Summer Immuno Lecture 6 Flashcards

A viral infection activates cytotoxic T cells, and a bacterial infection activates helper T cells. Once these T cells begin performing their immune functions, what are they called?
A. Memory cells
B. Anergic cells
C. Effector cells
D. Naive cells

A helper T-cell clone produces IL-4 and IL-5 but not IFN-gamma or IL-17. What best explains this finding?
A. Subset-restricted cytokine programs
B. Uniform cytokine secretion
C. Antibody class deletion
D. TCR chain editing

Effector helper T cells are classically divided into which three major cytokine-producing groups?
A. Treg, Th0, NKT
B. CTL, NK, Th0
C. Th1, Treg, Th2
D. Th1, Th2, Th17

A cell samples microbial products, reads local cytokine signals, and determines how helper T cells should respond. Which cell is being described?
A. Basophil
B. Dendritic cell
C. Eosinophil
D. Plasma cell

A dendritic cell detects both microbial motifs and local soluble immune signals. Which two input systems is it integrating?
A. MHC and TCRs
B. Fc and complement receptors
C. PRRs and cytokine receptors
D. BCRs and integrins

Skin cells near an infection release a characteristic mixture of signals that helps dendritic cells identify the attack location. What are these signals?
A. Cytokines
B. Antibodies
C. Selectins
D. Defensins

An activated dendritic cell instructs a helper T cell how to respond. Which output best conveys this plan?
A. Antibody and complement
B. Histamine and leukotrienes
C. Perforin and granzyme
D. Co-stimulation and cytokines

A dendritic cell leaves infected intestinal tissue and primes a helper T cell. Its instructions mainly reflect what prior information?
A. T-cell receptor affinity
B. Local tissue immune signals
C. Bone marrow stromal signals
D. Plasma antibody concentration

A patient with gram-negative sepsis has macrophage activation after recognition of LPS. Which receptor is most directly involved?
A. TLR4
B. TLR2
C. TLR3
D. TLR9

A dendritic cell detects molecules from gram-positive bacteria. Which Toll-like receptor is classically involved?
A. TLR9
B. TLR3
C. TLR4
D. TLR2

During a viral infection, dendritic cells detect double-stranded RNA produced during replication. Which receptor recognizes it?
A. TLR4
B. TLR3
C. TLR2
D. TLR9

A dendritic cell detects unmethylated CpG DNA during infection. Which receptor is most associated with this pattern?
A. TLR2
B. TLR4
C. TLR9
D. TLR3

Unmethylated CpG dinucleotides are detected by innate immune cells. This pattern most strongly suggests which source?
A. Bacterial DNA
B. Viral envelope
C. Fungal capsule
D. Helminth cuticle

A dendritic cell presents antigen plus IL-12 to a virgin helper T cell. Which helper subset is most likely induced?
A. Th17
B. Th2
C. Th0
D. Th1

Which cytokine trio best matches the classical Th1 profile?
A. IL-4, IL-5, IL-13
B. TNF, IFN-gamma, IL-2
C. IL-17, IL-21, IL-23
D. TGF-beta, IL-6, IL-23

A Th1 response helps activate macrophages and natural killer cells early in infection. Which cytokine performs this function?
A. IL-2
B. IFN-gamma
C. TNF
D. IL-4

A macrophage has already been activated during intracellular infection. Which Th1 cytokine helps keep it activated?
A. IFN-gamma
B. IL-5
C. IL-13
D. IL-21

A patient needs B-cell class switching toward human IgG3 during a Th1 response. Which cytokine provides this influence?
A. IL-23
B. IL-4
C. TNF
D. IFN-gamma

A cytokine keeps NK cells “charged up” and promotes proliferation of CTLs, NK cells, and Th1 cells. Which cytokine is this?
A. IL-17
B. IL-13
C. IL-2
D. IL-10

Tissue invasion by a parasite causes activated dendritic cells to polarize helper T cells toward which cytokine subset?
A. Th17
B. Th2
C. Th1
D. Th0

Which cytokine trio best matches the Th2 subset?
A. IL-4, IL-5, IL-13
B. TNF, IFN-gamma, IL-2
C. IL-17, IL-21, IL-23
D. IL-12, TGF-beta, IL-6

A Th2 cytokine acts as a growth factor for helper T cells already secreting Th2 cytokines. Which cytokine is it?
A. IL-5
B. IL-13
C. IL-21
D. IL-4

A helminth-associated immune response promotes B-cell class switching toward IgE. Which cytokine most directly supports this?
A. IL-2
B. IL-4
C. IL-17
D. IFN-gamma

A mucosal immune response encourages B cells to produce IgA antibodies. Which Th2 cytokine is responsible?
A. IL-13
B. IL-21
C. IL-5
D. TNF

During intestinal parasite defense, goblet-cell mucus production increases. Which cytokine best explains this effect?
A. IL-17
B. IL-23
C. IFN-gamma
D. IL-13

Fungi attack a mucosal barrier. Activated dendritic cells produce TGF-beta plus IL-6. Which helper subset is favored?
A. Th17
B. Th1
C. Th2
D. Th0

Extracellular bacteria attack mucosal tissue. Dendritic cells produce TGF-beta and IL-23. Which helper program is promoted?
A. Th2
B. Th1
C. Th17
D. Treg

Which cytokine set best matches the Th17 subset in this material?
A. IL-4, IL-5, IL-13
B. IL-17, IL-21, IL-23
C. TNF, IFN-gamma, IL-2
D. IL-10, TGF-beta, IL-12

A growth factor expands helper T cells producing the Th17 cytokine subset. Which cytokine is this?
A. IL-23
B. IL-21
C. TNF
D. IFN-gamma

A mucosal fungal infection triggers recruitment of massive numbers of neutrophils. Which cytokine is most responsible?
A. IL-5
B. IL-4
C. IL-21
D. IL-17

B cells guarding mucosal surfaces begin producing IgG3 and IgA. Which Th17 cytokine caused this shift?
A. IL-6
B. IL-12
C. IL-21
D. IL-4

A dendritic cell tells a helper T cell where to migrate but gives no clear effector instructions. What subset results?
A. Th1
B. Th0
C. Th2
D. Th17

A helper T cell retains the ability to produce a broad range of cytokines after incomplete dendritic-cell instruction. What is this called?
A. Th2 polarization
B. Th1 commitment
C. Th17 maturation
D. Th0 subset

A Th0 cell reaches infected tissue and encounters cytokines specific to that site. What happens next?
A. It adopts a relevant subset
B. It becomes permanently anergic
C. It deletes its TCR
D. It stops cytokine secretion

A researcher finds helper T cells that do not fit neatly into Th1, Th2, or Th17 categories. What is the best interpretation?
A. All T cells are mislabeled
B. Only CTLs make cytokines
C. The paradigm has exceptions
D. Dendritic cells lack cytokines

A dendritic cell’s plan for helper T-cell activation is based on co-stimulatory and cytokine signals received from inflamed tissue. What does this emphasize?
A. Random T-cell polarization
B. Context-dependent immune planning
C. Antibody-independent class switching
D. Cytokine-free T-cell activation

A Th1-polarized response becomes dominant during infection. Which cytokine helps suppress proliferation of competing Th2 cells?
A. IL-10
B. IFN-gamma
C. IL-5
D. IL-13

A Th2 response is limiting excessive Th1 expansion. Which cytokine most directly mediates this inhibition?
A. IFN-gamma
B. IL-2
C. IL-17
D. IL-10

A patient mounts a strong Th1 response against an intracellular pathogen. Which competing helper subset is directly suppressed by IFN-gamma?
A. Th2
B. Th17
C. Th0
D. Treg

A patient with helminth infection develops a strong Th2 response. IL-10 from these cells decreases proliferation of which subset?
A. Th0
B. Th17
C. Th1
D. CTL

Why do Th helper subsets inhibit one another?
A. To increase antibody diversity
B. To prevent competing activation
C. To destroy infected cells
D. To increase cytokine range

What is a cytokine property?
A. Limited local range
B. Permanent receptor binding
C. Systemic endocrine spread
D. Antigen-specific recognition

A student assumes cytokines behave mainly like hormones traveling throughout the body. Which correction is best?
A. They mostly enter lymphatics
B. They mostly activate platelets
C. They mostly bind antibodies
D. They mostly act locally

A patient receives intradermal tuberculin and returns days later for evaluation. What immune phenomenon is being tested?
A. Type I hypersensitivity
B. Immune-complex disease
C. Delayed-type hypersensitivity
D. Complement-mediated lysis

The tuberculosis skin test requires waiting several days after tuberculin injection. This delay best reflects which process?
A. T cell-mediated inflammation
B. Immediate mast-cell degranulation
C. IgE-mediated wheal formation
D. Direct bacterial toxin injury

A cytotoxic T lymphocyte kills a virus-infected epithelial cell by delivering enzymes into the target cell. Which pair is most involved?
A. FasL and IL-10
B. Perforin and granzyme B
C. IFN-gamma and IL-4
D. IL-17 and IL-23

A CTL releases a molecule that disrupts the target cell membrane, allowing entry of apoptotic enzymes. Which molecule does this?
A. Granzyme B
B. IFN-gamma
C. IL-10
D. Perforin

A CTL delivers an enzyme into an infected target cell, triggering apoptosis. Which molecule is responsible?
A. Perforin
B. FasL
C. Granzyme B
D. IL-2

A cytotoxic T cell uses a death-receptor pathway instead of granule exocytosis. Which molecule on the CTL is responsible?
A. Fas ligand
B. Granzyme B
C. IFN-gamma
D. IL-17

Fas ligand on a CTL triggers apoptosis by binding which target-cell structure?
A. Class I MHC
B. TLR4
C. CD28
D. Fas receptor

A CTL secretes IFN-gamma near infected cells. What is the main local effect?
A. Decrease class II MHC
B. Increase class I MHC
C. Suppress Fas expression
D. Block granzyme uptake

Why does CTL-derived IFN-gamma help future CTL recognition?
A. It increases IgE switching
B. It recruits eosinophils locally
C. It raises MHC I expression
D. It suppresses viral apoptosis

A virus-infected cell is killed by apoptosis rather than necrosis. Why is apoptosis safer locally?
A. Less surrounding tissue damage
B. More enzyme leakage occurs
C. More complement activation occurs
D. Greater neutrophil rupture occurs

Necrosis of an infected cell can worsen nearby injury because it releases which contents?
A. Antibodies and cytokines
B. MHC and TCRs
C. Enzymes and chemicals
D. Perforin and FasL

A CTL induces apoptosis in a virus-infected cell before viral assembly is complete. What benefit does this provide?
A. Preserves viral RNA
B. Destroys viral nucleic acids
C. Blocks MHC I expression
D. Activates bacterial CpG DNA

Why is apoptosis especially useful in virus-infected cells?
A. It causes tissue swelling
B. It releases lysosomal enzymes
C. It promotes immediate necrosis
D. It destroys viral DNA/RNA

A cytotoxic T cell uses three major weapons against infected host cells. Which set is most complete?
A. IL-4, IL-5, IL-13
B. TLR2, TLR3, TLR9
C. Perforin, FasL, IFN-gamma
D. IgA, IgE, IgG3

A patient has a positive tuberculosis skin test. Which statement best describes the test?
A. Tuberculin causes immediate IgE release
B. Tuberculin triggers delayed hypersensitivity
C. Tuberculin directly lyses macrophages
D. Tuberculin detects serum antibodies