HIV affects which of the following most commonly
**Core Concept**
HIV (Human Immunodeficiency Virus) primarily targets and infects a specific subset of immune cells, leading to progressive immunocompromise and increased susceptibility to opportunistic infections.
**Why the Correct Answer is Right**
The virus specifically targets and infects CD4+ T lymphocytes (also known as T-helper cells), which play a crucial role in coordinating the immune response. HIV binds to the CD4 receptor on the surface of these cells, facilitating its entry and subsequent replication. This selective targeting of CD4+ T cells leads to their depletion and disruption of the immune system's ability to respond to pathogens.
**Why Each Wrong Option is Incorrect**
**Option A:** While HIV can infect other immune cells, such as macrophages and dendritic cells, CD4+ T lymphocytes are its primary target.
**Option B:** Neutrophils are not the primary target of HIV infection; they are more involved in acute inflammation and bacterial defense.
**Option C:** B cells, or plasma cells, are not the primary target of HIV infection; they are more involved in antibody production and humoral immunity.
**Clinical Pearl / High-Yield Fact**
HIV infection is characterized by a gradual decline in CD4+ T cell count, often referred to as the "CD4 count," which is a critical prognostic marker for disease progression and treatment response.
**Correct Answer: C. CD4+ T lymphocytes. CD4+ T lymphocytes.**