EBV receptor mimics ?
**Core Concept**
Epstein-Barr virus (EBV) infects B lymphocytes by binding to its receptor, which mimics the CD21 receptor. This interaction triggers signaling pathways that facilitate viral entry and replication.
**Why the Correct Answer is Right**
The EBV receptor is a viral homologue of the human CD21 receptor, also known as complement receptor 2 (CR2). CD21 is expressed on mature B cells and follicular dendritic cells, and it plays a crucial role in the complement system by binding to C3b. The EBV receptor interacts with CD21 to initiate signaling pathways, including the activation of NF-κB and the phosphorylation of protein tyrosine kinases. This interaction leads to the activation of B cells and the initiation of viral replication.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the EBV receptor. While the EBV receptor is a viral homologue of CD21, it is not a receptor for the complement component C3b.
**Option B:** This option is incorrect because it is not a specific enough description of the EBV receptor. The EBV receptor is a viral protein that interacts with CD21, but it is not simply a receptor for the CD21 protein.
**Option C:** This option is incorrect because it is a completely unrelated receptor. The EBV receptor is not a receptor for the T-cell antigen receptor (TCR).
**Clinical Pearl / High-Yield Fact**
The EBV receptor is an example of a viral homologue, where a viral protein mimics a host receptor to facilitate infection and replication. This is a common mechanism used by viruses to infect host cells, and it highlights the importance of understanding the molecular interactions between viruses and their host cells.
**Correct Answer: D. CD21.