The precursor of IL-1β is processed to its active form by

Correct Answer: B

Rationale: The correct answer is B: Caspase 1. Caspase 1 is responsible for the cleavage of pro-IL-1β into its active form IL-1β. This process involves the activation of Caspase 1 by various inflammasomes upon sensing danger signals. Pro-caspase 1 (Choice A) is the inactive precursor form of Caspase 1 and is not involved in processing IL-1β. Procaspase 8 (Choice C) and Caspase 8 (Choice D) are part of the extrinsic apoptosis pathway and are not directly involved in the processing of IL-1β. Therefore, the correct choice is Caspase 1 as it specifically cleaves pro-IL-1β to its active form.

Correct Answer: D

Rationale: The correct answer is D because somatic hypermutation can lead to the formation of antibodies with higher affinity for the antigen by introducing point mutations in the variable regions of immunoglobulin genes. This process mainly occurs in the complementarity-determining regions (CDRs) of immunoglobulin heavy and light chain genes, which are critical for antigen binding. Somatic hypermutation takes place in the germinal centers of secondary lymphoid organs, where B cells undergo rapid proliferation and selection based on antigen binding affinity. Therefore, all the statements in choices A, B, and C are correct, making option D the right answer.

Correct Answer: B

Rationale: The correct answer is B: Linear. T cells recognize linear epitopes, which are sequences of amino acids displayed in a linear fashion on the antigen's surface. This recognition occurs through the T cell receptor binding to the linear epitope. Conformational epitopes (A) involve multiple amino acid residues brought together in a specific three-dimensional structure. Epitopes on the antigen surface (C) are correct, but not all T cell epitopes are necessarily on the surface. Epitopes buried inside the antigen (D) are not accessible to T cell receptors for recognition. Thus, the correct choice is B due to the linear presentation of epitopes for T cell recognition.

Correct Answer: B

Rationale: The correct answer is B because there are no reports of the Black Death dating back to 1000 B.C. The Black Death specifically refers to the pandemic outbreak of the bubonic plague in the 14th century. The first recorded pandemic of the Black Death occurred in the 14th century, not in 1000 B.C. The other choices are incorrect because A is true as the Black Death did devastate Europe in the 14th century, C is true as plague is still present in some countries, and D is true as plague can be treated with antibiotics if caught early.

Correct Answer: D

Rationale: The correct answer is D: Peptidoglycan. Peptidoglycan is a structural component of bacterial cell walls and does not directly contribute to the pathogenicity or virulence of the bacterium. Flagella aid in motility and colonization, effector proteins manipulate host cells, and toxins damage host tissues, all of which are virulence factors. Peptidoglycan is essential for maintaining cell shape and integrity but does not directly enhance the ability of the bacteria to cause disease.