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2.4 Natural Killer (NK) Cells β Test 1
Q1. Natural killer (NK) cells are best classified as cells of the:β Innate immune system (innate lymphoid cells)
Q2. NK cells preferentially kill target cells that have:β Lost or reduced MHC class I ('missing self')
Q3. The activity of an NK cell is determined by a balance between:β Activating and inhibitory receptor signals
Q4. NK cells kill their targets using:β Perforin and granzymes (and FasβFasL)
Q5. NK cells perform antibody-dependent cell-mediated cytotoxicity (ADCC) using the Fc receptor:β CD16 (FcΞ³RIII)
Q6. A cytokine that strongly activates NK cells and enhances their killing is:β IL-12 (and type I interferons)
Q7. NK cells contribute to shaping adaptive immunity by secreting:β IFN-Ξ³, which promotes Th1 responses and activates macrophages
Q8. NK cells are especially important early in infection because they:β Act rapidly without needing prior sensitisation or clonal expansion
Q9. Human NK inhibitory receptors that recognise self MHC class I include:β Killer-cell immunoglobulin-like receptors (KIRs)
Q10. NK cells differ from cytotoxic T cells in that NK cells:β Do not use a rearranged antigen-specific receptor
Q11. The activating NK receptor NKG2D recognises:β Stress-induced ligands on infected or transformed cells
Q12. A cell that downregulates MHC class I to evade cytotoxic T cells becomes vulnerable to:β NK-cell killing
Q13. NK cells are large granular lymphocytes; their granules contain:β Perforin and granzymes
Q14. The common cytokine that supports NK-cell development and survival is:β IL-15
Q15. In ADCC, the antibody isotype that NK cells recognise on coated target cells is:β IgG (via CD16)
Q16. The 'missing self' hypothesis states that NK cells attack cells that:β Fail to display adequate self MHC class I
Q17. NK cells and cytotoxic T cells together provide complementary surveillance because:β CTLs detect MHC-I-presented antigen, while NK cells detect MHC-I loss
Q18. NK cells are important in defence against:β Virus-infected cells and some tumour cells
Q19. A growing area of therapy uses NK cells by:β Engineering or activating NK cells (e.g. CAR-NK) to target tumours
Q20. Match each NK-cell feature with its description and select the correct option.β A-ii, B-i, C-iv, D-iii