Harr – ISBB UPDATED ACTUAL
Questions and CORRECT Answers
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 Patch
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 differentiate.
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
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. CD 1
B. CD 2
C. CD 3
D. CD 4 or CD 8 - CORRECT ANSWER - C. CD 3
the CD 2 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. CD 1, CD 2, CD 4
B. CD 2, CD 3, CD 8
,C. CD 1, CD 3, CD 4
D. CD 2, CD 3, CD 4 - CORRECT ANSWER - D. Mature. peripheral helper T cells have
the CD 2 (E rosette), CD 3 (mature T cell), and CE 4 (helper) markers.
Which T cell expresses the CD8 marker and acts specifically to kill tumor 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
effective 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 require 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. Pahotaxis - 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.
Questions and CORRECT Answers
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 Patch
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 differentiate.
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
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. CD 1
B. CD 2
C. CD 3
D. CD 4 or CD 8 - CORRECT ANSWER - C. CD 3
the CD 2 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. CD 1, CD 2, CD 4
B. CD 2, CD 3, CD 8
,C. CD 1, CD 3, CD 4
D. CD 2, CD 3, CD 4 - CORRECT ANSWER - D. Mature. peripheral helper T cells have
the CD 2 (E rosette), CD 3 (mature T cell), and CE 4 (helper) markers.
Which T cell expresses the CD8 marker and acts specifically to kill tumor 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
effective 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 require 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. Pahotaxis - 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.
