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Question #46490
The Question
Plasmodium species often employ rapid antigenic variation to evade host immunity. In a rare clinical complication of malaria, a patient develops severe autoimmune hemolytic anemia, where the immune system actively destroys uninfected host RBCs. Based on the structural logic of immunological recognition, which of the following is the most scientifically accurate explanation for this phenomenon?
Options
- A.
The constant (Fc) region of the host's antibodies undergoes a mutation, causing it to bind non-specifically to the host's own RBCs.
- B.
Hemozoin released during erythrocytic schizogony acts as a hapten, permanently altering the host's MHC-I molecules to trigger T-cell autoreactivity.
- C.
The variable (Fab) region of antibodies generated against parasite surface antigens exhibits cross-reactivity with structurally similar epitopes on normal host RBCs.
- D.
Sporozoites directly infect memory B-cells instead of hepatocytes, reprogramming them to secrete autoantibodies against the host's systemic organs.
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Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Regulatory_Failure
Understand how NOT, EXCEPT, and logical constraints are used to manipulate exam results.
Concepts Behind This Question
Plasmodium|Antibody Structure Logic|Autoimmunity Principles
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize isolated facts like 'Hemozoin causes malaria symptoms' or 'Sporozoites are the infective stage' without integrating the structural biology of antibodies (Fab vs Fc) with the concept of autoimmunity.
The question tests the ability to link the NCERT concept of 'Autoimmunity' (where the body attacks self-cells due to genetic or unknown reasons, often triggered by cross-reactivity) with the specific structural domains of an antibody (H2L2 model) and the Plasmodium life cycle.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Health and Disease - Class 12 |
| Concept | Life Cycle of Plasmodium |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |