Epstein Barr virus causes autoimmunity by -(
Epstein-Barr virus (EBV) is known to be associated with several autoimmune diseases. The main mechanism I remember is molecular mimicry. That's where the virus's antigens resemble human antigens, leading the immune system to attack self-tissues. So, the correct answer should be related to molecular mimicry.
Wait, the options aren't given, but common distractors might include other mechanisms like immune complex deposition, cytokine storm, or B cell activation. Let me break it down.
Molecular mimicry is when the virus has proteins similar to the host's. The immune response against the virus's proteins then cross-reacts with the host's tissues. For example, in multiple sclerosis or systemic lupus erythematosus, EBV has been implicated this way. So that's the core concept.
The other options: immune complex deposition is more common in diseases like SLE, but that's a different mechanism. Cytokine storm is a hyperinflammatory response, not directly related to autoimmunity. B cell activation is part of EBV's life cycle but not the cause of autoimmunity. So each incorrect option can be explained as not directly causing autoimmunity.
Clinical pearl: EBV's role in autoimmunity is a high-yield fact for exams. Remember that molecular mimicry is the key mechanism here. Make sure to highlight that in the explanation.
**Core Concept** Epstein-Barr virus (EBV) contributes to autoimmunity primarily through **molecular mimicry**, where viral antigens resemble host proteins, leading to cross-reactive immune responses against self-tissues. This mechanism is implicated in conditions like systemic lupus erythematosus (SLE) and multiple sclerosis (MS).
**Why the Correct Answer is Right** EBV encodes proteins with structural homology to human proteins, such as **Ro/SSA** and **La/SSB**, which are autoantigens in SLE. The immune system, trained to attack EBV-infected cells, mistakenly targets these self-antigens, initiating autoimmune reactions. This cross-reactivity is a classic example of molecular mimicry, a key pathogenic mechanism in infectious trigger-induced autoimmunity.
**Why Each Wrong Option is Incorrect**
**Option A:** *Immune complex deposition* is a mechanism in post-streptococcal glomerulonephritis, not EBV-driven autoimmunity.
**Option B:** *Cytokine storm* refers to excessive inflammation in sepsis or cytokine release syndrome, unrelated to EBV-induced autoimmunity.
**Option C:** *B cell hyperactivation* is a hallmark of EBV infection (e.g., in infectious mononucleosis) but does not directly cause autoimmunity.
**Clinical Pearl / High-Yield Fact** EBV is a well-established environmental trigger for autoimmune diseases like SLE and MS. Remember: **molecular mimicry** is the exam-favorite mechanism linking viral infections to autoimmunity. Mnemonic: *Viral "mimic" = autoimmune "strike".*
**Correct Answer: C. Molecular mimicry**