AIIMS CRE 2025
Pharmacology
Easy
Which HIV protein is targeted by entry-inhibiting drugs?
Appeared in: AIIMS CRE 2025
Explanation
- The HIV protein gp41 is a transmembrane glycoprotein located on the viral envelope.
- Its primary function is to mediate the fusion of the viral envelope with the host cell's plasma membrane, which is the final step of viral entry.
- Fusion inhibitors, a key class of entry-inhibiting drugs, specifically bind to gp41.
- By binding to gp41, these drugs (like enfuvirtide) prevent the conformational changes necessary for membrane fusion, effectively blocking the virus from entering the host cell.
Why Other Options Were Wrong
- Option A: gp120 is involved in the initial attachment of HIV to the host cell's CD4 receptor, not the fusion step that is the classic target of entry inhibitors like enfuvirtide.
- Option C: p24 is an internal capsid protein that encloses the viral genetic material. It is not located on the viral surface and therefore cannot be a target for drugs that block entry.
- Option D: p17 is the matrix protein, an internal structural component that lines the inner surface of the viral envelope. It is not involved in the entry process.
Related Visual
Clinical Relevance
- Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology of Antiretroviral Drugs as background academic context rather than a clinical decision trigger.
- Entry inhibitors are often reserved for treatment-experienced patients who have developed resistance to other classes of antiretroviral therapy (ART).
- A key nursing role is patient education on the administration of entry inhibitors like enfuvirtide, which is given by subcutaneous injection and can cause significant injection-site reactions.
- What if the patient's virus shows a tropism for CXCR4 instead of CCR5? This is relevant for another type of entry inhibitor, CCR5 antagonists (like maraviroc), which block the host cell co-receptor. If the virus uses CXCR4, maraviroc would be ineffective, but a fusion inhibitor targeting gp41 would still be a potential option as its mechanism is independent of co-receptor type.
How to Approach the Question
- First, identify the core of the question: it asks for the specific HIV protein targeted by 'entry-inhibiting drugs'.
- Recall the structure of the HIV virus, differentiating between external envelope proteins (gp120, gp41) and internal proteins (p24, p17).
- Understand that drugs blocking entry must target surface proteins.
- Differentiate the roles of the two surface proteins: gp120 is for attachment, and gp41 is for fusion.
- Recall the major classes of entry inhibitors. Fusion inhibitors are a classic example that targets a viral protein.
- Connect the fusion inhibitor class to its specific target, gp41, to select the best answer among the choices.
Concept Tested & Keywords
- Concept Tested: Pharmacology of Antiretroviral Drugs
- Stem keywords: HIV protein, entry-inhibiting drugs
- Lead-in keywords: Which
Question ID
QdcBq1FWw_57AEhWKJWnPX
Reference Book
E6 Pathology-Textbook of PATHOLOGYHarsh Mohan Part 1 (1-214) p. 152-154
E6 Nelson Textbook of Pediatrics(2024) — Volume 1 p. 2094-2096
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
Practise the full AIIMS CRE 2025
Attempt every question from this paper in a timed mock, then review the full solution for each one.
More Antimicrobial Drugs Questions
- A nurse is advised to administer inj. Metronidazole to a patient. She knows action of this is:
- Which of the following antitubercular medication has the side effect of Peripheral neuritis?
- A first line medication for pulmonary tuberculosis:-
- Disulfiram is a drug used in treatment of
- Which of the following antitubercular medications has the side effect of Pinkish orange color urine?
- Whole virus inactivated vaccine of COVID-19 is?
- Patients with tuberculosis who are on isoniazid therapy should also be administered?
- Which antibiotic is known as first wonder drug?
- A patient with tuberculosis who is on isoniazid therapy should also be administered?
- Which medication is given to a patient in the pre-operative period to reduce infection?
More AIIMS CRE 2025 Questions
- What is the preferred first-line ART regimen for HIV-infected adults?
- Which action reduces the risk of mother-to-child transmission of HIV during childbirth?
- Which antiretroviral regimen is recommended for newborns exposed to HIV?
- What is the duration of ARV prophylaxis for newborns exposed to HIV?
- What is the recommendation for ARV treatment in HIV-positive pregnant women during labor?
- PEP (Post-exposure prophylaxis) after needle-stick injury should be initiated within:
- How long should post-exposure prophylaxis (PEP) be continued after potential HIV exposure?
- Which body fluid is most likely to transmit HIV through a needle-stick injury?
- Recommended HIV follow-up testing schedule for healthcare workers after needle-stick injury is:
- Which statement about post-exposure prophylaxis is true?