Which of the following concerned with Leishmania is NOT true

Correct Answer: a

Rationale: The correct answer is A: Mediated by IgE. Leishmania infection is not primarily mediated by IgE antibodies. The immune response against Leishmania involves T cells, macrophages, and cytokines. IgE is not a major player in the defense against Leishmania. Choices B, C, and D are incorrect because Leishmania is indeed a unicellular parasite, activation of macrophages is essential for killing the parasite, and Leishmania can hide inside neutrophils to escape the host immune attack.

Correct Answer: A

Rationale: The correct answer is A. Integration is a stage of HIV life cycle that involves the insertion of viral DNA into the host cell's genome, facilitated by the enzyme integrase. To explain why A is incorrect, integrase is a viral enzyme, not a host enzyme. B is correct as some anti-HIV drugs target the integration stage to prevent viral replication. C is correct as integrated proviral DNA allows for duplication during cell division. D is correct as integration requires the formation of double-stranded viral DNA.

Correct Answer: C

Rationale: The correct answer is C: Natural killer cells. Natural killer cells are part of the innate immune system and play a crucial role in identifying and destroying infected or abnormal cells. They are able to recognize and target cells that lack specific markers, providing a rapid response to infections. Explanation for incorrect choices: A: B lymphocytes are part of the adaptive immune system, not innate immunity. B: T lymphocytes are also part of the adaptive immune system, not involved in innate immunity. D: Plasma cells are differentiated B cells that produce antibodies in the adaptive immune response, not part of innate immunity.

Correct Answer: C

Rationale: The correct answer is C: IFN-alpha. This is because IFN-alpha belongs to the interferon family, not the interleukin family. Interleukins are a subset of cytokines that are primarily involved in regulating immune responses, while interferons have antiviral properties. IL-1, IL-22, and IL-10 are all interleukins and are part of the interleukin family. Therefore, IFN-alpha is the only cytokine listed that is not included in the interleukin family.

Correct Answer: B

Rationale: The correct answer is B: Fighting cancer by targeting abnormal cells. The immune system plays a crucial role in cancer by identifying and eliminating abnormal cells that can develop into tumors. This process is known as immunosurveillance. Through mechanisms like T cells and natural killer cells, the immune system can detect and destroy cancerous cells before they can grow and spread. This function is essential in preventing the development and progression of cancer. Choices A, C, and D are incorrect: A: Promoting cell growth - The immune system does not promote cell growth in cancer; rather, it regulates and suppresses the growth of abnormal cells. C: Enhancing pathogen resistance - While the immune system does enhance resistance against pathogens, this is not its critical function in cancer. D: Stimulating autoimmune responses - Autoimmune responses involve the immune system attacking healthy cells, not targeting cancerous cells.