CHS PRACTICE EXAM CERTIFIED
HISTOCOMPATIBILITY SPECIALIST 200
QUESTIONS EXAMINATION TEST 2026
QUESTIONS WITH SOLUTIONS GRADED A+
⩥ Which of the following is not a component of the reticuloendothelial
cell system?
a. Microglial cells
b. Kupffer cells
c. Langerhans cells
d. Neutrophils
e. Monocytes. Answer: d. Neutrophils
⩥ Opsonization is a term to describe what?
a. Lysis of bacteria
b. Coating of bacteria
c. Ingestion of bacteria
d. Killing of bacteria
e. Phagocytosis. Answer: b. Coating of bacteria
,⩥ Which of the following does not describe a role of antibodies in host
defense?
a. They serve as a bridge between bacteria and phagocytes
b. They lyse bacteria
c. They enhance complement binding to the bacterial cell wall
d. They prevent viruses from infecting cells
e. They bind pathogens in mucus secretions. Answer: b. They lyse
bacteria
⩥ MHC Class I and II molecules differ in all of the following except
a. Types of T cells they stimulate
b. Types of cells they are expressed on
c. Which chromosome they are located on
d. Types of antigens they present
e. Whether or not they have foreign peptides in the antigen-binding
groove. Answer: c. Which chromosome they are located on
⩥ The primary role of the proteasome in antigen presentation is to
a. Prevent premature folding of MHC class I molecules
b. Process cytoplasmic proteins
,c. Degrade recycled MHC molecules
d. Bind HLA-DM in the endosome
e. Chaperone peptides to the cell surface. Answer: b. Process
cytoplasmic proteins
⩥ Peptides that bind to MHC class I molecules differ from peptides that
bind to MHC class II molecules in all except which of the following
ways?
a. They are shorter
b. They were processed by different proteases
c. They anchor in the middle instead of the end of the MHC molecule
d. They interact with different subsets of T cells. Answer: c. They anchor
in the middle instead of the end of the MHC molecule
⩥ HLA-DM is primarily involved in the
a. Activation of cytotoxic T cells
b. Loading antigen onto HLA-DR molecules
c. Preventing HLA-A molecules from folding prior to antigen binding
d. Rejection of islet grafts
e. Induction of diabetes mellitus. Answer: b. Loading antigen onto HLA-
DR molecules
, ⩥ The antigen-binding site of an antibody is comprised of which of the
following?
a. The variable region of the light and heavy chains
b. The variable region of the light chain only
c. The entire light chain
d. The entire heavy chain
e. The Fc portion of the immunoglobulin molecule. Answer: a. The
variable region of the light and heavy chains
⩥ The immunoglobulin that binds the most complement is
a. IgA
b. IgD
c. IgM
d. IgG2
e. IgE. Answer: c. IgM
⩥ The immunoglobulin responsible for activating mast cells in an
allergic response is
a. IgA
HISTOCOMPATIBILITY SPECIALIST 200
QUESTIONS EXAMINATION TEST 2026
QUESTIONS WITH SOLUTIONS GRADED A+
⩥ Which of the following is not a component of the reticuloendothelial
cell system?
a. Microglial cells
b. Kupffer cells
c. Langerhans cells
d. Neutrophils
e. Monocytes. Answer: d. Neutrophils
⩥ Opsonization is a term to describe what?
a. Lysis of bacteria
b. Coating of bacteria
c. Ingestion of bacteria
d. Killing of bacteria
e. Phagocytosis. Answer: b. Coating of bacteria
,⩥ Which of the following does not describe a role of antibodies in host
defense?
a. They serve as a bridge between bacteria and phagocytes
b. They lyse bacteria
c. They enhance complement binding to the bacterial cell wall
d. They prevent viruses from infecting cells
e. They bind pathogens in mucus secretions. Answer: b. They lyse
bacteria
⩥ MHC Class I and II molecules differ in all of the following except
a. Types of T cells they stimulate
b. Types of cells they are expressed on
c. Which chromosome they are located on
d. Types of antigens they present
e. Whether or not they have foreign peptides in the antigen-binding
groove. Answer: c. Which chromosome they are located on
⩥ The primary role of the proteasome in antigen presentation is to
a. Prevent premature folding of MHC class I molecules
b. Process cytoplasmic proteins
,c. Degrade recycled MHC molecules
d. Bind HLA-DM in the endosome
e. Chaperone peptides to the cell surface. Answer: b. Process
cytoplasmic proteins
⩥ Peptides that bind to MHC class I molecules differ from peptides that
bind to MHC class II molecules in all except which of the following
ways?
a. They are shorter
b. They were processed by different proteases
c. They anchor in the middle instead of the end of the MHC molecule
d. They interact with different subsets of T cells. Answer: c. They anchor
in the middle instead of the end of the MHC molecule
⩥ HLA-DM is primarily involved in the
a. Activation of cytotoxic T cells
b. Loading antigen onto HLA-DR molecules
c. Preventing HLA-A molecules from folding prior to antigen binding
d. Rejection of islet grafts
e. Induction of diabetes mellitus. Answer: b. Loading antigen onto HLA-
DR molecules
, ⩥ The antigen-binding site of an antibody is comprised of which of the
following?
a. The variable region of the light and heavy chains
b. The variable region of the light chain only
c. The entire light chain
d. The entire heavy chain
e. The Fc portion of the immunoglobulin molecule. Answer: a. The
variable region of the light and heavy chains
⩥ The immunoglobulin that binds the most complement is
a. IgA
b. IgD
c. IgM
d. IgG2
e. IgE. Answer: c. IgM
⩥ The immunoglobulin responsible for activating mast cells in an
allergic response is
a. IgA
