Immunology & Serology Exam (Questions)
*From the following, identify a specific component of the adaptive immune system that
is formed in response to antigenic stimulation:
A. Lysozyme
B. Complement
C. Commensal organisms
D. Immunoglobulin - correct Answer-*D. Immunoglobulin is a specific part of the
adaptive immune system and is formed only in response to a specific antigenic
stimulation. Complement, lysozyme, and commensal organisms all act nonspecifically
as a part of the adaptive immune system. These three components do not require any
type of specific antigenic stimulation.
*Which two organs are considered the primary lymphoid organs in which
immunocompetent cells originate and mature?
A. Thyroid and Peyer's patches B. Thymus and bone marrow
C. Spleen and mucosal-associated lymphoid tissue (MALT)
D. Lymph nodes and thoracic duct - correct Answer-*B. The bone marrow and thymus
are considered primary lymphoid organs because immunocompetent cells either
originate or mature in them. Some immunocompetent cells mature or reside in the bone
marrow (the source of all hematopoietic cells) until transported to the thymus, spleen, or
Peyer's patches, where they process antigen or manufacture antibody. T lymphocytes,
after originating in the bone marrow, travel to the thymus to mature and di fferentiate.
*What type of B cells are formed after antigen stimulation?
A. Plasma cells and memory B cells
B. Mature B cells
C. Antigen-dependent B cells
*A Mature B cells exhibit surface immunoglobulin that may cross link a foreign antigen,
thus forming the activated B cell and leading to capping and internalization of antigen.
The activated B cell gives rise to plasma cells that produce and secrete
immunoglobulins and memory cells that reside in lymphoid organs.D. Receptor-
activated B cells - correct Answer-*A. Mature B cells exhibit surface immunoglobulin
that may cross link a foreign antigen, thus forming the activated B cell and leading to
capping and internalization of antigen. The activated B cell gives rise to plasma cells
that produce and secrete immunoglobulins and memory cells that reside in lymphoid
organs.
*T cells travel from the bone marrow to the thymus for maturation. What is the correct
order of the maturation sequence for T cells in the thymus?
A. Bone marrow to the cortex; after thymic education, released back to peripheral
circulation
,B. Maturation and selection occur in the cortex; migration to the medulla; release of
mature T cells to secondary lymphoid organs
C. Storage in either the cortex or medulla; release of T cells into the peripheral
circulation
D. Activation and selection occur in the medulla; mature T cells are stored in the cortex
until activated by antigen - correct Answer-*B. Immature T cells travel from the bone
marrow to the thymus to mature into functional T cells. Once in the thymus, T cells
undergo a selection and maturation sequence that begins in the cortex and moves to
the medulla of the thymus. Thymic factors such as thymosin and thymopoietin and cells
within the thymus such as macrophages and dendritic cells assist in this sequence.
After completion of the maturation cycle, T cells are released to secondary lymphoid
organs to await antigen recognition and activation.
*Which cluster of differentiation (CD) marker appears during the first stage of T-cell
development and remains present as an identifying marker for T cells?
A. CD1
B. CD2
C. CD3
D. CD4 or CD8 - correct Answer-*B. The CD2 marker appears during the first stage of
T-cell development and can be used to differentiate T cells from other lymphocytes.
This T-lymphocyte receptor binds sheep red blood cells (RBCs). This peculiar
characteristic was the basis for the classic E rosette test once used to enumerate T
cells in peripheral blood. CD2 is not specific for T cells, however, and is also found on
large granular lymphocytes (LGL or natural killer [NK] cells).
*Which markers are found on mature, peripheral helper T cells? A. CD1, CD2, CD4
B. CD2, CD3, CD8
C. CD1, CD3, CD4
D. CD2, CD3, CD4 - correct Answer-*D. Mature, peripheral helper T cells have the CD2
(E rosette), CD3 (mature T cell), and CD4 (helper) markers.
*Which T cell expresses the CD8 marker and acts specifically to kill tumors or virally
infected cells?
A. Helper T
B. T suppressor
C. T cytotoxic
D. T inducer/suppressor - correct Answer-*C. T cytotoxic cells recognize antigen in
association with major histocompatibility complex (MHC) class I complexes and act
against target cells that express foreign antigens. These include viral antigens and the
human leukocyte antigens (HLA) that are the target of graft rejection
*How are cytotoxic T cells (TC cells) and natural killer (NK) cells similar?
A. Require antibody to be present B. Effective against virally infected cells
C. Recognize antigen in association with HLA class II markers
D. Do not bind to infected cells - correct Answer-*B. Both TC and NK cells are e ffective
against virally infected cells, and neither requires antibody to be present to bind to
,infected cells. NK cells do not exhibit MHC class restriction, whereas activation of TC
cells requires the presence of MHC class I molecules in association with the viral
antigen.
*What is the name of the process by which phagocytic cells are attracted to a substance
such as a bacterial peptide?
A. Diapedesis
B. Degranulation
C. Chemotaxis
D. Phagotaxis - correct Answer-*C. Chemotaxis is the process by which phagocytic
cells are attracted toward an area where they detect a disturbance in the normal
functions of body tissues. Products from bacteria and viruses, complement components,
coagulation proteins, and cytokines from other immune cells may all act as chemotactic
factors.
*All of the following are immunologic functions of complement except:
A. Induction of an antiviral state B. Opsonization
C. Chemotaxis
D. Anaphylatoxin formation - correct Answer-*A. Complement components are serum
proteins that function in opsonization, chemotaxis, and anaphylatoxin formation but do
not induce an antiviral state in target cells. This function is performed by interferons
*Which complement component is found in both the classic and alternative pathways?
A. C1
B. C4
C. Factor D
D. C3 - correct Answer-*D. C3 is found in both the classic and alternative (alternate)
pathways of the complement system. In the classic pathway, C3b forms a complex on
the cell with C4b2a that enzymatically cleaves C5. In the alternative pathway, C3b binds
to an activator on the cell surface. It forms a complex with factor B called C3bBb which,
like C4b2a3b, can split C5.
*Which immunoglobulin(s) help(s) initiate the classic complement pathway?
A. IgA and IgD
B. IgM only
C. IgG and IgM
D. IgG only - correct Answer-*C. Both IgG and IgM are the immunoglobulins that help to
initiate the activation of the classic complement pathway. IgM is a more potent
complement activator, however.
*How is complement activity destroyed in vitro?
A. Heating serum at 56°C for 30 min
B. Keeping serum at room temperature of 22°C for 1 hour
C. Heating serum at 37°C for 45 min
D. Freezing serum at 0°C for 24 hours - correct Answer-*A. Complement activity in
serum in vitro is destroyed by heating the serum at 56°C for 30 min. In test procedures
, where complement may interfere with the test system, it may be necessary to destroy
complement activity in the test sample by heat inactivation.
*What is the purpose of C3a, C4a, and C5a, the split products of the complement
cascade?
A. To bind with specific membrane receptors of lymphocytes and cause release of
cytotoxic substances
B. To cause increased vascular permeability, contraction of smooth muscle, and release
of histamine from basophils
C. To bind with membrane receptors of macrophages to facilitate phagocytosis and the
removal of debris and foreign substances
D. To regulate and degrade membrane cofactor protein after activation by C3
convertase - correct Answer-*B. C3a, C4a, and C5a are split products of the
complement cascade that participate in various biological functions such as vasodilation
and smooth muscle contraction. These small peptides act as anaphylatoxins, e.g.,
effector molecules that participate in the inflammatory response to assist in the
destruction and clearance of foreign antigens
*Which region of the immunoglobulin molecule can bind antigen?
A. Fab
B. Fc
C. CL
D. CH - correct Answer-*A. The Fab (fragment antigen binding) is the region of the
immunoglobulin molecule that can bind antigen. Two Fab fragments are formed from
hydrolysis of the immunoglobulin molecule by papain. Each consists of a light chain and
the VH and CH1 regions of the heavy chain. The variable regions of the light and heavy
chains interact, forming a specific antigen-combining site.
*Which region determines whether an immunoglobulin molecule can fix complement?
A. VH
B. CH
C. VL
D. CL - correct Answer-*B. The composition and structure of the constant region of the
heavy chain determine whether that immunoglobulin will fix complement. The Fc
fragment (fragment crystallizable) is formed by partial immunoglobulin digestion with
papain and includes the CH2 and CH3 domains of both heavy chains. The complement
component C1q molecule will bind to the CH2 region of an IgG or IgM molecule.
*Which immunoglobulin class(es) has (have) a J chain?
A. IgM
B. IgE and IgD
C. IgM and sIgA
D. IgG3 and IgA - correct Answer-*C. Both IgM and secretory IgA have a J chain joining
individual molecules together; the J chain in IgM joins five molecules and the J chain in
sIgA joins two molecules.
*From the following, identify a specific component of the adaptive immune system that
is formed in response to antigenic stimulation:
A. Lysozyme
B. Complement
C. Commensal organisms
D. Immunoglobulin - correct Answer-*D. Immunoglobulin is a specific part of the
adaptive immune system and is formed only in response to a specific antigenic
stimulation. Complement, lysozyme, and commensal organisms all act nonspecifically
as a part of the adaptive immune system. These three components do not require any
type of specific antigenic stimulation.
*Which two organs are considered the primary lymphoid organs in which
immunocompetent cells originate and mature?
A. Thyroid and Peyer's patches B. Thymus and bone marrow
C. Spleen and mucosal-associated lymphoid tissue (MALT)
D. Lymph nodes and thoracic duct - correct Answer-*B. The bone marrow and thymus
are considered primary lymphoid organs because immunocompetent cells either
originate or mature in them. Some immunocompetent cells mature or reside in the bone
marrow (the source of all hematopoietic cells) until transported to the thymus, spleen, or
Peyer's patches, where they process antigen or manufacture antibody. T lymphocytes,
after originating in the bone marrow, travel to the thymus to mature and di fferentiate.
*What type of B cells are formed after antigen stimulation?
A. Plasma cells and memory B cells
B. Mature B cells
C. Antigen-dependent B cells
*A Mature B cells exhibit surface immunoglobulin that may cross link a foreign antigen,
thus forming the activated B cell and leading to capping and internalization of antigen.
The activated B cell gives rise to plasma cells that produce and secrete
immunoglobulins and memory cells that reside in lymphoid organs.D. Receptor-
activated B cells - correct Answer-*A. Mature B cells exhibit surface immunoglobulin
that may cross link a foreign antigen, thus forming the activated B cell and leading to
capping and internalization of antigen. The activated B cell gives rise to plasma cells
that produce and secrete immunoglobulins and memory cells that reside in lymphoid
organs.
*T cells travel from the bone marrow to the thymus for maturation. What is the correct
order of the maturation sequence for T cells in the thymus?
A. Bone marrow to the cortex; after thymic education, released back to peripheral
circulation
,B. Maturation and selection occur in the cortex; migration to the medulla; release of
mature T cells to secondary lymphoid organs
C. Storage in either the cortex or medulla; release of T cells into the peripheral
circulation
D. Activation and selection occur in the medulla; mature T cells are stored in the cortex
until activated by antigen - correct Answer-*B. Immature T cells travel from the bone
marrow to the thymus to mature into functional T cells. Once in the thymus, T cells
undergo a selection and maturation sequence that begins in the cortex and moves to
the medulla of the thymus. Thymic factors such as thymosin and thymopoietin and cells
within the thymus such as macrophages and dendritic cells assist in this sequence.
After completion of the maturation cycle, T cells are released to secondary lymphoid
organs to await antigen recognition and activation.
*Which cluster of differentiation (CD) marker appears during the first stage of T-cell
development and remains present as an identifying marker for T cells?
A. CD1
B. CD2
C. CD3
D. CD4 or CD8 - correct Answer-*B. The CD2 marker appears during the first stage of
T-cell development and can be used to differentiate T cells from other lymphocytes.
This T-lymphocyte receptor binds sheep red blood cells (RBCs). This peculiar
characteristic was the basis for the classic E rosette test once used to enumerate T
cells in peripheral blood. CD2 is not specific for T cells, however, and is also found on
large granular lymphocytes (LGL or natural killer [NK] cells).
*Which markers are found on mature, peripheral helper T cells? A. CD1, CD2, CD4
B. CD2, CD3, CD8
C. CD1, CD3, CD4
D. CD2, CD3, CD4 - correct Answer-*D. Mature, peripheral helper T cells have the CD2
(E rosette), CD3 (mature T cell), and CD4 (helper) markers.
*Which T cell expresses the CD8 marker and acts specifically to kill tumors or virally
infected cells?
A. Helper T
B. T suppressor
C. T cytotoxic
D. T inducer/suppressor - correct Answer-*C. T cytotoxic cells recognize antigen in
association with major histocompatibility complex (MHC) class I complexes and act
against target cells that express foreign antigens. These include viral antigens and the
human leukocyte antigens (HLA) that are the target of graft rejection
*How are cytotoxic T cells (TC cells) and natural killer (NK) cells similar?
A. Require antibody to be present B. Effective against virally infected cells
C. Recognize antigen in association with HLA class II markers
D. Do not bind to infected cells - correct Answer-*B. Both TC and NK cells are e ffective
against virally infected cells, and neither requires antibody to be present to bind to
,infected cells. NK cells do not exhibit MHC class restriction, whereas activation of TC
cells requires the presence of MHC class I molecules in association with the viral
antigen.
*What is the name of the process by which phagocytic cells are attracted to a substance
such as a bacterial peptide?
A. Diapedesis
B. Degranulation
C. Chemotaxis
D. Phagotaxis - correct Answer-*C. Chemotaxis is the process by which phagocytic
cells are attracted toward an area where they detect a disturbance in the normal
functions of body tissues. Products from bacteria and viruses, complement components,
coagulation proteins, and cytokines from other immune cells may all act as chemotactic
factors.
*All of the following are immunologic functions of complement except:
A. Induction of an antiviral state B. Opsonization
C. Chemotaxis
D. Anaphylatoxin formation - correct Answer-*A. Complement components are serum
proteins that function in opsonization, chemotaxis, and anaphylatoxin formation but do
not induce an antiviral state in target cells. This function is performed by interferons
*Which complement component is found in both the classic and alternative pathways?
A. C1
B. C4
C. Factor D
D. C3 - correct Answer-*D. C3 is found in both the classic and alternative (alternate)
pathways of the complement system. In the classic pathway, C3b forms a complex on
the cell with C4b2a that enzymatically cleaves C5. In the alternative pathway, C3b binds
to an activator on the cell surface. It forms a complex with factor B called C3bBb which,
like C4b2a3b, can split C5.
*Which immunoglobulin(s) help(s) initiate the classic complement pathway?
A. IgA and IgD
B. IgM only
C. IgG and IgM
D. IgG only - correct Answer-*C. Both IgG and IgM are the immunoglobulins that help to
initiate the activation of the classic complement pathway. IgM is a more potent
complement activator, however.
*How is complement activity destroyed in vitro?
A. Heating serum at 56°C for 30 min
B. Keeping serum at room temperature of 22°C for 1 hour
C. Heating serum at 37°C for 45 min
D. Freezing serum at 0°C for 24 hours - correct Answer-*A. Complement activity in
serum in vitro is destroyed by heating the serum at 56°C for 30 min. In test procedures
, where complement may interfere with the test system, it may be necessary to destroy
complement activity in the test sample by heat inactivation.
*What is the purpose of C3a, C4a, and C5a, the split products of the complement
cascade?
A. To bind with specific membrane receptors of lymphocytes and cause release of
cytotoxic substances
B. To cause increased vascular permeability, contraction of smooth muscle, and release
of histamine from basophils
C. To bind with membrane receptors of macrophages to facilitate phagocytosis and the
removal of debris and foreign substances
D. To regulate and degrade membrane cofactor protein after activation by C3
convertase - correct Answer-*B. C3a, C4a, and C5a are split products of the
complement cascade that participate in various biological functions such as vasodilation
and smooth muscle contraction. These small peptides act as anaphylatoxins, e.g.,
effector molecules that participate in the inflammatory response to assist in the
destruction and clearance of foreign antigens
*Which region of the immunoglobulin molecule can bind antigen?
A. Fab
B. Fc
C. CL
D. CH - correct Answer-*A. The Fab (fragment antigen binding) is the region of the
immunoglobulin molecule that can bind antigen. Two Fab fragments are formed from
hydrolysis of the immunoglobulin molecule by papain. Each consists of a light chain and
the VH and CH1 regions of the heavy chain. The variable regions of the light and heavy
chains interact, forming a specific antigen-combining site.
*Which region determines whether an immunoglobulin molecule can fix complement?
A. VH
B. CH
C. VL
D. CL - correct Answer-*B. The composition and structure of the constant region of the
heavy chain determine whether that immunoglobulin will fix complement. The Fc
fragment (fragment crystallizable) is formed by partial immunoglobulin digestion with
papain and includes the CH2 and CH3 domains of both heavy chains. The complement
component C1q molecule will bind to the CH2 region of an IgG or IgM molecule.
*Which immunoglobulin class(es) has (have) a J chain?
A. IgM
B. IgE and IgD
C. IgM and sIgA
D. IgG3 and IgA - correct Answer-*C. Both IgM and secretory IgA have a J chain joining
individual molecules together; the J chain in IgM joins five molecules and the J chain in
sIgA joins two molecules.
