front 1 1. Which statement is not one of the tenets of the clonal selection theory? A. Each lymphocyte bears a single type of receptor with unique specificity. B. Binding to antigen activates the lymphocyte. C. All lymphocytes are eliminated after activation. D. Self-reactive lymphocytes are deleted during development. | back 1 C. All lymphocytes are eliminated after activation. |
front 2 2. Stromal cells in the bone marrow support B-cell development through: A. Antibody secretion B. Physical contact and soluble growth factors C. Phagocytosis of immature cells D. Expression of MHC II only | back 2 B. Physical contact and soluble growth factors |
front 3 3. The interaction between SCF on stromal cells and Kit on developing B cells provides: A. Apoptosis signal B. Physical contact survival signal C. Negative selection D. Antigen presentation | back 3 B. Physical contact survival signal |
front 4 4. Which cytokine is secreted by stromal cells to promote B cell development? A. IL-2 B. IL-7 C. TNF-α D. IFN-γ | back 4 B. IL-7 |
front 5 5. The first checkpoint in B cell development tests: A. The light chain rearrangement B. The heavy chain rearrangement C. The ability to bind antigen D. The ability to exit the bone marrow | back 5 B. The heavy chain rearrangement |
front 6 6. The surrogate light chains that test heavy chain structure are: A. λ5 and VpreB B. κ and λ C. β and α D. Igα and Igβ | back 6 A. λ5 and VpreB |
front 7 7. What happens if a heavy chain rearrangement is non-productive on both chromosomes? A. The cell retries until successful B. The cell undergoes apoptosis C. The cell switches to light chain rearrangement D. The cell expresses only IgM | back 7 B. The cell undergoes apoptosis |
front 8 8. How many chances (total) does a light chain have to successfully rearrange? A. 1 B. 2 C. 3 D. 4 | back 8 D. 4 |
front 9 9. Receptor editing occurs only in: A. Heavy chains B. Light chains C. Both heavy and light chains D. T cell receptors | back 9 B. Light chains |
front 10 10. Negative selection of B cells ensures: A. Reactivity to self-antigens B. Death or inactivation of self-reactive B cells C. Expression of both IgM and IgD D. Isotype switching | back 10 B. Death or inactivation of self-reactive B cells |
front 11 11. What happens to a B cell that becomes anergic? A. It proliferates uncontrollably B. It becomes functionally unresponsive C. It dies immediately D. It becomes a plasma cell | back 11 B. It becomes functionally unresponsive |
front 12 12. Where does T cell development begin and end? A. Thymus → Spleen B. Bone marrow → Thymus C. Thymus → Lymph node D. Bone marrow → Lymph node | back 12 B. Bone marrow → Thymus |
front 13 13. The Notch receptor directs a progenitor cell to develop into a: A. B cell B. Macrophage C. T cell D. NK cell | back 13 C. T cell |
front 14 14. Positive selection ensures: A. Self-reactive T cells survive B. T cells recognize self-MHC molecules C. T cells bind antigen with high affinity D. T cells bind to foreign MHC molecules | back 14 B. T cells recognize self-MHC molecules |
front 15 15. Negative selection primarily occurs in the: A. Thymic cortex B. Bone marrow C. Thymic medulla D. Lymph node | back 15 C. Thymic medulla |
front 16 16. The AIRE gene helps promote: A. Cytotoxic T cell activation B. Expression of tissue-specific antigens in the thymus C. Antibody class switching D. B cell proliferation | back 16 B. Expression of tissue-specific antigens in the thymus |
front 17 17. Which best describes “death by neglect”? A. Strong self-MHC binding B. No binding to self-MHC C. Weak binding to self-MHC D. Excessive cytokine exposure | back 17 B. No binding to self-MHC |
front 18 18. Which fate results from TCR binding with intermediate affinity? A. Apoptosis B. Death by neglect C. Treg formation D. Survival | back 18 D. Survival |
front 19 19. ___ Programmed cell death | back 19 Apoptosis |
front 20 20. ___ Functional unresponsiveness | back 20 Anergy |
front 21 21. ___ Process of changing variable regions in light chains | back 21 Receptor Editing |
front 22 22. ___ Occurs during development in bone marrow/thymus | back 22 Central Tolerance |
front 23 23. ___ Occurs after immune cells leave the primary organs | back 23 Peripheral Tolerance |
front 24 24. ___ Antigen binding activates a specific lymphocyte | back 24 Clonal Selection |
front 25 25. ___ Provides survival and growth signals in bone marrow | back 25 Stromal Cell |
front 26 26. Define clonal selection theory and explain why it is important in adaptive immunity. | back 26 Each lymphocyte has a unique receptor; only those binding antigen are selected. Ensures specificity. |
front 27 27. Compare and contrast stem cells and stromal cells. | back 27 Stem: differentiate into many types; Stromal: provide signals/support |
front 28 28. Describe the key events of the Pro-B cell and Pre-B cell stages. | back 28 Pro-B: heavy chain rearrangement (DJ then VDJ). Pre-B: pre-BCR expression, light chain rearrangement. |
front 29 29. What is a Pre-B cell receptor, and why is it important? | back 29 μ heavy chain + surrogate light chains (VpreB & λ5); tests heavy chain function. |
front 30 30. Explain what is meant by a productive vs non-productive rearrangement. | back 30 Productive = functional gene in-frame; Non-productive = out-of-frame, no signal. |
front 31 31. Describe the two checkpoints in B cell development. | back 31 1st = functional heavy chain; 2nd = functional light chain. |
front 32 32. What are the consequences of negative selection of B cells in the bone marrow? | back 32 Removes or inactivates self-reactive B cells → prevents autoimmunity |
front 33 33. Why can receptor editing only occur in light chains and not heavy chains? | back 33 12/23 rule prevents editing in heavy chains. |
front 34 34. Compare central vs. peripheral tolerance in terms of location and function. | back 34 Central = in bone marrow/thymus, early; Peripheral = after circulation, catches escaped self-reactive cells |
front 35 35. What is the purpose of Notch signaling in T cell development? | back 35 Notch drives progenitors toward T cell lineage. |
front 36 36. Outline the general stages of T cell development and where each occurs. | back 36 HSC commitment (BM) → DN1–DN4 (thymus cortex) → positive (cortex) → negative (medulla). |
front 37 37. Define positive selection, negative selection, and the “Goldilocks model” of affinity. | back 37 Positive: binds self-MHC (just right); Negative: too strong = deletion; Goldilocks = moderate survives. |
front 38 38. What is AIRE, and why is it crucial for self-tolerance? | back 38 AIRE = transcription factor exposing tissue antigens in thymus → deletes self-reactive T cells. |