AIIMS CRE 2025
Pharmacology
Medium
Which glycoprotein is targeted by entry inhibitors in HIV treatment?
Appeared in: AIIMS CRE 2025
Explanation
- HIV entry into a host cell is a two-step process involving attachment and fusion.
- The glycoprotein gp41 is a transmembrane protein on the HIV envelope responsible for the fusion step.
- After initial attachment via gp120, gp41 undergoes a conformational change that pulls the viral and host cell membranes together, allowing the virus to inject its contents.
- Fusion inhibitors, a specific class of entry inhibitors (e.g., enfuvirtide), work by binding to gp41 and preventing this conformational change, thus blocking viral entry.
Why Other Options Were Wrong
- Option A: gp120 is involved in the initial attachment of HIV to the CD4 receptor, not the fusion of the membranes. While it is a target for a type of entry inhibitor, these are specifically called attachment inhibitors.
- Option C: p24 is an internal core protein (capsid) of the virus. It is not on the viral envelope and does not participate in the entry process.
- Option D: p7 is a nucleocapsid protein that binds to viral RNA. Its role is in the packaging and assembly of new virions inside an already infected cell, not in the initial entry.
Related Visual
Clinical Relevance
- Nursing practice connection: Knowing Pharmacology of antiretroviral drugs, specifically HIV entry inhibitors helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
- Understanding the specific targets of different antiretroviral drugs is crucial for nurses to educate patients about their combination therapy (ART) and the importance of adherence.
- Different drug classes target different stages of the HIV life cycle (e.g., entry, reverse transcription, integration, maturation). Using drugs from multiple classes simultaneously (combination ART) is the standard of care to suppress the virus effectively and prevent drug resistance.
- What if? A patient on enfuvirtide (a gp41 fusion inhibitor) develops severe, painful nodules at their injection sites? The nurse's priority is to assess the sites for infection, ensure the patient is using proper site rotation, and notify the healthcare provider. Persistent severe reactions may require a change in therapy to a different class of antiretroviral.
How to Approach the Question
- First, identify the key terms in the question: 'glycoprotein,' 'entry inhibitors,' and 'HIV.' This directs you to the pharmacology of HIV drugs that block the virus from entering a cell.
- Recall the process of HIV entry. It involves two main glycoproteins on the viral surface: gp120 and gp41.
- Differentiate the roles of these two proteins: gp120 is for 'attachment' to the host cell's CD4 receptor, and gp41 is for 'fusion' of the viral and cell membranes.
- Recognize that 'entry inhibitors' is a broad category that includes both attachment inhibitors and fusion inhibitors.
- Evaluate the options. Both gp120 and gp41 are involved in entry. However, fusion is a distinct, critical step mediated solely by gp41, and 'fusion inhibitors' are a well-known class of drugs targeting it.
- Eliminate the other options. p24 is a capsid protein used for diagnosis, and p7 is a nucleocapsid protein for assembly. Neither is an envelope glycoprotein involved in entry.
Concept Tested & Keywords
- Concept Tested: Pharmacology of antiretroviral drugs, specifically HIV entry inhibitors.
- Stem keywords: glycoprotein, entry inhibitors, HIV treatment
- Lead-in keywords: Which
- Negative lead-in flag: false
Question ID
QkxjBl991gl2W5z4MWlDt1
Reference Book
E6 Pathology-Textbook of PATHOLOGYHarsh Mohan Part 1 (1-214) p. 152-154
E6 Robert Boland, Marcia L. Verduin - Kaplan and Sadock's Comprehensive Text of Psychiatry-Wolters Kluwer Health (2024) (pp 1-16525 of 16525) p. 1942-1944
E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 2094-2096
Practise the full AIIMS CRE 2025
Attempt every question from this paper in a timed mock, then review the full solution for each one.
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