Which of the following is NOT true about multiple sclerosis (MS)

Correct Answer: A

Rationale: The correct answer is A: Sex bias observed with males more at risk of developing the disease. This statement is NOT true because MS actually has a sex bias towards females, with women being more at risk. This is due to hormonal, genetic, and immunological factors. The other choices are true: B is correct as MS is more common in northern regions, possibly due to environmental factors; C is correct since MS is characterized by demyelination of neurons leading to various symptoms; and D is correct as experimental autoimmune encephalomyelitis (EAE) is an animal model often used to study MS, induced by injecting myelin components to trigger an immune response.

Correct Answer: B

Rationale: The correct answer is B because upregulation of endothelial adhesion molecules is the first event during an acute inflammatory response. This event facilitates the initial recruitment of leukocytes, including neutrophils, to the site of inflammation. Extravasation of neutrophils (choice A) occurs after adhesion molecules are upregulated. Secretion of opsonins (choice C) and phagocytosis (choice D) occur later in the inflammatory response process after the neutrophils have been recruited to the site of inflammation.

Correct Answer: D

Rationale: The correct answer is D: Increased migration of dendritic cells from tissues to lymph nodes. Complement activation does not directly lead to the migration of dendritic cells. Complement activation can lead to increased recruitment of inflammatory cells (A), opsonization of pathogens (B), and lysis of pathogens (C). Dendritic cells typically migrate to lymph nodes to present antigens to T cells, but this process is not directly mediated by complement activation.

Correct Answer: D

Rationale: Step 1: Adjuvants like AS03 induce danger signals by activating innate immunity, enhancing the response to the vaccine. Step 2: Adjuvants generally boost the innate immune response by increasing antigen presentation and cytokine production. Step 3: Adjuvants create a slower release of antigen, forming an antigen depot which prolongs immune stimulation. Summary: Choice D is correct because adjuvants like AS03 do induce danger signals, boost the innate immune response, and create a slower release of antigen, leading to enhanced vaccine efficacy. Choices A, B, and C are incorrect as they do not encompass all the effects of adjuvants in flu vaccines.

Correct Answer: C

Rationale: The correct answer is C because immunoglobulin gene rearrangement creates a complete V exon in the B cell DNA. This process happens during B cell development, where segments of V, D, and J gene regions are rearranged to form a functional immunoglobulin gene. This rearrangement occurs before transcription, so option A is incorrect. Option B is incorrect because the V exon is not complete in the germline DNA, but rather created through rearrangement in the B cell DNA. Option D is incorrect as it combines two incorrect statements.