AIDS virus spreads in the body through (MHT-CET)
First, the core concept here is the mechanism of HIV transmission within the host. The question is testing the understanding of the pathophysiology of HIV, specifically the stages of viral entry and replication in the body.
The correct answer is likely related to the process of HIV entering CD4+ T cells. HIV uses the CD4 receptor and a co-receptor, usually CCR5 or CXCR4, to gain entry into the cell. Once inside, it integrates into the host's genome and starts replicating. So the correct answer should mention the use of CD4 and a co-receptor.
Now, looking at the options (even though the options aren't listed here), common distractors might include things like direct cell-to-cell spread without receptors, using other receptors like CD8, or mentioning incorrect pathways. For example, if an option says HIV uses CD8, that's wrong because CD8 is on cytotoxic T cells, not the target for HIV entry. Another wrong option might be that it uses a different receptor like TLRs, which isn't the case. Also, some might confuse the initial entry with the later stages like budding from the cell, which doesn't involve the same receptors.
The clinical pearl here is to remember that HIV entry is dependent on CD4 and CCR5/CXCR4 co-receptors. This is crucial for treatments like CCR5 antagonists (e.g., maraviroc) which block the co-receptor. Also, the initial entry into macrophages and T cells is a key step in the infection process.
So putting it all together, the correct answer should state that HIV spreads by binding to CD4 and a co-receptor, then fusing with the cell membrane. The clinical pearl is about the receptors involved and their role in antiretroviral therapy.
**Core Concept**
HIV (Human Immunodeficiency Virus) spreads in the body by infecting CD4+ T lymphocytes, macrophages, and dendritic cells. The virus binds to the **CD4 receptor** and a **chemokine co-receptor** (typically CCR5 or CXCR4) to gain entry into host cells, initiating viral replication.
**Why the Correct Answer is Right**
HIV enters host cells via receptor-mediated endocytosis. The viral envelope glycoprotein gp120 binds to the CD4 receptor, inducing a conformational change that allows interaction with a co-receptor (CCR5 in macrophages, CXCR4 in T cells). This triggers membrane fusion, releasing the viral RNA into the cell. Integration into the host genome and subsequent replication depend on this initial entry mechanism.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect if it refers to CD8+ T cells—HIV does not use CD8 as a receptor; CD8 is expressed on cytotoxic T cells, which are not primary targets.
**Option B:** Incorrect if it suggests direct cell-to-cell spread without receptor interaction—HIV requires specific receptor binding for entry.
**Option C:** Incorrect if it claims HIV uses TLRs (Toll-like receptors)—these are innate immune sensors, not HIV entry