Nokea
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.
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A hybridoma:
- A. Secretes both polyclonal and monoclonal antibodies
- B. Is generated from the fusion of two antigen-activated B cells
- C. Can live in tissue culture indefinitely
- D. All of these options describe a hybridoma
Correct Answer: C
Rationale: Step-by-step rationale:
1. Hybridoma is a cell line formed by the fusion of a B cell (producing a specific antibody) and a myeloma cell.
2. Choice C is correct because hybridomas can be immortalized and cultured indefinitely.
3. Choice A is incorrect because hybridomas produce monoclonal antibodies, not polyclonal antibodies.
4. Choice B is incorrect because hybridomas are formed from a single B cell and a myeloma cell, not two antigen-activated B cells.
5. Choice D is incorrect as only option C accurately describes a hybridoma's characteristic of indefinite tissue culture survival.
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.
Which of the following best describes granuloma formation?
- A. IgE-mediated mast cell activation
- B. Persistent recruitment of macrophages around undigested antigens
- C. Deposition of immune complexes in tissues
- D. Complement-mediated cell lysis
Correct Answer: B
Rationale: Granuloma formation is characterized by the persistent recruitment of macrophages around undigested antigens. Initially, macrophages attempt to phagocytose the antigen but fail to digest it completely, leading to the formation of a granuloma. This process is a protective mechanism to isolate the antigen and prevent its spread. IgE-mediated mast cell activation (choice A) is associated with allergic reactions, not granuloma formation. Deposition of immune complexes in tissues (choice C) is linked to immune complex-mediated diseases, not granuloma formation. Complement-mediated cell lysis (choice D) involves the destruction of target cells by the complement system, which is not directly related to granuloma formation.
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.
A nurse is taking care of a client with cancer and is teaching about the types of drugs that promote the natural production of blood cells in people whose own hematopoietic functions have become compromised. What class of drugs are these?
- A. Tumor necrosis factors
- B. Colony-stimulating factors
- C. Interferons
- D. Interleukins
Correct Answer: B
Rationale: Colony-stimulating factors stimulate the production of blood cells which is crucial for clients with compromised hematopoietic function such as those undergoing chemotherapy.