The innate immune system’s “memory” is best described as hard-wired defense against which invaders?
A. Specific prior attackers
B. Common invaders
C. Self-antigens
D. Tumor neoantigens

B. Common invaders

A macrophage responds more vigorously to a second microbial challenge after a prior exposure. What is this called?
A. Central memory
B. Trained immunity
C. Somatic hypermutation
D. Peripheral tolerance

B. Trained immunity

Trained immunity usually has which duration and distribution?
A. Lifelong and systemic
B. Weeks-months and local
C. Days and systemic
D. Years and lymphoid

B. Weeks-months and local

The innate immune system uses hard-wired receptors to recognize what?
A. Broad pathogen classes
B. Specific lifetime attackers
C. Somatically mutated epitopes
D. Cognate peptide-MHC only

A. Broad pathogen classes

Adaptive immune memory is best distinguished by remembering what?
A. Broad microbial patterns
B. Common tissue stress
C. Specific encountered attackers
D. Local cytokine gradients

C. Specific encountered attackers

During an initial B-cell response, which set of B-cell products is generated?
A. CTLs, Tfh, iTregs
B. Th1, Th2, Th17
C. FDCs, TDCs, mTECs
D. Short plasma, long plasma, central memory

D. Short plasma, long plasma, central memory

Short-lived plasma B cells are produced in which structure?
A. Lymphoid follicles
B. Thymic cortex
C. Splenic red pulp
D. Bone marrow niche

A. Lymphoid follicles

After generation, short-lived plasma B cells travel mainly to which sites?
A. Thymus and MALT
B. Bone marrow and spleen
C. Cortex and paracortex
D. PALS and thymus

B. Bone marrow and spleen

Short-lived plasma B cells mainly perform which function?
A. Edit light chains
B. Present self-antigens
C. Produce abundant antibodies
D. License NK cells

C. Produce abundant antibodies

Both types of memory B cells require assistance from which cells?
A. NK cells
B. T cells
C. Neutrophils
D. Eosinophils

B. T cells

Long-lived plasma cells take up residence mainly where?
A. Bone marrow
B. Thymic medulla
C. Peyer patches
D. Inflamed mucosa

A. Bone marrow

Long-lived plasma cells provide lifelong immunity by doing what?
A. Continual modest antibody production
B. Constant massive cytokine release
C. Permanent TCR rearrangement
D. Rapid neutrophil recruitment

A. Continual modest antibody production

Central memory B cells reside mainly in which location?
A. Peripheral tissues
B. Primary lymphoid organs
C. Secondary lymphoid organs
D. Bloodstream only

C. Secondary lymphoid organs

Central memory B cells are best described as memory “stem cells” because they do what?
A. Maintain and replace memory pools
B. Kill infected epithelial cells
C. Present self-antigen in thymus
D. Downregulate Class I MHC

A. Maintain and replace memory pools

During a repeat infection, central memory B cells can rapidly generate which cells?
A. Short-lived plasma B cells
B. Medullary thymic epithelial cells
C. Follicular dendritic cells
D. Natural regulatory T cells

A. Short-lived plasma B cells

Memory T cells are generated only when T-cell activation depends on help from which cell type?
A. NK cells
B. Th cells
C. Plasma cells
D. Neutrophils

B. Th cells

After naive T cells activate, proliferate, and receive tissue-travel passports, they are called what?
A. Central T cells
B. Effector T cells
C. Anergic T cells
D. Virgin T cells

B. Effector T cells

After an infection resolves, approximately what fraction of effector T cells die?
A. 10%
B. 30%
C. 60%
D. 90%

D. 90%

Some surviving effector T cells remain near the original tissue encounter site. What are they called?
A. Central memory T cells
B. Effector memory T cells
C. Tissue-resident memory T cells
D. Follicular helper T cells

C. Tissue-resident memory T cells

Some surviving effector T cells patrol through blood and lymph. What are they called?
A. Effector memory T cells
B. Tissue-resident memory T cells
C. Central memory T cells
D. Inducible regulatory T cells

A. Effector memory T cells

Some memory T cells remain in secondary lymphoid organs. What are they called?
A. Tissue-resident memory T cells
B. Effector memory T cells
C. Central memory T cells
D. Natural regulatory T cells

C. Central memory T cells

Which helper T-cell subsets are described as having long memories?
A. Th1, Th2, Th17
B. iTreg, nTreg, Tfh
C. CTL, NK, Tfh
D. Th0, CTL, iTreg

A. Th1, Th2, Th17

Which T-cell subset has short memory because it turns immune responses off?
A. Th1 cells
B. Th17 cells
C. Th2 cells
D. iTreg cells

D. iTreg cells

Why is it useful for iTregs to have short memories?
A. Prevents prolonged immune suppression
B. Increases antibody affinity
C. Promotes NK licensing
D. Maintains thymic selection

A. Prevents prolonged immune suppression

A vaccine induces bone marrow plasma cells that survive for years and secrete low-level antibody. Which cells are responsible?
A. Short-lived plasma cells
B. Long-lived plasma cells
C. Central memory B cells
D. Marginal-zone B cells

B. Long-lived plasma cells

A patient has rapid antibody expansion after re-exposure because memory “stem cells” generate new plasma cells. Which cells mediate this?
A. Central memory B cells
B. Long-lived plasma cells
C. Tissue-resident memory T cells
D. Effector memory T cells

A. Central memory B cells

A skin infection leaves T cells stationed locally after resolution. Which memory compartment is being formed?
A. Central memory
B. Effector memory
C. Tissue-resident memory
D. Natural regulatory

C. Tissue-resident memory

A previously infected patient has T cells circulating through blood and lymph, ready for reactivation. Which compartment is this?
A. Effector memory
B. Central memory
C. Tissue-resident memory
D. Short-lived plasma

A. Effector memory

A memory T cell remains in a lymph node rather than patrolling peripheral tissues. Which compartment is this?
A. Tissue-resident memory
B. Effector memory
C. Central memory
D. Trained immunity

C. Central memory

A defect prevents T-cell help during B-cell activation. Which outcome is most directly impaired?
A. Memory B-cell generation
B. NK missing-self recognition
C. Innate trained immunity
D. Short cytokine half-life

A. Memory B-cell generation

A patient previously infected with a virus is re-exposed years later and clears it faster. One major reason memory cells respond better is that they are now what?
A. More numerous on duty
B. Less antigen-specific
C. Newly generated in thymus
D. Unable to undergo apoptosis

A. More numerous on duty

Compared with a first immune response, a second immune response is faster partly because memory B and T cells are what?
A. Harder to stimulate
B. Easier to activate
C. Unable to migrate
D. Independent of antigen

B. Easier to activate

A memory B cell responds to antigen with a higher-affinity receptor than its original naive precursor. Which process explains this upgrade?
A. Receptor editing
B. Positive selection
C. Somatic hypermutation
D. Missing-self recognition

C. Somatic hypermutation

A memory B cell produces a different antibody isotype than its original naive version. Which process caused this change?
A. Class switching
B. AICD
C. NK licensing
D. Central tolerance

A. Class switching

Which feature is shared by memory B-cell and memory T-cell systems?
A. Long-lived plasma cells
B. Somatic hypermutation
C. Central memory cells
D. Secreted antibody deployment

C. Central memory cells

Which memory cell type can fine-tune antigen receptors after activation?
A. T cells only
B. B cells only
C. NK cells only
D. Both B and T cells

B. B cells only

Why can memory B cells improve receptor affinity over time while memory T cells cannot?
A. B cells undergo somatic hypermutation
B. T cells lack antigen receptors
C. T cells cannot become memory
D. B cells avoid class switching

A. B cells undergo somatic hypermutation

Which statement best describes T-cell memory compared with B-cell memory?
A. T cells form plasma equivalents
B. T cells lack central memory
C. T cells lack long-lived plasma analog
D. T cells constantly secrete antibodies

C. T cells lack long-lived plasma analog

After an infection resolves, which immune product can continue to be deployed because of B-cell memory?
A. Antibodies
B. TCRs
C. Fas ligand
D. Class I MHC

A. Antibodies

Which cell type produces antibodies that may persist after an invasion is over?
A. T cells
B. B cells
C. NK cells
D. Dendritic cells

B. B cells

A repeat infection is controlled rapidly because many antigen-specific lymphocytes already exist and require less stimulation. Which cells best explain this?
A. Naive lymphocytes
B. Memory lymphocytes
C. Thymic epithelial cells
D. Follicular dendritic cells

B. Memory lymphocytes

Which pair best describes memory B-cell upgrades?
A. Class switching, somatic hypermutation
B. Anergy, receptor deletion
C. Positive selection, AIRE expression
D. Missing self, NK licensing

A. Class switching, somatic hypermutation