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Question #46508
The Question
A patient with Adenosine Deaminase (ADA) deficiency receives an infusion of genetically engineered lymphocytes containing functional ADA cDNA. Despite successfully mounting a primary immune response to a novel pathogen shortly after treatment, the patient fails to mount an effective anamnestic (secondary) response to the same pathogen a few years later without further treatment. Which of the following best explains the fundamental biological limitation of this specific therapeutic approach?
Options
- A.
The retroviral vector used for transfection induces RNA interference, preventing the rapid translation of antibodies during the secondary response.
- B.
The genetically corrected lymphocytes are not immortal; thus, the pool of memory cells required for sustained clonal proliferation eventually depletes.
- C.
The introduced ADA cDNA fails to integrate into the host genome, preventing the initial maturation of T and B lymphocytes in the bone marrow.
- D.
The accumulation of deoxyadenosine in the engineered cells selectively destroys memory B cells while sparing short-lived effector T cells.
Check Your Answer
Correct Answer
Step-by-Step Solution
Explanation
How the Examiner Thinks
Comparative_Analysis
Sharpen your ability to evaluate multiple scenarios and distinguish between competing potential answers.
Concepts Behind This Question
Adenosine Deaminase|T-lymphocyte differentiation|Hematopoietic Stem Cells
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often memorize that gene therapy 'treats' ADA deficiency but fail to integrate the NCERT detail regarding lymphocyte mortality with the immunological concept of memory cells.
The trap lies in assuming that a successful primary response guarantees a secondary response, overlooking that somatic gene therapy does not confer immortality to the engineered cells, thereby preventing long-term immunological memory unless stem cells are targeted.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Human Health and Disease - Class 12 |
| Concept | Primary vs Secondary Immune Response |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |