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Question #45144
The Question
A patient with ADA (Adenosine Deaminase) deficiency undergoes gene therapy where functional ADA cDNA is introduced into their lymphocytes using a retroviral vector. Post-treatment, an ELISA test on the patient's lymphocyte extract yields a strong positive result for the ADA protein. However, the patient still exhibits severe immunodeficiency due to the accumulation of toxic deoxyadenosine. Which of the following is the most scientifically accurate explanation for this discrepancy?
Options
- A.
The retroviral vector failed to integrate the ADA cDNA into the host genome, leading to a complete absence of translation.
- B.
ELISA relies on epitope recognition to confirm the presence of the polypeptide, but cannot verify if the ADA protein is natively folded and enzymatically active.
- C.
The introduced ADA cDNA lacks a promoter region, preventing the transcription of the functional enzyme.
- D.
ELISA detects only the antibodies generated against the viral vector, yielding a false-positive result for the ADA enzyme.
Check Your Answer
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
ELISA|ADA Deficiency Genetic Correction|T-lymphocyte functionality
Why This Question Is Tricky
Common Mistakes
Conceptual Pivot: Students often equate the 'presence of a protein' (detected by structural assays like ELISA) with the 'functional activity' of that protein.
The trap tests the NCERT principle that ELISA is based purely on antigen-antibody interaction, requiring the student to synthesize this with the understanding that a mutated or misfolded protein can still possess recognizable epitopes while lacking enzymatic function.
Quick Facts About This Question
Question Information
| Subject | Biology |
| Chapter | Biotechnology and Its Applications - Class 12 |
| Concept | Molecular Diagnosis by ELISA |
| Difficulty | 8 |
| Cognitive Load | 5 |
| Target Solve Time | 120 sec |
| Access | Free |