IMM 250 Final Exam Questions with Correct Answers Latest Update 2025-2026
How do barriers defend against infection? - Answers Physically and mechanically keep
pathogens out. Example: stomach and skin. They do not need to go through a process to get
activated; they are immediately active.
Summarize innate immunity? - Answers It involves cells and molecules that get recruited to the
site of infection. Innate cells recognize PAMPs using PRRs. PAMPs are common to a certain
group of pathogens.
Summarize adaptive immunity? - Answers It involves cells and molecules that get recruited to
the site of infection. Lymphocytes are the ones used in the adaptive response. They recognize
antigens by using antigen receptors.
What is an antigen? - Answers A macromolecule that is specific to one pathogen. They are
recognized during the adaptive immune response.
What is an epitope? - Answers A small area of the antigen that is bound by the surface antigen
receptor on the tip of an antibody.
What mechanism do B cells use to recognize a threat? - Answers Epitope binding to antibodies.
What mechanism do T cells use to recognize a threat? - Answers A small protein piece of the
antigen is held up to the T cell receptors. The epitope is presented to the receptor on the T cell
by an MHC molecule.
What is an MHC molecule? - Answers It is a special antigen presenting cell that helps T cells
recognize a threat.
What kinds of threats do B cells assist with? - Answers Extracellular threats. They block entry
into cells and tag pathogens for destruction by secreting antibodies.
What kind of threats do cytotoxic T cells help with? - Answers Intracellular threats. These cells
are useful for when a pathogen gets past the B cell's response. They kill cells that have been
completely infected in order to prevent the spread of a disease.
What kind of help do helper T cells do? - Answers They provide overall help and defence by
secreting cytokines required for the activation of B, Tc, and other innate leukocytes.
How to B cells and T cells have such diverse functionality when humans only have 25,000 genes?
- Answers Gene rearrangement: the B cell receptor and T cell receptor genes consist of many
small segments arranged into one big exon. The small segments can rearrange themselves to
create any possible combinations. This means that there can be a huge variety of proteins that
can be created within a small population of B cells or T cells.
What does the B cell receptor look like? - Answers There are 2 identical antigen binding sites.
,Both of the light chains on the receptor are encoded by the same IgL gene. Both of the heavy
chains are encoded by the same IgH gene.
What does a T cell receptor look like? - Answers It has 1 antigen binding site. It still has 2
different chains: an alpha chain encoded by the TCR alpha gene and a beta chain encoded by
the TCR beta gene.
What are V domains? - Answers These are the top area of the B cell receptor and T cell
receptors. They facilitate recognition of a diverse variety of antigens. They have high structural
variability.
What are C domains? - Answers These are the bottom areas of the B cell receptor and T cell
receptors. They facilitate common functions like signal transduction and clearance.
What are complementarity determining (CDR) regions? - Answers These regions are right at the
tip of the antigen receptors on B cells and T cells. They are hotspots of protein variability.
What is VDJ recombination? - Answers The unique mechanism of genetic recombination that
occurs in B cell and T cell maturation. It results in a high diversity of antibodies and receptors. It
is exclusive to lymphocytes of the adaptive system.
What is the Thyroid? - Answers A gland in the neck that responds to hormones from the pituitary
gland.
What happens if the TSH receptor is blocked by an antibody? - Answers There is decreased
thyroid hormone secretion which leads to fatigue, weight gain, and hair loss. Also known as
hypothyroidism of Hashimomoto's disease.
What happens if an antibody binds to the TSH receptor? - Answers Epithelial cells will mistake
the antibody for TSH and produce overwhelming amounts of the thyroid hormone. This leads to
weight loss, sweating, and rapid heart rate. Also known as hyperthyroidism or Grave's disease.
What are naive lymphocytes? - Answers Lymphocytes that have never encountered an antigen
before.
What is clonal selection? - Answers The process of growth and division of immune cells so that
they can respond to threats better and more specifically.
What are effector cells? - Answers Short lived cells that act quickly to eliminate pathogens.
What are memory cells? - Answers Long lived cells that respond to the same pathogen if
encountered later on in time. This kind of response is why survivors of infection gain immunity
to a disease. It is also why vaccines are effective.
What is Leukemia? - Answers A type of cancer that involves a hematopoietic cell in the bone
marrow becoming malignant. The progeny cells spill out into the blood. It is also known as
, "liquid malignancy."
What is Lymphoma - Answers A type of cancer where a mature B or T cell becomes malignant.
The progeny cells form a solid tumour in the lymphoid tissues (spleen, bone marrow, lymph
nodes).
What is Myeloma? - Answers A type of cancer where a plasma cell becomes malignant and
leads to an endless secretion of antibodies.
What is a plasma cell? - Answers An antibody secreting B cell.
What bacteria is responsible for the triggered immune response in gastric lymphoma? -
Answers Helicobacter pylori
What are lymphoid tissues? - Answers Specialized compartments for lymphocyte maturation
and activation. There are 2 types: primary and secondary.
What are primary lymphoid tissues? - Answers Tissues where lymphocytes mature. Antigen
receptors are first expressed in these tissues.
What are secondary lymphoid tissues? - Answers Tissues where mature naive lymphocytes
meet antigens and get activated. Examples are spleen, lymph nodes, mucosa, and skin
associated tissues.
What is the common lymphoid progenitor? - Answers A cell that is created by the hematopoietic
stem cell. It gives rise to B cell and T cell precursors.
What are mucosal activated lymphoid tissues (MALTs)? - Answers Diffused collections of
lymphocytes that gather together under mucosal surfaces.
Which costimulatory signals do naive T cells need? - Answers Interaction between CD28 on the
T cell and B7 on the antigen providing cell.
Which costimulatory signals do naive B cells need? - Answers Interaction between CD40 on the
B cell and CD40 on the CD4+ helper cell.
Which cytokine is necessary for T cell or B cell differentiation/proliferation? - Answers IL-2
Where can dendritic cells be found? - Answers Everywhere throughout the host tissues
What is lymph? - Answers Fluids that leek out from blood vessels into tissues as blood
circulates throughout the body
What do lymphatic vessels do? - Answers Constantly take up lymph and its continents
(including antigens from tissues) and bring it to the lymph nodes and eventually to the heart.
How are lymph nodes positioned? - Answers Lymph nodes are positioned along the vessels of
How do barriers defend against infection? - Answers Physically and mechanically keep
pathogens out. Example: stomach and skin. They do not need to go through a process to get
activated; they are immediately active.
Summarize innate immunity? - Answers It involves cells and molecules that get recruited to the
site of infection. Innate cells recognize PAMPs using PRRs. PAMPs are common to a certain
group of pathogens.
Summarize adaptive immunity? - Answers It involves cells and molecules that get recruited to
the site of infection. Lymphocytes are the ones used in the adaptive response. They recognize
antigens by using antigen receptors.
What is an antigen? - Answers A macromolecule that is specific to one pathogen. They are
recognized during the adaptive immune response.
What is an epitope? - Answers A small area of the antigen that is bound by the surface antigen
receptor on the tip of an antibody.
What mechanism do B cells use to recognize a threat? - Answers Epitope binding to antibodies.
What mechanism do T cells use to recognize a threat? - Answers A small protein piece of the
antigen is held up to the T cell receptors. The epitope is presented to the receptor on the T cell
by an MHC molecule.
What is an MHC molecule? - Answers It is a special antigen presenting cell that helps T cells
recognize a threat.
What kinds of threats do B cells assist with? - Answers Extracellular threats. They block entry
into cells and tag pathogens for destruction by secreting antibodies.
What kind of threats do cytotoxic T cells help with? - Answers Intracellular threats. These cells
are useful for when a pathogen gets past the B cell's response. They kill cells that have been
completely infected in order to prevent the spread of a disease.
What kind of help do helper T cells do? - Answers They provide overall help and defence by
secreting cytokines required for the activation of B, Tc, and other innate leukocytes.
How to B cells and T cells have such diverse functionality when humans only have 25,000 genes?
- Answers Gene rearrangement: the B cell receptor and T cell receptor genes consist of many
small segments arranged into one big exon. The small segments can rearrange themselves to
create any possible combinations. This means that there can be a huge variety of proteins that
can be created within a small population of B cells or T cells.
What does the B cell receptor look like? - Answers There are 2 identical antigen binding sites.
,Both of the light chains on the receptor are encoded by the same IgL gene. Both of the heavy
chains are encoded by the same IgH gene.
What does a T cell receptor look like? - Answers It has 1 antigen binding site. It still has 2
different chains: an alpha chain encoded by the TCR alpha gene and a beta chain encoded by
the TCR beta gene.
What are V domains? - Answers These are the top area of the B cell receptor and T cell
receptors. They facilitate recognition of a diverse variety of antigens. They have high structural
variability.
What are C domains? - Answers These are the bottom areas of the B cell receptor and T cell
receptors. They facilitate common functions like signal transduction and clearance.
What are complementarity determining (CDR) regions? - Answers These regions are right at the
tip of the antigen receptors on B cells and T cells. They are hotspots of protein variability.
What is VDJ recombination? - Answers The unique mechanism of genetic recombination that
occurs in B cell and T cell maturation. It results in a high diversity of antibodies and receptors. It
is exclusive to lymphocytes of the adaptive system.
What is the Thyroid? - Answers A gland in the neck that responds to hormones from the pituitary
gland.
What happens if the TSH receptor is blocked by an antibody? - Answers There is decreased
thyroid hormone secretion which leads to fatigue, weight gain, and hair loss. Also known as
hypothyroidism of Hashimomoto's disease.
What happens if an antibody binds to the TSH receptor? - Answers Epithelial cells will mistake
the antibody for TSH and produce overwhelming amounts of the thyroid hormone. This leads to
weight loss, sweating, and rapid heart rate. Also known as hyperthyroidism or Grave's disease.
What are naive lymphocytes? - Answers Lymphocytes that have never encountered an antigen
before.
What is clonal selection? - Answers The process of growth and division of immune cells so that
they can respond to threats better and more specifically.
What are effector cells? - Answers Short lived cells that act quickly to eliminate pathogens.
What are memory cells? - Answers Long lived cells that respond to the same pathogen if
encountered later on in time. This kind of response is why survivors of infection gain immunity
to a disease. It is also why vaccines are effective.
What is Leukemia? - Answers A type of cancer that involves a hematopoietic cell in the bone
marrow becoming malignant. The progeny cells spill out into the blood. It is also known as
, "liquid malignancy."
What is Lymphoma - Answers A type of cancer where a mature B or T cell becomes malignant.
The progeny cells form a solid tumour in the lymphoid tissues (spleen, bone marrow, lymph
nodes).
What is Myeloma? - Answers A type of cancer where a plasma cell becomes malignant and
leads to an endless secretion of antibodies.
What is a plasma cell? - Answers An antibody secreting B cell.
What bacteria is responsible for the triggered immune response in gastric lymphoma? -
Answers Helicobacter pylori
What are lymphoid tissues? - Answers Specialized compartments for lymphocyte maturation
and activation. There are 2 types: primary and secondary.
What are primary lymphoid tissues? - Answers Tissues where lymphocytes mature. Antigen
receptors are first expressed in these tissues.
What are secondary lymphoid tissues? - Answers Tissues where mature naive lymphocytes
meet antigens and get activated. Examples are spleen, lymph nodes, mucosa, and skin
associated tissues.
What is the common lymphoid progenitor? - Answers A cell that is created by the hematopoietic
stem cell. It gives rise to B cell and T cell precursors.
What are mucosal activated lymphoid tissues (MALTs)? - Answers Diffused collections of
lymphocytes that gather together under mucosal surfaces.
Which costimulatory signals do naive T cells need? - Answers Interaction between CD28 on the
T cell and B7 on the antigen providing cell.
Which costimulatory signals do naive B cells need? - Answers Interaction between CD40 on the
B cell and CD40 on the CD4+ helper cell.
Which cytokine is necessary for T cell or B cell differentiation/proliferation? - Answers IL-2
Where can dendritic cells be found? - Answers Everywhere throughout the host tissues
What is lymph? - Answers Fluids that leek out from blood vessels into tissues as blood
circulates throughout the body
What do lymphatic vessels do? - Answers Constantly take up lymph and its continents
(including antigens from tissues) and bring it to the lymph nodes and eventually to the heart.
How are lymph nodes positioned? - Answers Lymph nodes are positioned along the vessels of
