical

immature B cells int eh bone marrow that are found to bear self-antigen reactive BCRs undergo which of the following?

clonal deletions light chain receptor editing; and development of anergy

what characterizes the pro-B-cell stage in B-cell development?

commitment to the B-cell lineage

all of the following are functions of Th1 cells except

contribute to autoimmunity

CD8+ T cells exposed to MHC class I peptides are

cytotoxic T cells

IL-10 has the opposite effect of TNF, if cells are treated with IL-10, the most likely effect would be a/an

decrease in nuclear NF-kB

compared to cells treated with TNF, if cells are treated with IL-10, the most likely effect would be a/an

decrease in nuclear NF-kB

multiple negative feedback mechanisms were discussed int he textbook to control inflammation. which of the following mechanisms are not used to control inflammation?

decreased production of IkB

which of the following would you predict to result from a mutation in TLR4 that prevents binding to LPS?

decreased susceptibility to septic shock

Th17 cells are involved with all of the following except

delayed-type hypersensitivity

which of the following is most likely to stimulate a memory T cell?

dendritic cell; memory cell; B cell

of you wanted to measure the level of CRP in a sample, you would use

direct (sandwich) ELISA

which of the following best describes the differences between types II and III hypersensitivity reactions?

direct recognition of cell-surface antigens by antibodies in type II reactions versus deposition of improperly cleared antibody-antigen complexes in type III reactions

M cells are specialized

epithelial cells that transport antigens for the lumen of the intestines to leukocytes within the gut lymphoid tissue

what characterizes the pre-B-cell stage in B-cell development?

expression of the pre-BCR; rearrangement of light chain genes; proliferation; both expression fo the pre-BCR and proliferation

heavy chain polypeptides are either called kappa or lambda chains.

false

true or false: the innate immune responses work largely independently of one another.

false

(Bates) int eh research paper discussed in class, which of the following was considered to be anti-inflammatory?

fish oil

Mature T cells are similar to mature B cells since mature T cells

have TCR genes that were produced by random rearrangement of gene segments

if mice lacked CTLA-4, what would you expect to find in the mice?

high levels of T cells

choose the most likely label for the graph below. group A (low) represents a test tube with mast cells that lack FceR and group B (high) represents a test tube with mast cells that express FCeR. assume IgE binding to antigen have been added to the test tubes

histamine

CTLs. mediate a powerful and lethal immune response to infected host cells. which of the following steps is not involved with CTL activation and function?

histamine is released from cytoplasmic granules, recruiting macrophages to the site of infection

Fab

if an antibody was attached to a virus, this region would be specifically binding to the virus; this region is always different between IgG and IgE; this region contains the variable regions of the heavy and light chains

this type of cell will leave the bone marrow and complete maturation in the spleen.

immature B cell

where would you most likely find a TLR that recognizes viral DNA?

in the end-some/lyosome

where would you most likely find a TLR that recognizes RNA?

in the endosome/lysosome

which of the following is not an effect of C3a and C5a binding their receptors on leukocytes?

increased vascular permeability via induction of TNF and IL6 secretion; induction of degranulation by granulocytes; and increased smooth muscle contraction to aid in delivering immune cells and molecules to the site of infection

the function fo SHM is best described by which of the following statements?

increasing the affinity of immunoglobulins for their antigen

in order to measure regulatory R cells, FoxP3+ cells are often measured. FoxP3 functions by

increasing transcription of anti-inflammatory genes

which of the following statements best differentiates innate and adaptive immune responses are not required.

innate responses are stronger during the primary and less important during the secondary response, whereas adaptive responses are less robust during primary responses and stronger during secondary responses

the difference between an ELISA and an ELISpot is that only one of the assays (not both assays)

involves adding cells to a well

what defines an exogenous antigen?

it is generated outside of the cell then taken into the cell by endocytosis

what defines an endogenous antigen?

it is generated within the cell

NK cells are more likely to be activated by a cell line that

lacks MHC class I molecules

at what stage of development does a B cell begin to express a pre-B-cell receptor?

late pre-B cell

what is the final step of the V(D)J recombination process?

ligation by DNA ligase IV and NHEJ proteins

the samples used in the Sittisart study was

macrophages

of the cells listed below, which one represents the most developed B cell?

mature B cells

memory T cells, effector T cells, and naive T cells share several characteristics. which of the following description could only be said of memory T cells?

memory T cells are activated by an APC

a bacterial pathogen has breached the skin barrier of a human. this is the first time this human host has been exposed to this particular pathogen. which statement is not true regarding the situation?

memory T cells will aid in pathogen recognition and response

which of the following is considered negative control in the research we discussed in class?

mice prone to lupus

the research described in the article by Melissa Bates et al., was performed using

mice that spontaneously develop lupus like symptoms over time

choose the most likely y-axis label for the graph below is group A represents the test tube with cells that express FcRn and group B represents a test tube with cells that lack FcRn. assume both IgG and IgA have been added to the test tubes containing the cells.

monomeric IgG in the supernatant

when performing an ELISA, if the OD measurement is higher in a sample, that sample contains:

more detecting antibodies attached to antigens compared to other samples

which of the following IgH chains is not produced as a result of CSR?

mu

the first immunoglobulin isotope produced during the course of a primary immune response contains which of the following heavy chains?

mu (u)

which lineage of immune cells constitutes the first line of defense against an infection?

myeloid

which cell can differentiate into the greatest variety of cells during hematopoiesis?

myeloid progenitor

what term best describes a selection process against those cells whose T cell receptors bind too strongly to self-peptide/MHC combinations?

negative selection

________ describes the action of antibodies whereby antibodies bind to a pathogen and prevent the pathogen form interacting with cell receptors.

neutralization

when the skin becomes inflamed, which of the following occurs?

neutrophils move from the blood into the interstitium

which of the following best explains the timing of the classical pathway of complement fixation, relative to the other pathways of complement fixation, against a pathogen in an individual who has never been exposed to said pathogen?

no target for C1 exits on the surface of the pathogen in the earliest stages of the response to it

in flow cytometry, in addition to fluorescent markers, forward (FSC) and side (SSC) scatter are measured, and

none of the answers are correct

C-reactive protein is a(n)

opsonin

_______ describes the recruitment of phagocytic cells by the Fab portion of an antibody.

opsonization

(McLamb) which group of pigs would be classified as living in the environment with the highest stress?

pigs weaned at 16 days of age and infected with a pathogen

which group of pigs would be classified as living in the environment with the highest stress?

pigs weaned at 16 days of age and then infected with a pathogen

V-J recombination occurs during which phase of a B cell's development?

pre-B cell

at what stage of development does a B cell begin to express a B-cell receptor with surrogate light chains?

pre-B cell

which of the following is used to generate diversity in the antibody repertoire?

presence of multiple variable gene segments that can be assembled in multiple different combinations; addition of N nucleotides that are not encoded in the germ line; exonuclease trimming of excess nucleotides at variable segment junctions; ability to pair a single heavy chain with different light chains, so as to avoid generation of auto reactive antibodies

a positive feedback loop would be useful in all of these scenarios except

preventing an overreaction to a stimulus

what is the function of bone marrow stroll cells with respect to B-cell development?

prevents self-antigens to B cells for negative selection

V-DJ recombination occurs during which phase of a B cell's development?

pro-B cell

what characterizes the pre B cell stage in B cell development?

proliferation; expression of the pre BCR; both expression fo the pre-BCR and proliferation; rearrangement of light chain genes

CFSE is used to measure ________ of cells. this process is occurring __________ in cells as the levels of CFSE decrease.

proliferation; more

which of the following defenses is most likely to protect a plant form a microbial pathogen?

reactive-oxygen species

which of the following accounts for allelic exclusion in rearrangement within the IgH locus?

rearrangements only occurs on one homolog at a time, and once one homolog has successfully rearranged, the other is methylated to produce heterochromatin

in an inflammasome has formed in a cell, the cell is most likely

secreting interleukin 1 (IL-1)

which of the following best describes chemokines?

soluble proteins that recruit specific cells to an area

where do developing B cells complete their maturation through the T1 and T2 stages?

spleen

what types of cells are good targets for natural killer cells and why?

stressed self cell because they have altered class I MHC

signaling through the pre-TCR occurs as a result of

successful assembly of the pre-TCR

which of the following processes is most likely occurring in germinal center B cells?

switching from IgM to IgG

within light chain recombination process, what are the results of hairpin cleavage?

symmetrical opening leading to a blunt end; asymmetrical openings leading to 3' and 5' overhangs; asymmetrical opening leading to a 5' overhang; asymmetrical opening leading to a 3' overhang

licensing on an NK cell refers to

testing an NK cell to ensure that it will not target healthy host cells

Fc-receptor molecules tend to have short cytoplasmic tails. how does this influence signaling events within the Fc-receptor cell?

the Fc-receptor is dependent upon a coreceptor (ITAM or ITIM) that will trigger signaling events within the cell

the difference between NK cells and T lymphocytes is:

the amount of time it takes fo their level to increase in a patient with a viral infection; their receptors that bind to MHC I molecules

an example of ectopic lymphoid tissue would be follicles located in

the kidneys

if you suspect your patient may have lupus, what would you measure?

the level of anti-dsDNA IgG

the y-axis label of ELISA data is often "O.D.". what does this refer to?

the light emitted from the enzyme/substrate reaction

which of the following best describes the patient with non-functional AID?

the patient will only have IgM antibodies

what is the best definition of immunity?

the state of being resistant to reinfection with a pathogen

(Bates) the main difference between immunohistochemistry and ELISA is?

the type of sample used

the human MHC locus is one of the most polymorphic regions of the genome. what does this mean?

there are many different alleles of these genes

what happens to auto reactive cells that escape the thymus

they attack self-tissues; they can be rendered anergic; they negatively regulate other auto reactive cells; they require TCR ligation and costimulation to be activated

most people are exposed to DHA when

they eat fish

NK receptors are encoded in the germ line and are described by all of these except

they recognize likely pathogen

the results of a gel electrophoresis are shown in the picture. you must choose all correct statements regarding the gel to receive credit.

this gel electrophoresis was performed to complete an EMSA; sample 1 contains proteins attached to DNA

Fc

this region contains the constant of the heavy chain; this region determines the isotope of the antibody; if an opsonizing antibody to a virus, this region could bind to receptors on a phagocytic cells and then signal for the virus/antibody complex to be phagocytosed

naive CD4+ and CD8+ T cells leave the _____ and enter circulation.

thymus

which of the following is a potential cause of chronic inflammation?

tissue damage; intestinal commensal microbiota components; infectious agents; obesity

the role of cell mediated immunity is

to find and eliminate cells infected with intracellular pathogens

follicular helper T cells are a recent discovery in the helper T cell lineage. what is the primary role of Tfh cells?

to help B cell development in germinal centers

what is the function of a memory T cell?

to provide an almost immediate response upon subsequent exposure to a specific pathogen

two different B cells can have antibodies that have the same variable regions and different constant regions.

true

hypersensitivity reactions to cell surface antigens via IgG or IgM are classified as which type?

type II hypersensitivity

what types of cells are good targets for natural killer cells and why?

virally infected cells because they have low levels of class I MHC

put the following events in the correct order demonstrating the events that occur after a virus has entered the respiratory tract or digestive tract.

virus binds to TLRs on epithelial cells --> interferon alpha is secreted --> NK cells divide and differentiate --> NK cells induce apoptosis of infected cells

ELISA

y axis label- ng/ml performed in liquid sample uses antibodies to detect specific molecules

Immunohistochemistry (IHC)

y-axis label - % stained tissue performed on tissue biopsies uses antibodies to detect specific molecules