Nokea
A protein-protein interaction domain present both in TLR-4 and MyD88 is:
- A. CARD
- B. TIR
- C. Leucine rich repeat (LRR)
- D. Immunoglobulin-like domain
Correct Answer: B
Rationale: The correct answer is B: TIR. This is because both TLR-4 and MyD88 contain a Toll/interleukin-1 receptor (TIR) domain, which mediates protein-protein interactions in the Toll-like receptor signaling pathway. The other options, such as A (CARD), C (LRR), and D (Immunoglobulin-like domain), are not present in both TLR-4 and MyD88 and do not play a significant role in their interaction in the signaling pathway. This makes B the most appropriate choice as it accurately identifies the common protein-protein interaction domain between TLR-4 and MyD88.
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Macrophages differentiate
- A. From blood neutrophils
- B. In tissues
- C. From the common lymphoid progenitor
- D. In the bone marrow
Correct Answer: B
Rationale: Macrophages differentiate in tissues because they originate from monocytes which leave the bloodstream and mature into macrophages in various tissues. This process is essential for their diverse functions in immune response and tissue maintenance. Choices A, C, and D are incorrect because macrophages do not differentiate from blood neutrophils, the common lymphoid progenitor, or in the bone marrow.
Which condition is associated with increased susceptibility to bacterial infections due to complement deficiencies?
- A. Asthma
- B. Systemic lupus erythematosus (SLE)
- C. Streptococcus pneumoniae infections
- D. Chronic hepatitis
Correct Answer: C
Rationale: The correct answer is C: Streptococcus pneumoniae infections. Complement deficiencies impair the body's ability to fight bacterial infections, particularly encapsulated bacteria like Streptococcus pneumoniae. Asthma (A), SLE (B), and chronic hepatitis (D) are not directly associated with increased susceptibility to bacterial infections due to complement deficiencies. Asthma is a chronic respiratory condition, SLE is an autoimmune disease, and chronic hepatitis affects the liver. Therefore, only Streptococcus pneumoniae infections are directly linked to complement deficiencies.
Which cells play a central role in Type I hypersensitivity reactions?
- A. Neutrophils
- B. Mast cells
- C. Macrophages
- D. Dendritic cells
Correct Answer: B
Rationale: The correct answer is B: Mast cells. Mast cells play a central role in Type I hypersensitivity reactions by releasing histamine, cytokines, and other inflammatory mediators in response to allergens. This triggers the allergic response. Neutrophils (A), Macrophages (C), and Dendritic cells (D) are not central to Type I hypersensitivity reactions. Neutrophils are involved in acute inflammation, macrophages play a role in phagocytosis and antigen presentation, and dendritic cells are important in initiating adaptive immune responses.
Which of the following early contributors to the development of immunology is paired up properly with his or her accomplishment?
- A. Louis Pasteur: demonstrated that cowpox vaccination can protect from smallpox
- B. Paul Ehrlich: identified lymphocytes as the cells mediating adaptive immunity
- C. MacFarlane Burnet: proposed the side-chain theory of antibodies which suggested that multiple antigen receptors are expressed on immune cells
- D. Robert Koch: developed techniques to grow pure bacterial cultures
Correct Answer: D
Rationale: Rationale: Robert Koch is correctly paired with developing techniques to grow pure bacterial cultures. Koch's work laid the foundation for bacteriology and allowed for the isolation and identification of specific disease-causing bacteria. This technique, known as Koch's postulates, revolutionized the field of microbiology by linking specific pathogens to specific diseases.
Summary:
A: Louis Pasteur - Incorrect. While Pasteur is known for his work in vaccination and pasteurization, the provided accomplishment is associated with Edward Jenner, not Pasteur.
B: Paul Ehrlich - Incorrect. Ehrlich is known for his work on immunology and coined the term "magic bullet," but he did not identify lymphocytes as cells mediating adaptive immunity.
C: MacFarlane Burnet - Incorrect. Burnet is known for his clonal selection theory, not the side-chain theory of antibodies as described in the choice.
What type of antibodies predominate in the secondary immune response?
- A. IgM
- B. IgE
- C. IgG
- D. IgD
Correct Answer: C
Rationale: The correct answer is C: IgG. In the secondary immune response, IgG antibodies predominate due to memory B cells rapidly producing them upon re-exposure to the same antigen. IgG provides long-lasting immunity and is more efficient in neutralizing pathogens. IgM (A) is the primary antibody in the initial immune response. IgE (B) is involved in allergic reactions. IgD (D) functions as a receptor on B cells.