17 BMD 430 lecture 17 Flashcards

1. Which of the following correctly describes the primary immune response?
A. Rapid response with mainly IgG antibodies
B. Slow response, mainly IgM antibodies first
C. Requires memory cells from a previous exposure
D. Occurs faster due to affinity-matured B cells

2. During the secondary immune response, the predominant antibody type is:
A. IgM
B. IgA
C. IgG
D. IgD

3. Which statement best explains why the secondary immune response is faster?
A. Naïve cells divide faster
B. Memory cells already exist and have higher affinity receptors
C. New somatic mutations occur immediately
D. Antigens are smaller and easier to detect

4. Memory B cells differ from long-lived plasma cells in that memory B cells:
A. Continuously secrete antibodies
B. Are terminally differentiated
C. Circulate and can re-enter germinal centers upon re-exposure
D. Are only found in bone marrow

5. The FcγR2B(1) receptor on B cells functions to:
A. Activate B cells and increase antibody secretion
B. Inhibit B cell activation to prevent overreaction
C. Promote antibody isotype switching
D. Stimulate plasma cell differentiation

6. Hemolytic disease of the newborn occurs when:
A. Rh+ mother has an Rh− baby
B. Rh− mother has an Rh+ baby and develops antibodies against fetal RBCs
C. Rh− mother has an Rh− baby
D. Rh+ father and Rh+ mother produce Rh− baby

7. Rhogam prevents erythroblastosis fetalis by:
A. Stimulating antibody production in the mother
B. Blocking fetal Rh receptors
C. Destroying fetal Rh+ cells before the mother’s immune system can react
D. Neutralizing maternal anti-Rh antibodies

8. Which of the following distinguishes naïve from memory T cells?
A. Naïve T cells express CD45RO
B. Memory T cells express CD45RA
C. Naïve T cells express CD45RA; memory T cells express CD45RO
D. Both express the same CD45 isoform

9. Which memory T cell type primarily remains in tissues such as skin, gut, and lungs?
A. Effector memory (Tem)
B. Central memory (Tcm)
C. Tissue-resident memory (Trm)
D. Naïve T cells

10. Which model of memory cell differentiation is currently considered most accurate?
A. Only effector cells can become memory cells
B. Only early progenitors form memory cells
C. A combination of both early and effector-derived memory cells
D. Memory cells arise from plasma cells only

11. The concept of original antigenic sin explains that:
A. The immune system always produces new antibodies for each new strain
B. The immune system reuses old memory responses even to mutated viruses
C. The immune system forgets previous infections
D. Antibodies mutate faster than viruses

12. Why is influenza a good example of original antigenic sin?
A. It never mutates
B. Its antibodies are very stable
C. It has a high mutation rate, leading to mismatched immune memory
D. It only infects once

13. Cross-reactivity leads to:
A. Immune response against completely unrelated antigens
B. Antibodies recognizing structurally similar antigens
C. No immune response to related pathogens
D. Complete protection from all viruses

14. Cross-protection provides:
A. Temporary protection against related pathogens
B. Immediate full immunity
C. No benefit across infections
D. Autoimmune disease

15. Which statement best describes the key timeline difference between primary and secondary immune responses?

A. Primary is faster and produces IgG; secondary is slower and produces IgM
B. Primary is slow (7–10 days, mainly IgM); secondary is fast (1–3 days, mainly IgG)
C. Both occur at the same speed but differ in antibody type
D. Secondary responses occur only after vaccination

16. How do DNA-level changes differ between primary and secondary immune responses?

A. Secondary responses require new class-switch recombination
B. Primary responses use pre-mutated DNA from memory cells
C. Primary responses perform SHM and class switching for the first time; secondary responses use pre-mutated, high-affinity DNA
D. DNA changes do not differ between the two

17. Which of the following lists the major cell types involved in immunological memory?

A. Mast cells, NK cells, neutrophils
B. Memory B cells, long-lived plasma cells, memory T cells
C. Macrophages, dendritic cells, eosinophils
D. Th17 cells only

18. Which statement correctly compares long-lived plasma cells and memory B cells?

A. Plasma cells circulate; memory B cells stay in bone marrow
B. Plasma cells divide frequently; memory B cells never divide
C. Plasma cells secrete antibodies continuously; memory B cells wait for reactivation
D. Memory B cells secrete antibodies constitutively

19. What is the role of FcγR2B(1) on B cells?

A. Enhances B-cell activation
B. Functions as an inhibitory receptor to prevent overactivation
C. Triggers complement activation
D. Activates macrophages

20. What causes erythroblastosis fetalis (hemolytic disease of the newborn)?

A. ABO incompatibility between mother and fetus
B. Rh− mother makes anti-Rh antibodies that attack a later Rh+ fetus
C. Excess maternal IgA crosses the placenta
D. Fetal T cells attack maternal RBCs

21. How does Rhogam prevent hemolytic disease of the newborn?

A. By blocking maternal IgG from crossing the placenta
B. By suppressing fetal antigen expression
C. By destroying fetal Rh+ RBCs before the mother can recognize them
D. By increasing maternal T-cell tolerance

22. What is the difference between CD45RA and CD45RO?

A. CD45RO is on naïve T cells; CD45RA on memory T cells
B. CD45RA on naïve T cells; CD45RO on memory T cells, allowing faster responses
C. CD45RA is a B-cell marker; CD45RO is a macrophage marker
D. They are identical splice variants

23. Which of the following correctly describes the migration patterns of the three types of memory T cells?

A. Tcm in blood; Tem in lymph nodes; Trm in bone marrow
B. Tcm in tissues; Tem only in lymph nodes; Trm circulate widely
C. Tcm in lymph nodes; Tem circulate in blood and tissues; Trm reside permanently in tissues
D. All memory T cells circulate freely everywhere

24. What is original antigenic sin?

A. When a pathogen mutates to evade T cells
B. When the immune system responds only with innate immunity
C. Preferential use of old antibodies from a prior strain, even if the new strain is different
D. Failure to produce antibodies after vaccination

Why is cross-reactivity important?

A. It causes autoimmunity
B. It allows antibodies to recognize similar pathogens and provide partial protection
C. It prevents memory B-cell formation
D. It blocks antibody production

1. A child receives their second MMR vaccine dose and produces antibodies faster than after the first dose. What explains this?
A. The child’s immune system has more naïve B cells.
B. The second vaccine causes stronger inflammation.
C. Memory B and T cells respond rapidly with high-affinity receptors.
D. The vaccine is more concentrated.

2. A pregnant Rh− woman who never received Rhogam after her first Rh+ pregnancy is now carrying another Rh+ baby. What is likely to occur?
A. The baby will produce anti-Rh antibodies.
B. Maternal memory B cells will attack fetal red blood cells.
C. The baby’s immune system will reject maternal antibodies.
D. The mother will be protected by Rhogam

3. A nurse who had chickenpox as a child is exposed to shingles but does not become ill. What best explains her protection?
A. Naïve B cells immediately produce IgM.
B. Long-lived plasma and memory T cells provide rapid immunity.
C. She has innate resistance to herpesviruses.
D. The exposure dose was too low to infect her.

4. A patient has a genetic defect in the FcγR2B(1) receptor. Which immune issue might they experience?
A. Impaired antibody production
B. Reduced T cell activation
C. Increased risk of autoimmune reactions
D. Weakened complement activation

5. After receiving a flu vaccine, a patient becomes infected with a slightly different strain but has only mild symptoms. Which concepts explain this?
A. Antigenic drift and original antigenic sin
B. Cross-reactivity and cross-protection
C. Autoimmunity and tolerance
D. Antigenic variation and suppression

6. Two mice are studied: one exposed to a virus for the first time, and one exposed twice. Which statement is true?
A. Both mice produce mostly IgM in equal amounts.
B. The first exposure causes a faster response.
C. The second exposure produces mainly IgG antibodies more quickly.
D. The second exposure produces fewer antibodies overall.

7. During a viral infection, a memory T cell in the skin releases cytokines immediately without returning to lymph nodes. What type of memory T cell is this?
A. Central memory (Tcm)
B. Effector memory (Tem)
C. Tissue-resident memory (Trm)
D. Naïve T cell

8. Researchers find that people exposed to an old flu strain respond poorly to a new, mutated strain. What does this illustrate?
A. Cross-protection
B. Original antigenic sin
C. Antigenic drift
D. Clonal deletion

9. Two patients develop memory cells differently: one forms them early, and the other from surviving effector cells. What conclusion is correct?
A. Only early formation is possible.
B. Only effector survival can produce memory.
C. Both models occur, depending on the immune environment.
D. Neither model is accurate.

10. A researcher studies two T cell groups. Group A expresses CD45RA, while Group B expresses CD45RO. Which statement is correct?
A. Group A are memory T cells; Group B are naïve.
B. Group B are memory T cells that respond faster due to altered CD45 signaling.
C. Both groups are naïve but differ in cytokine production.
D. Group A cells are effector memory cells.