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8.2 Immunological Tolerance β Test 1
Q1. Immunological tolerance is best defined as:β Specific unresponsiveness to a particular antigen (especially self)
Q2. Central tolerance is established in the:β Primary lymphoid organs (thymus and bone marrow)
Q3. Negative selection in the thymus contributes to tolerance by:β Deleting strongly self-reactive T cells
Q4. Peripheral tolerance is needed because:β Some self-reactive lymphocytes escape central tolerance
Q5. Anergy as a tolerance mechanism arises when a lymphocyte:β Recognises antigen without adequate co-stimulation
Q6. Regulatory T (Treg) cells maintain tolerance by:β Actively suppressing other lymphocytes (via IL-10, TGF-Ξ², etc.)
Q7. The transcription factor required for regulatory T-cell development and function is:β FoxP3
Q8. Clonal deletion as a tolerance mechanism refers to:β Apoptosis of self-reactive lymphocytes
Q9. The transcription factor AIRE promotes central tolerance by:β Driving expression of peripheral self-antigens in the thymic medulla
Q10. Factors that favour tolerance rather than immunity to an antigen include:β Very high or very low antigen dose and lack of co-stimulation/danger signals
Q11. Receptor editing contributes to B-cell tolerance by:β Re-rearranging light-chain genes to change a self-reactive receptor
Q12. Failure of self-tolerance leads to:β Autoimmune disease
Q13. Immune privilege (e.g. in the eye and brain) helps maintain tolerance by:β Limiting immune responses at certain sites to protect vital tissue
Q14. Sequestered (hidden) self-antigens can break tolerance if:β Tissue injury exposes them to the immune system
Q15. Oral administration of antigen often induces:β Oral (mucosal) tolerance
Q16. CTLA-4 contributes to peripheral tolerance by:β Delivering inhibitory signals that limit T-cell activation
Q17. Neonatal exposure to an antigen (as in classic experiments) tends to induce:β Tolerance to that antigen
Q18. A key difference between central and peripheral tolerance is that central tolerance:β Acts during lymphocyte development in primary organs
Q19. Tolerance is antigen-specific, which distinguishes it from:β General immunosuppression (which is non-specific)
Q20. Self-reactive antibody levels are low in normal serum largely because:β Self-reactive B cells stimulated without T-cell help undergo functional silencing/apoptosis
Q21. Anergy refers to:β A state of functional unresponsiveness to antigen
Q22. Match each tolerance mechanism with its description and select the correct option.β A-ii, B-iv, C-i, D-iii