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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The recirculation of naïve lymphocytes follows which sequential order?
- A. Blood, HEV, LN, efferent lymphatics, thoracic duct, blood
- B. Blood, afferent lymphatics, LN, thoracic duct, blood
- C. Inflammatory sites, afferent lymphatics, LN, efferent lymphatics, thoracic duct, blood
- D. Both A and C are correct
Correct Answer: A
Rationale: The correct answer is A because naïve lymphocytes circulate through blood, enter lymph nodes (LN) via high endothelial venules (HEV), encounter antigens in LN, exit via efferent lymphatics, drain into the thoracic duct, and return to blood circulation. Choice B is incorrect because it skips the step of entering LN through HEV. Choice C is incorrect because it starts with inflammatory sites instead of blood, and it also lacks the step of entering LN through HEV. Choice D is incorrect as only option A correctly follows the sequential order of recirculation of naïve lymphocytes.
Which represents a correct grouping with respect to the target of an immune response, immune response strength, and resulting health status?
- A. Self-antigen, weak response, autoimmune disease
- B. Pathogen, strong response, recurrent infection
- C. Tumour antigen, weak response, cancer
- D. Transplanted organ, strong response, graft acceptance
Correct Answer: C
Rationale: Rationale:
1. Tumor antigens are non-self antigens that trigger a weak immune response due to immune tolerance.
2. Weak immune response against tumor antigens may lead to uncontrolled cell growth, resulting in cancer.
3. Strong immune responses are typically mounted against pathogens to clear infections.
4. Self-antigens should not trigger immune responses to prevent autoimmune diseases.
5. Transplanted organs can elicit strong immune responses leading to rejection, not acceptance.
Summary:
A - Incorrect: Self-antigens should not elicit immune responses to prevent autoimmune diseases.
B - Incorrect: Pathogens typically trigger strong immune responses to clear infections, not recurrent ones.
D - Incorrect: Transplanted organs often lead to strong immune responses and rejection, not acceptance.
What could happen to the woman’s serum osmolality as a result of this meal?
- A. Increased
- B. No change
- C. Decreased
- D. Unchanged
Correct Answer: B
Rationale: The meal contains high amounts of sodium from salt pork and gravy, which would increase serum osmolality due to increased sodium concentration in the blood.
The joints most commonly involved with rheumatoid arthritis include:
- A. Symmetrical involvement of major joints.
- B. Small joints of hands and feet.
- C. Spine,from the sacrum upward to cervical.
- D. Slightly movable joints of the axial skeleton.
Correct Answer: B
Rationale: Rheumatoid arthritis primarily affects small joints symmetrically, especially those in the hands and feet. Major joints and axial skeleton involvement occurs but is less characteristic of early disease presentation.
Alumn is an adjuvant that triggers
- A. TLR4
- B. DAMPs formation
- C. NOD1
- D. TLR9
Correct Answer: B
Rationale: The correct answer is B: DAMPs formation. Alum is known to trigger the release of damage-associated molecular patterns (DAMPs), which are endogenous molecules released by damaged cells. This activation of DAMPs plays a crucial role in initiating and enhancing the immune response. The other choices, TLR4, NOD1, and TLR9, are receptors involved in recognizing specific pathogen-associated molecular patterns (PAMPs) rather than DAMPs. Therefore, they are not directly triggered by alum. This makes choice B the correct answer based on the known mechanism of action of alum as an adjuvant.