Immunodiagnostics Exam 2

Natural Immunity Chart

Infection

Vaccination

Passive/Adaptive immunity

Colostrum

serum or plasma

vivo

plasma cell

basophil

reactive lymphocyte

monocyte

lymphocyte

WBC Differential Relative Reference range

Neutrophils 50-70%

Lymphocytes 20-40%

Monocytes 2-9%

Eosinophils 0-4%

Basophils 0 - 2%

Which region of the immunoglobulin molecule can bind antigen?

Fab Region

Which immunoglobulin appears first in the primary response?

IgM

Which is characteristic of IgG?

-predominant Ig in humans (70-75% of the total serum Ig)

-longest half life (23 days)

-four major subclasses—IgG1 66%, IgG2 23% , IgG3 7%, IgG4 4%

-monomer with a molecular weight of 150,000 Daltons

-sedimentation of 7S

-Binding complement

• -lead to inflammation/ destruction of foreign cells

• -IG3 is the most efficient, followed by IgG1

-can cross the placenta

-provide immunity for newborns

-opsonization

-neutralizes toxins and viruses

-participates in agglutination and precipitation reactions

-macrophages, neutrophils, monocytes have receptors specifically for IgG

-IgG1 and IgG3 are practically good at initiating phagocytosis

-has a high diffusion coefficient that allows it to enter extravascular spaces (7s)

The primary response is characterized by:

Long lag phase, a slow increase in antibody, and a short-lived response

Which immunoglobulin appears in the highest titer in the secondary response?

IgG

The antigen specificity of a B cell is determined:

Shape of the variable region

The idiotype of an antibody is located on which region?

Located at the amino-terminal ends of both L and H chains

All polymeric but not monomeric immunoglobulins are characterized by:

J chain

Kappa or lambda light chains

Both kappa and lambda light chains are found in all five classes of immunoglobulins, but only one type is present

-found on constant region

-Only VJ genes are present

-each contain 200-220 amino acids

-kappa light chain is found on chromosome 2

-lambda light chain is found on chromosome 22

Variations in immunoglobulin structure that occur because of the use of different constant region domains are known as:

Isotypes

The ability of an antibody to opsonize is located in which region?

Fc region

What products are the result of papain being used to cleave antibody molecules?

Fc Fragments

Fab Fragments

Which is a characteristic of IgM?

· half life is about 6 days

.accounts for between 5% and 10% of all serum immunoglobulins.

· Functions: complement fixation, agglutination, opsonization, neutrilization

· found mainly in intravascular pool

· first to appear after antigenic stimulation & first to appear in infants

· No memory cells for IgM

Which of the following pairs represents light chains of antibody molecules?

Kappa (κ) chains and lambda (λ) chains (200-220 amino acids)

Identify the true statement about the anamnestic response versus the primary response.

Primary response is characterized by a long lag phase, slower increase in antibody, and short-lived response.

Anamnestic (second) response is distinguished by short lag time, more rapid rise in antibody and higher serum levels for longer period of time

Which immunoglobulin can cross the placenta?

IgG

The valence of an IgG antibody molecule is:

2

The receptor for antigen on a mature B cell is:

IgM and IgD

The region of an antibody molecule that exhibits the greatest variability from antibody to antibody is known as the:

Variable Region

Somatic mutation of immunoglobulin genes accounts for:

High affinity (affinity maturation)

Identify the statement about monoclonal antibodies that is true.

Derived from a single parent antibody-producing cell that has reproduced many times. Used for vitro diagnostic testing. Has multiple epitopes that stimulate B cells.

IgA in secretion's has a valence of

4

Which option represents an isotype of a heavy chain?

Epsilon

IgD is produced by:

Unstimulated B-lymphocyte or differential splicing of RNA transcript.

Select the statement about secondary response to an antigen that is true.

Equal amounts of IgG and IgM are produced. IgG is increased 100 fold to 1,000 fold. IgM increases 100 fold. Short lag time

The combination of a plasma cell fused to a myeloma cell is called a:

Hybridoma

Which of the following statements about coding for antibody molecules is true?

-chromosomes contain no intact immunoglobulin genes, only building blocks from which genes are assembled

-H chain genes are found on chromosome 14, kappa chain genes on chromosome 2, and lambda chain genes on chromosome 22

-genes cannot be transcribed without gene rearrangement

Immunoglobulins are grouped into classes on the basis of similarities in:

Constant regions of their heavy chains

What is the main function of IgD?

Plays a role in B-cell activation and B-cell maturation

Bence-Jones proteins are identical to:

L chains

Which region determines whether an immunoglobulin molecule can fix complement?

CH

A Fab fragment consist of :

1 L chain and ½ of an H chain held together by disulfide bonding

Identify the main purpose of the secretory component of IgA.

-Transports across endothelial cells

main function of secretory IgA is to patrol mucosal surfaces and acts as a first line of defense

In serum electrophoresis conducted at pH 8.6, which protein group migrates the fastest?

Albumin

The antibody found on B cells that is thought to be involved in B-cell maturation is:

IgD

The theory that lymphocytes are preprogrammed to respond to a particular type of antigen best describes:

Colonal selection hypothesis

In serum protein electrophoresis, which band contains the immunoglobulins?

Gamma Band

Where on an antibody molecule does combination with antigen take place?

Hypervariable region

Which antibody is found mainly as a dimer in mucosal secretions?

Secretory IgA

IgG subclasses differ from one another in the number and position of:

Hinge regions

Of all IgG subclasses, IgG3 has the largest hinge region, making it:

Most efficient at binding complement proteins

All of the following are TRUE regarding the anamnestic response except

-antibody titer is lower than in the primary response

-Contains more IgG; shorter lag phase; due to memory B and T cells; much more rapid rise in antibody that stay in serum for a longer period of time

How does the DNA in a pre-B cell differ from germline DNA?

The V, D, and J genes have been successfully rearranged on the chromosome coding for the heavy immunoglobulin chain.

In a PreB cell, the heavy chain gene has been randomly recombined already; there is also combination of the heavy chain with Ig-alpha and beta and the surrogate chains

Which complement component is found in both the classic and alternative pathways?

C3—key intermediate in all pathways

Which of the following can activate the alternative complement pathway?

C3b

Select the test that could be used to determine whether a patient has a specific deficiency in C3.

radial immunodiffusion

Chemotactic and anaphylactic factors are produced by proteolytic cleavage of:

C5a and C3 (C3a and C5a)

The alternative and classical pathway C3 convertases are destabilized as a means of

downregulating complement function. One molecule that performs this function is:

Membrane Cofactor Protein (MCP)

Which of the following is the correct order of activation of complement in the lectin activation pathway?

MBL, C4, C2, C3

Which complement receptor is involved in mediating phagocytosis?

CR3

The C3 convertase of the alternative pathway of complement activation is:

C3bBb

Which complement receptor is found on mature B cells?

CR2 (CD21)

A patient has an abnormal alternative pathway activation pattern. Which of the following complement proteins should be assessed to further investigate the problem?

C3

The C5 convertase of the classical pathway of complement activation is:

C42a3b'

Identify the condition that would result from a deficiency in complement component C2.

Immune complex disease

Lupuslike syndrome; recurrent infections; atherosclerosis

Kidney glomeruli can become obstructed with immune complexes as a result of:

Inadequate C3b opsonization

Which complement factor polymerizes to cause lysis of a foreign cell?

C9

Lack of the complement inhibitor C1INH results in which disease?

Hereditary angioedema

C4 binding protein (C4BP) acts in association with which factor to inactivate C4b?

Factor 1

In the alternative pathway, C3 and C5 convertase are stabilized by which of the following?

Properdin

Which factor must be associated with factor H to inactivate complement components?

Factor1

Which factor helps to dissociate C3b from red blood cells?

DAF

Formation of the membrane attack complex (C5b-C9) is stopped by which factor?

S protein (vitronectin)

Dense deposits of C3 breakdown products can accumulate in the kidneys because of:

Autoantibodies bind to C3bBb

What reagent is present in a CH50 assay and absent in an AH50 assay?

Calcium

A decreased CH50 and a decreased AH50 would indicate a low amount of which of the following complement components?

Decrease in components of the classical pathway only

Identify the alternative pathway trigger.

Fungal cell wall

Complement components are completely destroyed if a specimen is

Heated (heat liable)

Which of the following is TRUE regarding the C3 convertase in the classic complement pathway?

C3 convertase is part of the activation unit. C4b2a is formed which binds to C3 to form c5 convertase

Which of the following is TRUE regarding the alternate pathway of complement activation?

It is an amplifies loop for classical or lectin pathway

Can be activated by any pathogen

Involves C3 C5-C9, factors B, D and P

All of the following conditions have been associated with deficiencies in complement regulatory proteins except

Paroxysmal Nocturnal Hemoglobinuria (PNH)

- Hereditary Anigioedema (HAE)

- Hemolytic Uremic Syndrome (HUS)

- C3 glomerulopathies (C3G)

Most common deficiency is C2.

C3 deficiency is the most serious.

Deficiencies in C5-C8

A specimen has a reduced total hemolytic complement as measured by CH50. When individual components were measured, total C3 was very reduced, but total C4 was within normal limits. How can these results be best explained?

The reduced hemolytic response indicates a decrease in any factor deficiency can lead to live issues in the body. The C3 that is very reduced must be from the alternative pathway since C4 was within normal limits and is only for classical and lectin pathway. Alternative pathway does not have C4. Alternate pathway is the reasoning.

If complement CH50 is decreased and complement AH50 is normal in a specimen, the specimen may be deficient in factor(s)

C1, C2 OR C4

In the complement fixation test, the presence of an antibody/antigen reaction is detected because

The complement is bound and is unavailable to lyse sensitized red blood cells

A complement fixation test is done to see if a specimen contains antibodies to rubella virus. A control negative for antibodies and a control positive for antibodies are run, and the sensitized sheep cells are tested alone with no specimen or complement added. Which of reactions below is correct if the specimen does contain antibodies?

If hemaguttination does not occur, patient has antibodies against rubella virus

If sheep RBCs do not lyse, patient has antibody it is a positive test

What is measured in the CH50 assay?

Measures the function of the classical pathway

What is the function of IL-17 in the innate immune response?

What is a cytokine storm?

An umbrella term for clinically heterogeneous set of life-threatening syndrome characterised by immune dysregulation and uncontrolled inflammation that leads to unremitting fevers, cytopenias, coagulopathy, multi-organ failure and death.

What is one of the main activities of IL-4?

Generates Th2 cells

Which type of cytokine acts as the best defense against gram-negative bacteria?

Which cytokine is involved in natural immunity?

What is the main target of IL-3?

What is the function of TGF-beta?

to regulate diverse cellular processes such as cell proliferation, differentiation, apoptosis, cell plasticity and migration.
It also plays a pivotal role in embryonal development and cellular haemostasis.

Which clinical assay can be used for measuring cytokine concentrations in serum samples?

Microbead assay

The actions of IL-1 and IL-10 are examples of:

antagonism

Which cytokine might be given therapeutically to a patient with severe anemia?

Erythropoirtin

Which of the following cytokines is produced by Th1 cells and is suppressive for Th2?

Which of the following are IL-3, IL-7, and GM-CSF are all involved?

Which of the following cytokines is produced by Th2 cells and inhibits Th1?

IL-10

Which of the following cells synthesizes IL-2?

Which of the following cells produce IFN-gamma?

TH1 cells