L-Selectin is

Correct Answer: C

Rationale: The correct answer is C: Expressed on naïve T cells. L-Selectin is a cell adhesion molecule expressed on the surface of naïve T cells. It plays a crucial role in the initial attachment of T cells to high endothelial venules (HEV) in lymphoid tissues, facilitating T cell entry into lymph nodes. It specifically binds to ligands on HEV, allowing T cells to extravasate into lymphoid tissues. Choice A is incorrect because L-Selectin is primarily expressed on naïve T cells rather than effector T cells. Choice B is incorrect as L-Selectin is expressed on HEV, not by them. Choice D is incorrect because L-Selectin is involved in the initial attachment of T cells to endothelial cells, rather than being required for extravasation into tissues.

Correct Answer: D

Rationale: The correct answer is D: Are protease inhibitors. Blocking HIV budding involves inhibiting the action of the viral protease enzyme, which is crucial for processing viral proteins into their functional forms. By targeting protease, the virus cannot mature and infect new cells. RT inhibitors (A) target reverse transcriptase, not budding. Targeting gp120 (B) is focused on viral entry, not budding. Targeting HIV co-receptors (C) is aimed at blocking viral entry, not budding.

Correct Answer: E

Rationale: The correct answer is E, as it states that the question is asking for a statement that is NOT true regarding HPV. Choices A, B, C, and D are all true statements about HPV. A) Both women and men can be infected with HPV. B) HPV can indeed cause cervical cancer. C) The HPV vaccine is a prophylactic recombinant vaccine. D) HPV is a DNA virus that can integrate into the cellular genome. Therefore, the only option left, E, is the correct answer as it contradicts the true statements provided in the other choices.

Correct Answer: D

Rationale: Step 1: Type I hypersensitivity reactions are immediate allergic reactions that occur upon initial exposure to an allergen, not just after a second encounter. Step 2: Food allergies can lead to systemic anaphylaxis due to the rapid release of mediators like histamine. Step 3: TH2 lymphocytes play a crucial role in the development of type I hypersensitivity reactions by promoting IgE production. Step 4: Type I hypersensitivity reactions are not generally classified as genetic disorders since they result from an immune response to allergens, not a single gene defect.

Correct Answer: C

Rationale: The correct answer is C because it states that human strains of Influenza extensively infect epithelial cells throughout the body, which is not true. Influenza primarily infects cells of the respiratory tract, leading to respiratory symptoms. Systemic symptoms such as fever, fatigue, and muscle aches are more related to the body's immune response rather than widespread infection of epithelial cells throughout the body. This statement is incorrect as it misrepresents the pathogenesis of Influenza. Choices A, B, and D are incorrect because they are all true statements supported by scientific evidence regarding Influenza transmission, asymptomatic spread, and viral entry mechanism, respectively.