ANTIBODIES AND CYTOKINES

a

Who discovered antibody activity in serum by demonstrating that transfer of serum from immunized animals could protect against diphtheria?

• A. Emil von Behring and Shibasaburo Kitasato

• B. Ms. Rothessa Mary Caringal and colleagues

• C. Robert Koch and Louis Pasteur

• D. Elie Metchnikoff and Paul Ehrlich

• E. Edward Jenner and Alexander Fleming

a

During Serum Protein Electrophoresis (SPE), in which fraction/band do the vast majority of immunoglobulins migrate?

• A. Gamma globulins band

• B. Beta globulins band

• C. Alpha-1 globulins band

• D. Alpha-2 globulins band

• E. Albumin band

a

Immunoglobulins are glycoproteins. What is the typical percentage range of the carbohydrate component in these molecules?

• A. 2-14%

• B. 15-25%

• C. 30-45%

• D. 50-60%

• E. 86-98%

a

Question 4

Which proteolytic enzyme breaks peptide bonds in the hinge region of IgG to yield three fragments: two Fab fragments and one Fc fragment?

• A. Papain

• B. Pepsin

• C. Trypsin

• D. Chymotrypsin

• E. Elastase

a

Which cysteine-rich peptide is responsible for holding the five monomeric units of pentameric IgM together?

• A. J (joining) chain

• B. Secretory piece

• C. Hinge polypeptide

• D. Light chain constant region

• E. CH1 domain disulfide

a

What is the normal reference value of IgM in umbilical cord blood?

• A. >20 mg/dL

• B. 120 - 150 mg/dL

• C. >1 mg/dL

• D. 800 - 1800 mg/dL

• E. Undetectable

a

Which cytokine, known as the T-cell growth factor, is synthesized and secreted primarily by T cells?

• A. IL-2

• B. IL-1

• C. IL-3

• D. IL-6

• E. TNF-alpha

a

What is the primary cellular origin of the cytokines belonging to the IL-1 Superfamily?

• A. Monocyte-macrophages and dendritic cells

• B. T lymphocytes and B plasma cells

• C. Osteoblasts and hepatocytes

• D. Epithelial cells and neutrophils

• E. Mast cells and basophils

a

Which cytokine is produced by virally transformed cells, acts as an anti-proliferative factor that induces growth arrest in tumor cells, and down-regulates the inflammatory response when it is no longer needed?

• A. TGF-beta

• B. TNF-alpha

• C. IFN-gamma

• D. IL-6

• E. IL-1B

a

Which colony stimulating factor regulates hematopoiesis and red blood cell production in the bone marrow, and is primarily synthesized in the kidneys?

• A. EPO (Erythropoietin)

• B. G-CSF

• C. M-CSF

• D. GM-CSF

• E. IL-3

b

Humoral immunity is mediated by glycoproteins synthesized by which specific immune cells?

• A. T lymphocytes

• B. B plasma cells

• C. Dendritic cells

• D. Natural Killer (NK) cells

• E. Monocytes

b

Regarding the chemical composition of immunoglobulins, what is the proportion of the polypeptide chain?

• A. 2-14%

• B. 86-98%

• C. 30-45%

• D. 50-60%

• E. 10-15%

b

What is the flexible segment in the heavy chain located between the CH1 and CH2 constant domains?

• A. Carboxy terminal

• B. Hinge region

• C. Variable domain

• D. Antigen binding site

• E. J chain

b

What is the normal reference range for IgM in healthy adults?

• A. 800 – 1600 mg/dL

• B. 120 – 150 mg/dL

• C. 70 – 350 mg/dL

• D. 350 – 400 mg/dL

• E. Undetectable

b

Which of the following values represents the sedimentation coefficient of IgM?

• A. 7S

• B. 19S

• C. 8S

• D. 11S

• E. 15S

b

In IgM, which domain is specified as the site for classical complement pathway activation?

• A. CH1

• B. CH14 (CH4)

• C. CH2

• D. CH3

• E. VH

b

Which subclass of IgG has the largest hinge region, making it the most potent activator of the classical complement pathway?

• A. IgG1

• B. IgG3

• C. IgG2

• D. IgG4

• E. IgG1 and IgG2

b

Which subclass of immunoglobulin A is primarily monomeric and is typically found in human serum?

• A. IgA2

• B. IgA1

• C. Secretory IgA dimer

• D. Colostrum IgA

• E. IgA3

b

The variations of amino acid sequences within the variable domains on both light and heavy chains are referred to as:

• A. Isotypes

• B. Idiotypes

• C. Allotypes

• D. Monotypes

• E. Genotypes

b

Which cytokine from the IL-1 family acts as an endogenous pyrogen, modulating inflammation and inducing fever via the hypothalamus?

• A. IL-6

• B. IL-1B

• C. TNF-alpha

• D. TGF-beta

• E. IL-10

c

The basic, monomeric structure of an antibody molecule consists of how many total polypeptide chains?

• A. Two identical heavy chains

• B. Two identical light chains

• C. 4 (2 identical heavy chains and 2 identical light chains)

• D. 5 monomeric units linked together

• E. 10 binding sites

c

What are the two distinct structural varieties in which immunoglobulin light chains occur?

• A. Alpha and Beta

• B. Gamma and Delta

• C. Kappa and Lambda

• D. Mu and Epsilon

• E. Variable and Constant

c

Pepsin digestion of IgG differs from papain digestion. What fragment(s) are recovered from pepsin digestion that retain antigen-binding activity?

• A. Two individual Fab fragments

• B. An intact Fc' fragment and two separate Fab subunits

• C. A single F(ab')2 fragment composed of two Fab-like subunits

• D. Four individual polypeptide chains linked by disulfide bonds

• E. Three identical fragments called Fab

c

What is the normal reference range of IgG in healthy adults?

• A. 120 – 150 mg/dL

• B. 70 – 350 mg/dL

• C. 800 – 1600 mg/dL

• D. 350 – 400 mg/dL

• E. 800 – 1800 mg/dL

c

Which immunoglobulin is highly susceptible to proteolysis, has an unknown function in serum, and is mainly located on the surface of B lymphocytes to initiate the immune response?

• A. IgM

• B. IgG

• C. IgD

• D. IgE

• E. IgA

c

Which immunoglobulin class mediates allergic/anaphylactic reactions and parasitic infections by binding to mast cells and basophils, causing histamine release?

• A. IgM

• B. IgG

• C. IgE

• D. IgD

• E. IgA

c

Which immunoglobulin variations represent inherited, small, functionally insignificant structural differences caused by amino acid differences in the constant region?

• A. Isotypes

• B. Idiotypes

• C. Allotypes

• D. Xenotypes

• E. Subtypes

c

In the primary antibody response, what is the initial phase during which no antibody is detectable in the serum?

• A. Log phase

• B. Plateau phase

• C. Lag phase

• D. Decline phase

• E. Anamnestic phase

c

Which term is defined as the initial force of attraction that exists between a single Fab site on an antibody molecule and a single epitope on an antigen?

• A. Specificity

• B. Antibody avidity

• C. Antibody affinity

• D. Cross-reactivity

• E. Clonal selection

c

Which cytokine family is primarily responsible for inducing chemotaxis, stimulating the migration of PMNs and mononuclear leukocytes from blood to infected tissue sites?

• A. Tumor Necrosis Family (TNF)

• B. Interferons (IFN)

• C. Chemokines

• D. Transforming Growth Factors (TGF)

• E. Colony Stimulating Factors (CSF)

d

What is the primary function of an antibody molecule?

• A. To act as effector molecules with the complement system

• B. To bind to host tissues to trigger complement opsonization

• C. To trigger clonal deletion of autoreactive plasma B cells

• D. To combine with antigen to neutralize bacterial toxins and viruses

• E. To initiate hematopoiesis in the bone marrow under cytokine influence

d

Each polypeptide chain in an antibody contains compactly folded loops stabilized by intra-chain disulfide bonds. What are these loop structures called?

• A. Chords

• B. Constant terminals

• C. Hinge regions

• D. Domains

• E. Glycoprotein chains

d

Secretory IgA exists as a dimer in mucosal secretions. What is the cellular origin of the secretory piece/component attached to this dimer?

• A. Plasma B cells

• B. Dendritic cells

• C. Macrophage-monocytes

• D. Epithelial cells

• E. Hepatocytes

d

What is the normal proportion of the IgG1 subclass relative to the total serum IgG concentration in humans?

• A. 3 – 4%

• B. 4 – 7%

• C. 23 – 28%

• D. 65 – 70%

• E. 70 – 75%

d

Which antibody class is the most abundant in circulation, has a serum half-life of 23 days, and is capable of crossing the placenta?

• A. IgM

• B. IgE

• C. IgA

• D. IgG

• E. IgD

d

Which of the following is designated as a major anti-inflammatory cytokine that down-regulates inflammatory responses?

• A. TNF-alpha

• B. IL-1

• C. IL-6

• D. IL-10

• E. IFN-gamma

d

Which cytokine is the principal mediator of the acute inflammatory response to Gram-negative bacteria?

• A. IL-2

• B. IL-3

• C. TGF-beta

• D. TNF (Tumor Necrosis Factor)

• E. Erythropoietin (EPO)

d

Which of the following describes a localized paracrine effect mediated by proinflammatory cytokines like IL-1, IL-6, and TNF-alpha?

• A. Induction of fever via the hypothalamus

• B. Release of granulocytes by the bone marrow into the blood

• C. Subjective systemic feeling of being ill

• D. Increased capillary permeability, platelet aggregation, and endothelial adhesion molecule expression

• E. Systemic decrease in body temperatu

d

Which CD4+ T-helper subset is regulated by IL-4 and is primarily responsible for antibody-mediated (humoral) immunity?

• A. Th1 cells

• B. Treg cells

• C. Th17 cells

• D. Th2 cells

• E. Cytotoxic T cells

d

Which anti-inflammatory cytokine is a specific receptor antagonist belonging to the IL-1 family and serves to modulate inflammation?

• A. IL-1B

• B. IL-6

• C. IL-10

• D. IL-RA

• E. TGF-beta

e

What domain composition is characteristic of an immunoglobulin light chain?

• A. Two variable domains and two constant domains

• B. One variable domain and three constant domains

• C. Two variable domains and one constant domain

• D. One variable domain and four constant domains

• E. A single variable domain (VL) and a single constant domain (CL)

e

Which subclasses of IgG are primarily directed against polysaccharide antigens?

• A. IgG1 & IgG3

• B. IgG1 & IgG4

• C. IgG3 & IgG4

• D. IgG1 & IgG2

• E. IgG2 & IgG4

e

What is the normal reference value range for serum IgA in healthy adults?

• A. 120 – 150 mg/dL

• B. 800 – 1600 mg/dL

• C. 350 – 400 mg/dL

• D. 0.1 to 0.6 mg/dL

• E. 70 – 350 mg/dl

e

Which immunological term describes the overall strength of functional combining between a multivalent antibody and its multivalent antigen?

• A. Specificity

• B. Cross-reactivity

• C. Antibody affinity

• D. Clonal selection

• E. Antibody avidity

e

In cytokine biology, which term refers to the ability of different cytokines to activate the same downstream cellular pathways?

• A. Pleiotropism

• B. Autocrine stimulation

• C. Paracrine stimulation

• D. Endocrine stimulation

• E. Redundancy

e

Which cells are the primary producers of interferon-alpha (IFN-α) and interferon-beta (IFN-β), which function to interfere with viral replication?

• A. Monocytes

• B. T cells

• C. Osteoblasts

• D. Hepatocytes

• E. Dendritic cells

e

Which cytokines regulate the differentiation of Th1 helper cells and are responsible for enhancing cell-mediated immunity?

• A. IL-4 and IL-10

• B. IL-10 and TGF-beta

• C. IL-1 and IL-6

• D. IL-3 and GM-CSF

• E. IL-12 and IFN-gamma

e

Which helper T-cell subset is regulated by IL-17, enhances neutrophil diapedesis, and is implicated in IgE production, asthma, and allergic reactions?

• A. Th1 cells

• B. Th2 cells

• C. Treg cells

• D. Cytotoxic T cells

• E. Th17 cells

e

During a secondary (anamnestic) antibody response, the plateau level of antibody titer typically stabilizes at what fold increase compared to the primary response?

• A. Twofold

• B. Threefold

• C. Fivefold

• D. Eightfold

• E. Tenfold

e

Adipose tissue can act as an endocrine/paracrine source of which cytokine, establishing a potential mechanistic link between obesity and chronic inflammation?

• A. IL-1

• B. TNF-alpha

• C. TGF-beta

• D. IL-10

• E. IL-6