The immunoglobulin class which is the least abundant in the normal adult is

Correct Answer: C

Rationale: The correct answer is C, IgE. IgE is the least abundant immunoglobulin in the normal adult because it is primarily involved in allergic responses and parasitic infections, leading to its lower baseline levels compared to other classes. IgG is the most abundant and provides long-term immunity. IgA is found in mucosal areas and secretions, crucial for local immunity. IgD functions primarily as a B cell receptor and its levels are relatively low in circulation. Therefore, IgE stands out as the least abundant in the normal adult due to its specialized role in immune responses.

Correct Answer: C

Rationale: The correct answer is C: "Skip this week and pick up the schedule next week." Bisphosphonates like alendronate should be taken as directed, typically once weekly. It is important to maintain consistency in dosing to maximize effectiveness and minimize potential side effects. Taking a double dose or taking it late can increase the risk of side effects like gastrointestinal irritation or esophageal damage. Skipping a dose and resuming the schedule next week helps maintain the proper dosing interval. Options A and D suggest taking extra doses, which can be harmful. Option B of taking two doses 3 days apart is also incorrect as it deviates from the prescribed weekly schedule.

Correct Answer: A

Rationale: The correct answer is A: Blood. Naïve T cells are circulating in the blood, ready to encounter antigens. They can move to secondary lymphoid organs like lymph nodes. Germinal centers (B) are sites of B cell maturation, not where naïve T cells are primarily found. While some naïve T cells enter lymph nodes (C), they are not mostly located in the medullary region. Naïve T cells can also migrate to non-lymphoid tissues (D), but their primary residence is in the blood.

Correct Answer: D

Rationale: The correct answer is D because dendritic cells do not typically move rapidly through the germinal center during an immune response. Dendritic cells usually interact with T cells in the paracortex to present antigens, and they are not known to migrate rapidly through the germinal center. A: This statement is correct as T cells do make stable and prolonged contacts with APCs in the paracortex during immune responses. B: This statement is incorrect as B cells do not move at the same speed and randomly in follicles in the absence of antigens. They respond to signals and cues in the microenvironment. C: This statement is correct as specific B cells can quickly direct themselves towards the source of antigen during an infection. In summary, choice D is incorrect because dendritic cells do not move rapidly through the germinal center during an immune response, while the other choices accurately describe behaviors of immune cells during immune responses.

Correct Answer: C

Rationale: The correct answer is C because it indicates a specific reason for the intense debate within the scientific community regarding ferrets in Flu research. Mutations in H5N1 creating a strain transmissible among ferrets is significant as it highlights a potential threat of cross-species transmission and the need for further study. A is incorrect as it does not provide a specific reason related to ferrets and their role in Flu research. B is incorrect because it focuses on a specific strain (H1N1) rather than mutations in H5N1. D is incorrect as it mentions publications being put on hold but does not address the core issue of mutations and transmissibility among ferrets.