Which type of cells are the primary target for HIV infection?

AIIMS CRE 2025

Applied Microbiology & Infection control

Easy

Appeared in: AIIMS CRE 2025

Explanation

The Human Immunodeficiency Virus (HIV) primarily targets CD4+ T lymphocytes, also known as T-helper cells.
HIV's surface glycoprotein (gp120) binds to the CD4 receptor on these T-cells, which is the crucial first step for viral entry and infection.
The virus replicates within and ultimately destroys these cells, leading to a progressive decline in their numbers.
This depletion of CD4+ T cells is the central cause of the immunodeficiency seen in AIDS, as these cells are vital for coordinating the body's immune response.

Option A: B lymphocytes are responsible for producing antibodies. While their function is severely impaired in advanced HIV due to the lack of help from CD4 T cells, they are not the primary cell type that HIV infects.
Option C: Natural killer (NK) cells are part of the innate immune system and help destroy infected cells. They are not the primary target for HIV infection.
Option D: Platelets are small, anucleated cell fragments involved in blood clotting. They do not have CD4 receptors and are not a target for HIV infection.

Visual 1: Diagram - A diagram illustrating the HIV life cycle, showing the virus binding to the CD4 receptor on a T-helper lymphocyte, entering the cell, and using reverse transcriptase to replicate.
Visual 2: Graph - A line graph showing the typical progression of HIV infection over time, plotting the inverse relationship between viral load (increasing) and CD4 cell count (decreasing) in an untreated individual.

Clinical Relevance

Nursing practice connection: Knowing Primary cellular target of HIV infection helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
Monitoring the CD4 T lymphocyte count is a cornerstone of managing patients with HIV. It determines the stage of the disease, the risk of opportunistic infections, and the need to start or change antiretroviral therapy (ART).
A CD4 count below 200 cells/mm³ is a defining criterion for an AIDS diagnosis, signaling severe immunodeficiency and prompting the initiation of prophylaxis against opportunistic infections like Pneumocystis jirovecii pneumonia (PJP).
The goal of ART is to suppress HIV replication to undetectable levels, which allows the CD4 cell count to recover, thereby restoring immune function and preventing disease progression.

How to Approach the Question

First, identify the core of the question: it asks for the primary cellular target of HIV.
Recall the pathophysiology of HIV. The virus is known for causing immunodeficiency.
Consider the options in the context of the immune system. B lymphocytes, CD4 T lymphocytes, and Natural killer cells are all immune cells. Platelets are involved in clotting.
Focus on the specific mechanism of HIV entry. The virus's name itself (Human Immunodeficiency Virus) points to its effect on the immune system. The key is to remember which specific immune cell it targets for entry.
Remember that HIV binds to the CD4 receptor. Therefore, the primary target must be cells that express this receptor, which are the CD4 T lymphocytes (T-helper cells).
Eliminate the other options based on their primary functions: B cells make antibodies, NK cells are for innate killing, and platelets are for clotting. None of these are the main entry point for HIV.

Concept Tested & Keywords

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