HMX Immunology Final UPDATED
ACTUAL Exam Questions and
CORRECT Answers
One of the most important advances in surgery arrived near the end of the nineteenth century.
The British surgeon Joseph Lister hypothesized that using techniques to sterilize surgical
tools and clean the skin at the site of the incision would reduce surgical site infections. Years
later, Dr. Lister wrote this:
"Nothing was formerly more striking in surgical experience than the difference in the
behavior of injuries according to whether the skin was implicated or not. Thus, if the bones of
the leg were broken and the skin remained intact, the surgeon applied the necessary apparatus
without any other anxiety than that of maintaining a good position of the fragments, although
the internal injury to bones and soft parts might be very severe. If, on the other hand, a wound
of the skin was present, communicating with the broken bones, although the damage might be
in other respects comparatively slight, the compound fractu - CORRECT ANSWER-
✔✔Epithelial barriers
Which of the cells below are tissue resident sentinel cells - CORRECT ANSWER- ✔✔mast
cell, macrophage, dendritic cell
Which of the cells below are circulating blood cells that will enter tissue in response to
inflammation? (select two answers) - CORRECT ANSWER- ✔✔Neutrophils
Monoctyes
Mast cell - CORRECT ANSWER- ✔✔Cells that release chemicals (such as histamine) that
promote inflammation.
Neutrophil - CORRECT ANSWER- ✔✔Most abundant leukocyte
Phagocyte that rapidly dies after ingesting microbe
macrophage - CORRECT ANSWER- ✔✔Phagocyte that cleans up apoptotic cells
When a monocyte moves into the tissues, it changes rapidly and becomes a ____________ . -
CORRECT ANSWER- ✔✔macrophage
,Leukocyte adhesion deficiency (LAD) is a genetic defect that leads to recurrent infections in
the tissue and severe problems with wound healing. LAD patients also develop severe
gingivitis (infections and inflammation of the gums). In LAD, leukocyte migration into
tissues is severely impaired. All of these problems can be traced back to a genetic defect. Of
the genetic defects listed below, which is the most likely cause of LAD? - CORRECT
ANSWER- ✔✔A mutation that introduces a stop codon into a gene that encodes part of the
LFA-1 molecule (leading to a truncated protein).
Toll-like receptors for bacterial PAMPs are found on/in the - CORRECT ANSWER- ✔✔cell
membrane
There are a few different proteins that act as inhibitors of NF-kB. There is a very rare genetic
disease in which one of these proteins, IkBα, is mutated. The mutation substantially alters the
stability of the IkBα protein. In patients with this disease, IkBα protein expression does not
change in response to stimuli that cause IkBα degradation in healthy individuals. Consider
the biological role of NF-kB inhibitors. What are the most likely symptoms of this genetic
defect? - CORRECT ANSWER- ✔✔Immunodeficiency with a susceptibility to bacterial
infections.
The complement pathway initiated by host proteins that bind to microbial sugars is called the
____________ pathway. - CORRECT ANSWER- ✔✔lectin pathway
ssRNA (single-stranded RNA) and dsDNA (double-stranded DNA) are present in mammalian
cells. Why don't our plasmacytoid dendritic cells activate an innate immune response against
these self nucleic acids that are necessary for normal cellular function? - CORRECT
ANSWER- ✔✔The TLRs that recognize ssRNA and dsDNA are sequestered in endosomes.
How can the antiviral state be propagated in the absence of immune cells? - CORRECT
ANSWER- ✔✔Type I IFNs are produced by infected epithelial cells; this induces anti-viral
biochemical changes in the same cell and adjacent cells.
A child presents with recurrent bacterial infections. Of the genetic defects described below,
what is the most likely cause of her disease? - CORRECT ANSWER- ✔✔A mutation in the
C3 gene that renders the C3 protein nonfunctional.
, ____________ is the process by which something that is not otherwise recognized as a
pathogen is coated with proteins that make it more recognizable to the immune system. -
CORRECT ANSWER- ✔✔Opsonization
The majority of the symptoms of tetanus infection are caused by the tetanus toxins, chiefly
tetanospasmin. Tetanospasmin is one of the deadliest toxins known; even very small doses
(nanograms) can be lethal. It targets the nerves, causing severe muscle spasms. The tetanus
vaccine consists of inactivated tetanus toxin; the vaccine is highly effective for preventing
tetanus. Inoculation with the tetanus vaccine leads to the production of protective antibodies.
How do these antibodies prevent tetanus? - CORRECT ANSWER- ✔✔Neutralization
Streptococcus pneumoniae is an extracellular bacterium that is a leading cause of bacterial
pneumonia and meningitis, particularly in children and the elderly. Fortunately, most cases of
S. pneumoniae can be prevented with a vaccine that contains components of the bacterial
capsule. The vaccine is known to lead to the production of antibodies that recognize intact
bacteria.
What are the most likely mechanisms activated by these antibodies that result in protection
against S. pneumoniaeinfection? (select two answers) - CORRECT ANSWER- ✔✔The key
is that S. pneumoniae is an extracellular bacterium. The vaccine elicits a humoral immune
response, which generates antibodies that bind to the surface of the bacterium. The antibodies
bound to bacteria can activate complement (direct killing of the bacteria) and opsonization
followed by phagocytosis. ADCC is usually directed against viral proteins displayed on the
surface of cells. It is conceivable that antibodies could neutralize the function of bacterial
components, but direct killing by complement and phagocytosis are the best-characterized
mechanisms for eliminating extracellular bacteria.
There is strong interest in developing a vaccine that would prevent human immunodeficiency
virus (HIV) infection or substantially reduce viral loads in a person with HIV. HIV infects
immune cells by binding to a receptor called CD4 on the surface of those cells. Laboratory
studies have identified rare antibodies that bind to intact HIV viral particles and effectively
control the virus in certain individuals. Structural studies revealed that some of these
antibodies bind to a protein on the surface of HIV at the same location where this protein
binds to CD4.
What is the most likely mechanism of action of these antibodies? - CORRECT ANSWER-
✔✔Neutralization
How many distinct peptide chains are found in a single molecule of IgG? - CORRECT
ANSWER- ✔✔Each IgG antibody is comprised of two heavy chain and two light chain
peptide chains joined by disulfide bridges.
ACTUAL Exam Questions and
CORRECT Answers
One of the most important advances in surgery arrived near the end of the nineteenth century.
The British surgeon Joseph Lister hypothesized that using techniques to sterilize surgical
tools and clean the skin at the site of the incision would reduce surgical site infections. Years
later, Dr. Lister wrote this:
"Nothing was formerly more striking in surgical experience than the difference in the
behavior of injuries according to whether the skin was implicated or not. Thus, if the bones of
the leg were broken and the skin remained intact, the surgeon applied the necessary apparatus
without any other anxiety than that of maintaining a good position of the fragments, although
the internal injury to bones and soft parts might be very severe. If, on the other hand, a wound
of the skin was present, communicating with the broken bones, although the damage might be
in other respects comparatively slight, the compound fractu - CORRECT ANSWER-
✔✔Epithelial barriers
Which of the cells below are tissue resident sentinel cells - CORRECT ANSWER- ✔✔mast
cell, macrophage, dendritic cell
Which of the cells below are circulating blood cells that will enter tissue in response to
inflammation? (select two answers) - CORRECT ANSWER- ✔✔Neutrophils
Monoctyes
Mast cell - CORRECT ANSWER- ✔✔Cells that release chemicals (such as histamine) that
promote inflammation.
Neutrophil - CORRECT ANSWER- ✔✔Most abundant leukocyte
Phagocyte that rapidly dies after ingesting microbe
macrophage - CORRECT ANSWER- ✔✔Phagocyte that cleans up apoptotic cells
When a monocyte moves into the tissues, it changes rapidly and becomes a ____________ . -
CORRECT ANSWER- ✔✔macrophage
,Leukocyte adhesion deficiency (LAD) is a genetic defect that leads to recurrent infections in
the tissue and severe problems with wound healing. LAD patients also develop severe
gingivitis (infections and inflammation of the gums). In LAD, leukocyte migration into
tissues is severely impaired. All of these problems can be traced back to a genetic defect. Of
the genetic defects listed below, which is the most likely cause of LAD? - CORRECT
ANSWER- ✔✔A mutation that introduces a stop codon into a gene that encodes part of the
LFA-1 molecule (leading to a truncated protein).
Toll-like receptors for bacterial PAMPs are found on/in the - CORRECT ANSWER- ✔✔cell
membrane
There are a few different proteins that act as inhibitors of NF-kB. There is a very rare genetic
disease in which one of these proteins, IkBα, is mutated. The mutation substantially alters the
stability of the IkBα protein. In patients with this disease, IkBα protein expression does not
change in response to stimuli that cause IkBα degradation in healthy individuals. Consider
the biological role of NF-kB inhibitors. What are the most likely symptoms of this genetic
defect? - CORRECT ANSWER- ✔✔Immunodeficiency with a susceptibility to bacterial
infections.
The complement pathway initiated by host proteins that bind to microbial sugars is called the
____________ pathway. - CORRECT ANSWER- ✔✔lectin pathway
ssRNA (single-stranded RNA) and dsDNA (double-stranded DNA) are present in mammalian
cells. Why don't our plasmacytoid dendritic cells activate an innate immune response against
these self nucleic acids that are necessary for normal cellular function? - CORRECT
ANSWER- ✔✔The TLRs that recognize ssRNA and dsDNA are sequestered in endosomes.
How can the antiviral state be propagated in the absence of immune cells? - CORRECT
ANSWER- ✔✔Type I IFNs are produced by infected epithelial cells; this induces anti-viral
biochemical changes in the same cell and adjacent cells.
A child presents with recurrent bacterial infections. Of the genetic defects described below,
what is the most likely cause of her disease? - CORRECT ANSWER- ✔✔A mutation in the
C3 gene that renders the C3 protein nonfunctional.
, ____________ is the process by which something that is not otherwise recognized as a
pathogen is coated with proteins that make it more recognizable to the immune system. -
CORRECT ANSWER- ✔✔Opsonization
The majority of the symptoms of tetanus infection are caused by the tetanus toxins, chiefly
tetanospasmin. Tetanospasmin is one of the deadliest toxins known; even very small doses
(nanograms) can be lethal. It targets the nerves, causing severe muscle spasms. The tetanus
vaccine consists of inactivated tetanus toxin; the vaccine is highly effective for preventing
tetanus. Inoculation with the tetanus vaccine leads to the production of protective antibodies.
How do these antibodies prevent tetanus? - CORRECT ANSWER- ✔✔Neutralization
Streptococcus pneumoniae is an extracellular bacterium that is a leading cause of bacterial
pneumonia and meningitis, particularly in children and the elderly. Fortunately, most cases of
S. pneumoniae can be prevented with a vaccine that contains components of the bacterial
capsule. The vaccine is known to lead to the production of antibodies that recognize intact
bacteria.
What are the most likely mechanisms activated by these antibodies that result in protection
against S. pneumoniaeinfection? (select two answers) - CORRECT ANSWER- ✔✔The key
is that S. pneumoniae is an extracellular bacterium. The vaccine elicits a humoral immune
response, which generates antibodies that bind to the surface of the bacterium. The antibodies
bound to bacteria can activate complement (direct killing of the bacteria) and opsonization
followed by phagocytosis. ADCC is usually directed against viral proteins displayed on the
surface of cells. It is conceivable that antibodies could neutralize the function of bacterial
components, but direct killing by complement and phagocytosis are the best-characterized
mechanisms for eliminating extracellular bacteria.
There is strong interest in developing a vaccine that would prevent human immunodeficiency
virus (HIV) infection or substantially reduce viral loads in a person with HIV. HIV infects
immune cells by binding to a receptor called CD4 on the surface of those cells. Laboratory
studies have identified rare antibodies that bind to intact HIV viral particles and effectively
control the virus in certain individuals. Structural studies revealed that some of these
antibodies bind to a protein on the surface of HIV at the same location where this protein
binds to CD4.
What is the most likely mechanism of action of these antibodies? - CORRECT ANSWER-
✔✔Neutralization
How many distinct peptide chains are found in a single molecule of IgG? - CORRECT
ANSWER- ✔✔Each IgG antibody is comprised of two heavy chain and two light chain
peptide chains joined by disulfide bridges.
