Question

Match the immune tolerance mechanisms in Group I with their respective outcomes in Group II

Group I	Group II
P) Anergy	1) Elimination of activated T-cells after antigen clearance
Q) Activation-induced cell death	2) Inhibition of auto-reactive T-cells at periphery
R) Receptor editing	3) Unresponsiveness to antigens due to lack of co-stimulatory molecules
S) Regulatory T-cells	4) Elimination of auto-reactive B-cells

• A. P-3, Q-1, R-4, S-2
• B. P-4, Q-3, R-1, S-2
• C. P-3, Q-4, R-2, S-1
• D. P-3, Q-2, R-4, S-1

Hint:

Anergy = lack of co-stimulation → functional inactivation.
AICD = apoptosis of activated T-cells → homeostasis.
Receptor editing = B-cell tolerance → prevent autoreactivity.
T-regs = suppression of immune responses in the periphery.

Answer 1

The Correct Option is A

Step 1: Anergy is a state of unresponsiveness of lymphocytes to antigens due to absence of co-stimulatory signals. Hence, P corresponds to (3).
Step 2: Activation-induced cell death (AICD) eliminates activated T-cells after antigen clearance, thus maintaining peripheral tolerance. Hence, Q corresponds to (1).
Step 3: Receptor editing occurs in immature B-cells, allowing rearrangement of light chain genes to eliminate auto-reactive B-cells. Hence, R corresponds to (4).
Step 4: Regulatory T-cells suppress autoreactive T-cells in the periphery by inhibitory cytokines and cell-contact dependent mechanisms. Hence, S corresponds to (2).
Thus, the correct mapping is: P-3, Q-1, R-4, S-2.