front 1 1. What interaction marks the initiation of adaptive immunity? A. Cytokine release B. PAMP-PRR interaction C. Three-signal hypothesis D. Complement activation | back 1 C. Three-signal hypothesis |
front 2 2. Which molecules are involved in Signal 1 of T cell activation? A. CD80/CD86 and CD28 B. MHC II/Antigen and TCR C. Cytokine and cytokine receptor D. CD40 and CD40L | back 2 B. MHC II/Antigen and TCR |
front 3 3. What is the purpose of Signal 2? A. Initiates clonal expansion B. Determines T cell fate (activation or anergy) C. Presents antigen to the T cell D. Triggers macrophage activation | back 3 B. Determines T cell fate (activation or anergy) |
front 4 4. Which interaction provides Signal 2? A. MHC I and CD8 B. MHC II and CD4 C. CD80/CD86 (B7) and CD28 D. Cytokine and cytokine receptor | back 4 C. CD80/CD86 (B7) and CD28 |
front 5 5. A T cell receives Signal 1 but no Signal 2. What happens? A. Apoptosis B. Anergy C. Activation D. Proliferation | back 5 B. Anergy |
front 6 6. What molecule determines the type of helper T cell produced? A. The cytokine environment B. MHC expression C. ITAM activation D. CTLA-4 expression | back 6 A. The cytokine environment |
front 7 7. What is the function of pSMAC? A. Signal transduction B. Adhesion C. Cytokine release D. Transcription | back 7 B. Adhesion |
front 8 8. What is the function of CD3? A. Antigen presentation B. Signal transduction for TCR C. Binds MHC molecules D. Acts as a co-stimulatory receptor | back 8 B. Signal transduction for TCR |
front 9 9. Which of the following binds to MHC class I? A. CD4 B. CD8 C. CD28 D. CD40 | back 9 B. CD8 |
front 10 10. Which transcription factors are activated through CD3 signaling? A. FOXP3 ,STAT3 B. NFAT, NF-κB, AP-1 C. IL-2, IL-4 ,IL-10 D. MAPK ,ICAM-1 | back 10 B. NFAT, NF-κB, AP-1 |
front 11 11. What is the function of CTLA-4? A. Co-stimulatory receptor B. Co-inhibitory receptor C. Cytokine receptor D. Adhesion molecule | back 11 B. Co-inhibitory receptor |
front 12 12. Which of the following statements about checkpoint inhibitors is true? A. They block CTLA-4 to keep T cells active B. They activate Tregs C. They prevent cytokine signaling D. They enhance peripheral tolerance | back 12 A. They block CTLA-4 to keep T cells active |
front 13 13. Which cytokine drives autocrine T cell proliferation? A. IL-4 B. IL-2 C. IL-10 D. IFN-γ | back 13 B. IL-2 |
front 14 14. Which helper T cell subtype combats intracellular pathogens? A. TH1 B. TH2 C. TH17 D. Treg | back 14 A. TH1 |
front 15 15. Which helper T cell secretes IL-17 and fights extracellular bacteria/fungi? A. TH1 B. TH2 C. TH17 D. Treg | back 15 C. TH17 |
front 16 16. TH1 | back 16 function: Macrophage activation cytokines: IFN-γ ,TNF role in disease: Tissue inflammation |
front 17 17. TH2 | back 17 function: Allergy cytokines: IL-4, IL-5, IL-13 role in disease: Allergy |
front 18 18. TH17 | back 18 function: Macrophage activation cytokines: IL-17, IL-22 role in disease: Autoimmunity |
front 19 19. Treg | back 19 function: Suppresses other T cells cytokines: IL-10, TGF-β role in disease: Antitumor inhibition |
front 20 20. TFH | back 20 function:Germinal center regulation cytokines: IL-4, IL-21 role in disease: Lymphoid tissue |
front 21 21. Describe the three-signal hypothesis in T cell activation. | back 21 Signal 1 (MHC–TCR), Signal 2 (CD80/86–CD28), Signal 3 (Cytokine–receptor). |
front 22 22. Explain the difference between paracrine and autocrine signaling in Signal 3. | back 22 Paracrine = cytokine acts on nearby cells; Autocrine = IL-2 acts on same T cell to proliferate. |
front 23 23. What is the function of LCK and ITAMs in TCR signaling? | back 23 LCK phosphorylates ITAMs on CD3 → starts TCR signaling cascade. |
front 24 24. List the three outcomes of CD3 signaling. | back 24 Cell survival, proliferation, differentiation. |
front 25 25. What are central and peripheral Tregs, and how do they differ? | back 25 Central Tregs = develop in thymus; Peripheral Tregs = induced in tissues after activation. |
front 26 26. How do Tregs suppress the immune response? | back 26 Use IL-10/TGF-β, IL-2 competition, APC inhibition, or cytotoxicity. |
front 27 27. What is reciprocal inhibition, and why is it important for T cell polarization? | back 27 Opposing pathways inhibit each other; ensures only one helper T subset dominates. |
front 28 28. Describe how a TH1 cell activates macrophages at the site of infection. | back 28 TH1 binds MHC II on macrophage; IFN-γ + CD40L activate macrophage to increase lysosome fusion and NO. |