MP NHM CHO-2024 (Shift-1)
Applied Microbiology & Infection control
Easy

The main type of immune cells targeted by HIV is

Appeared in: MP NHM CHO-2024 (Shift-1)

Explanation

  • The Human Immunodeficiency Virus (HIV) has a strong affinity for CD4 receptors, which are most prominently found on the surface of T helper cells.
  • T helper cells (a subset of T cells) are the primary host for HIV replication.
  • The virus enters these cells, replicates, and ultimately destroys them.
  • The progressive depletion of CD4+ T cells is the central feature of HIV disease, leading to severe immunodeficiency.
  • This destruction of T cells cripples the adaptive immune system, making the body vulnerable to opportunistic infections and cancers.

Why Other Options Were Wrong

  • Option A: B cells are responsible for producing antibodies (humoral immunity). They are not the primary cells infected by HIV, although their function is impaired due to the lack of signaling support from T helper cells.
  • Option C: Natural Killer (NK) cells are part of the innate immune system and do not have the CD4 receptor that HIV uses to enter its main target cells.
  • Option D: While macrophages can be infected by HIV (as they also express CD4, but at lower levels) and act as a viral reservoir, the defining characteristic of AIDS is the catastrophic decline in CD4+ T cells, not macrophages.

Related Visual

Visual explanation — Related Visual
  • Visual 1: Diagram - A diagram illustrating the HIV virion with its gp120 surface protein binding to the CD4 receptor and a coreceptor on a T helper lymphocyte, showing the process of viral entry.
  • Visual 2: Graph - A line graph showing the typical course of HIV infection over time, plotting the inverse relationship between viral load (increasing) and CD4+ T cell count (decreasing).
Clinical Relevance
  • Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pathophysiology of HIV and its primary target immune cells as background academic context rather than a clinical decision trigger.
  • Monitoring the CD4+ T cell count is a critical nursing responsibility in managing patients with HIV. It determines the stage of the disease, risk for opportunistic infections, and when to initiate antiretroviral therapy (ART) or prophylactic medications.
  • Patient safety is paramount. A low CD4 count (below 200 cells/mm³) indicates severe immunocompromise (AIDS), requiring the nurse to implement neutropenic precautions and educate the patient on avoiding sources of infection.
  • What if? If a patient's CD4 count drops to 180 cells/mm³, the nursing priority shifts from routine monitoring to active prevention of opportunistic infections like Pneumocystis jirovecii pneumonia (PJP), for which prophylaxis (e.g., with trimethoprim-sulfamethoxazole) is indicated.
How to Approach the Question
  • First, identify the core of the question, which is asking for the 'main' or 'primary' target of a specific pathogen (HIV).
  • Recall knowledge about the pathophysiology of HIV. The name 'Human Immunodeficiency Virus' itself points to its effect on the immune system.
  • Access specific knowledge about virology: HIV is a retrovirus that targets cells with CD4 receptors.
  • Evaluate the options based on this key fact. Which of the listed immune cells is famously known for its CD4 receptor and its role in HIV infection?
  • T cells, specifically T helper cells, are the classic CD4+ cells. This makes them the most likely answer.
  • Eliminate other options: B cells, NK cells, and Macrophages are not the primary target whose destruction defines the progression to AIDS, even if some (like macrophages) can be infected.
Concept Tested & Keywords
  • Concept Tested: Pathophysiology of HIV and its primary target immune cells.
  • Stem keywords: HIV, immune cells, targeted
  • Lead-in keywords: main type
  • Negative lead-in flag: false

Question ID

QJtWuVA9OSXCh8fC8ZWAaT

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