Nokea
A TH2 immune response will not induce
- A. Isotype switching to IgE
- B. Secret ion of IL-4
- C. Activation of macrophages
- D. Resistance to Leishmania infection
Correct Answer: E
Rationale: The correct answer is E because a TH2 immune response is associated with isotype switching to IgE and secretion of IL-4, which are essential for allergic responses. Activation of macrophages is not associated with a TH2 response. Resistance to Leishmania infection is mediated by a TH1 response, not TH2.
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What lineage do natural killer (NK) cells belong to?
- A. Myeloid lineage
- B. Erythroid lineage
- C. Lymphoid lineage
- D. Granulocyte lineage
Correct Answer: C
Rationale: The correct answer is C: Lymphoid lineage. NK cells are a type of lymphocyte that is part of the innate immune system. They are derived from common lymphoid progenitors in the bone marrow. NK cells play a crucial role in recognizing and killing infected or abnormal cells. Myeloid lineage (A) gives rise to cells like macrophages and granulocytes, not NK cells. Erythroid lineage (B) produces red blood cells, and granulocyte lineage (D) gives rise to neutrophils, basophils, and eosinophils, not NK cells. Therefore, the correct choice is C as NK cells originate from the lymphoid lineage.
During the course of an immune response to a given antigen, affinity maturation results in survival of:
- A. B cells whose secretion of antibody occurs at a higher rate
- B. B cells whose antibodies bind the antigen more strongly
- C. T cells whose TCRs bind the antigen more strongly
- D. Both B and C are correct
Correct Answer: B
Rationale: Rationale:
1. Affinity maturation is the process where B cells produce antibodies with increased affinity for the antigen over time.
2. B cells whose antibodies bind the antigen more strongly have higher affinity.
3. Survival of B cells with higher affinity antibodies is crucial for effective immune response.
4. A is incorrect as rate of antibody secretion doesn't necessarily correlate with affinity.
5. C is incorrect as T cells are not directly involved in affinity maturation of antibodies.
6. D is incorrect since T cells are not affected by affinity maturation in the context of this question.
The human immunodeficiency virus (HIV)
- A. Is a retrovirus
- B. Is an RNA virus
- C. Is a lentivirus
- D. All of the above A, B and C
Correct Answer: D
Rationale: Step 1: HIV is a retrovirus because it contains RNA as its genetic material and uses the enzyme reverse transcriptase to convert its RNA into DNA.
Step 2: HIV is an RNA virus because its genetic material is RNA.
Step 3: HIV is a lentivirus which is a subgroup of retroviruses known for causing slow-progressing diseases.
Therefore, the correct answer is D as all statements A, B, and C are true based on the characteristics of HIV.
Which of the following is not an outcome of phagocytosis in macrophages
- A. Respiratory burst
- B. Nitric oxide production
- C. Antigen presentation
- D. Complement activation
Correct Answer: D
Rationale: The correct answer is D: Complement activation. Phagocytosis by macrophages involves engulfing and digesting pathogens. Complement activation occurs through a separate pathway involving a series of proteins that enhance the immune response. Phagocytosis does not directly lead to complement activation. Choices A, B, and C are outcomes of phagocytosis in macrophages: Respiratory burst involves production of reactive oxygen species, nitric oxide production helps destroy pathogens, and antigen presentation is important for activating other immune cells.
Which antibody isotype is involved in allergic reactions?
- A. IgG
- B. IgM
- C. IgA
- D. IgE
Correct Answer: D
Rationale: The correct answer is D: IgE. IgE is the antibody isotype involved in allergic reactions. It binds to allergens and triggers the release of histamine and other chemicals, leading to allergic symptoms. IgG (choice A) is involved in long-term immunity, IgM (choice B) is the first antibody produced in response to an infection, and IgA (choice C) is mainly found in mucosal areas and helps prevent pathogens from entering the body. IgE is specifically associated with allergic responses due to its role in triggering the release of inflammatory mediators in response to allergens.