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9.5 Regulation of the Immune Response β Test 1
Q1. A key cell type that actively suppresses immune responses to maintain balance is the:β Regulatory T (Treg) cell
Q2. The cytokine IL-10 regulates immunity mainly by:β Suppressing inflammation and dampening macrophage/Th1 activity
Q3. Th1 and Th2 responses regulate each other by:β Cross-inhibition: IFN-Ξ³ suppresses Th2 and IL-4 suppresses Th1
Q4. Negative feedback by antibody helps regulate responses because high antibody levels:β Can inhibit further B-cell activation (e.g. via FcΞ³RIIB)
Q5. Inhibitory checkpoint receptors such as CTLA-4 and PD-1 regulate T cells by:β Delivering inhibitory signals that limit activation
Q6. Activation-induced cell death (AICD) regulates lymphocyte numbers by:β Triggering apoptosis of repeatedly/strongly activated T cells (via FasβFasL)
Q7. The contraction phase after an immune response serves to:β Remove most effector cells and restore homeostasis
Q8. Neuroendocrine regulation of immunity includes the effect of:β Glucocorticoids (cortisol) suppressing immune responses
Q9. The idiotype network theory (Jerne) proposes that immune responses are regulated by:β Interactions between antibodies and anti-idiotype antibodies
Q10. Oral tolerance is an example of regulation in which:β Antigen given orally induces systemic unresponsiveness to it
Q11. A regulatory role of complement-regulatory proteins (e.g. factor H, DAF, CD59) is to:β Protect host cells from complement-mediated damage
Q12. TGF-Ξ² contributes to immune regulation by:β Suppressing immune responses and promoting Treg/IgA development
Q13. Failure of immune regulation can result in:β Autoimmunity, chronic inflammation or allergy
Q14. Cytokine antagonists that regulate inflammation include:β IL-1 receptor antagonist (IL-1Ra)
Q15. Antigen clearance regulates responses because, once antigen is removed:β The stimulus for activation declines and the response winds down
Q16. Regulatory T cells suppress other cells by mechanisms including:β Secreting IL-10/TGF-Ξ², consuming IL-2 and CTLA-4-mediated inhibition
Q17. Glucocorticoids are widely used to control inflammation because they:β Broadly suppress cytokine production and immune-cell function
Q18. An advantage of having multiple regulatory mechanisms is that they:β Balance effective defence against the risk of immunopathology
Q19. PD-1 engagement is especially relevant in chronic infection/cancer because persistent antigen can cause:β T-cell exhaustion with reduced effector function
Q20. The immune network theory (idiotype network) was proposed by:β Niels Jerne
Q21. Idiotypic determinants of an antibody are located in the:β Variable region
Q22. Match each regulatory mechanism with its description and select the correct option.β A-iii, B-ii, C-i, D-iv