Nokea
What triggers the activation of lymphocytes in adaptive immunity?
- A. Phagocytosis
- B. Recognition of their specific antigen
- C. Cytokine release by macrophages
- D. Opsonization of pathogens
Correct Answer: B
Rationale: The correct answer is B because lymphocytes are activated in adaptive immunity by recognizing their specific antigen. This recognition is crucial for initiating an immune response tailored to combat a specific pathogen. Phagocytosis (A) is the process of engulfing and destroying pathogens, but it does not directly activate lymphocytes. Cytokine release by macrophages (C) can help in activating other immune cells, but lymphocytes specifically require antigen recognition for activation. Opsonization of pathogens (D) enhances phagocytosis but is not the direct trigger for lymphocyte activation.
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Which of the following is a molecule that inhibits T cell activation, is highly expressed in Tregs and is used in a recombinant (synthetic) form to treat some autoimmune diseases?
- A. CD86
- B. CTLA-4
- C. MHC class II
- D. CD4
Correct Answer: B
Rationale: The correct answer is B: CTLA-4. CTLA-4 inhibits T cell activation by binding to CD80/CD86 on antigen-presenting cells, preventing the co-stimulatory signal required for T cell activation. It is highly expressed in Tregs, which suppress immune responses. Recombinant CTLA-4 (e.g., abatacept) is used to treat autoimmune diseases by blocking T cell activation.
Explanation for other choices:
A: CD86 is a co-stimulatory molecule that activates T cells, not inhibits them.
C: MHC class II molecules present antigens to T cells, they do not inhibit T cell activation.
D: CD4 is a co-receptor that helps T cells recognize antigens presented by MHC class II molecules, it does not inhibit T cell activation.
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.
A patient was given an IM injection of penicillin in the gluteus maximus and developed dyspnea and weakness within minutes following the injection. Which additional assessment findings indicate that the patient is having an anaphylactoid reaction (select all that apply)?
- A. Wheezing
- B. Hypertension
- C. Rash on arms
- D. Feeling of impending doom
Correct Answer: A
Rationale: Anaphylactoid reactions involve symptoms like wheezing, rash, and a sense of impending doom due to severe allergic response.
A patient is scheduled to have a tunneled catheter placed for administration of chemotherapy for breast cancer. When preparing the patient for the catheter insertion, what does the nurse explain about this method of chemotherapy administration?
- A. Decreases the risk for extravasation at the infusion site
- B. Reduces the incidence of systemic side effects of the drug
- C. Does not become occluded as peripherally inserted catheters can
- D. Allows continuous infusion of the drug directly to the area of the tumor
Correct Answer: A
Rationale: Tunneled catheters reduce extravasation risks compared to peripheral lines by delivering medications centrally.
The rearrangement of gene segments that occurs randomly in B cell receptor genes and T cell receptor genes:
- A. Occurs during clonal expansion of B cells and T cells
- B. Involves rapid genetic mutation after lymphocytes become activated
- C. Allows the mature lymphocyte population to recognize an enormous diversity of antigens
- D. Occurs in the DNA of all cells in the body
Correct Answer: C
Rationale: Step 1: Gene rearrangement in B cell and T cell receptor genes creates unique receptor proteins.
Step 2: This diversity allows mature lymphocytes to recognize a wide range of antigens.
Step 3: This process is crucial for adaptive immune response and antigen specificity.
Step 4: Choices A and B do not accurately describe gene rearrangement.
Step 5: Choice D is incorrect as gene rearrangement is specific to lymphocytes, not all cells in the body.