Question 1

Which of the following best describes the difference between affinity and avidity in antigen-antibody interactions?

Accepted Answer

Affinity is the strength of binding between an antibody and a single epitope, while avidity is the overall binding strength of an antibody to a multivalent antigen.

Question 2

In a direct Coombs test, which of the following is detected?

Accepted Answer

Antibodies already bound to the patient's red blood cells (RBCs).

Question 3

Which laboratory technique is commonly used as a confirmatory test for HIV infection after a positive ELISA result?

Accepted Answer

Western blot

Question 4

A patient’s serum is tested for the presence of anti-nuclear antibodies (ANA) using indirect immunofluorescence. Which of the following best describes the process?

Accepted Answer

Patient serum is added to a slide with fixed cells, followed by a fluorescently labeled secondary antibody that binds to human antibodies.

Question 5

Which of the following is a key step in the production of monoclonal antibodies using hybridoma technology?

Accepted Answer

Fusion of myeloma cells with primed B cells to create immortalized hybridoma cells.

Question 6

In the context of autoimmune hemolytic anemia, which mechanism is primarily responsible for the destruction of red blood cells?

Accepted Answer

Activation of the complement cascade leading to cell lysis.

Question 7

Which of the following best explains why autoimmune diseases are more common in women than men?

Accepted Answer

Women have a larger X chromosome with more immune-related genes and stronger humoral and cellular immune responses.

Question 8

A patient with Graves’ disease is likely to present with which of the following symptoms due to excessive thyroid hormone production?

Accepted Answer

Heat intolerance and weight loss

Question 9

Which of the following statements about the ELISA (Enzyme-Linked Immunosorbent Assay) is correct?

Accepted Answer

Indirect ELISA detects antibodies in a patient's serum using a labeled secondary antibody.

Question 10

Which of the following is a major contributor to beta cell destruction in Type 1 Diabetes Mellitus (T1DM)?

Accepted Answer

Cytotoxic CD8+ T cells

Question 11

A patient with systemic lupus erythematosus (SLE) is found to have anti-double stranded DNA antibodies. What is the most likely consequence of these antibodies?

Accepted Answer

Formation of immune complexes that deposit in the glomerular basement membrane, leading to kidney damage.

Question 12

Which of the following best describes the principle of flow cytometry in immunology?

Accepted Answer

It uses fluorescently labeled antibodies to analyze and sort cells based on surface markers.

Question 13

Which of the following is a diagnostic application of monoclonal antibodies?

Accepted Answer

Detection of human chorionic gonadotropin (hCG) in urine for pregnancy testing.

Question 14

In a Western blot assay, what is the primary purpose of transferring proteins from a gel to a nitrocellulose sheet?

Accepted Answer

To allow antibodies to bind to specific proteins for detection.

Question 15

Which of the following is a therapeutic use of monoclonal antibodies?

Accepted Answer

Immunotoxins targeting tumor cells

Question 16

A patient with myasthenia gravis has autoantibodies directed against acetylcholine receptors. What is the primary effect of these autoantibodies?

Accepted Answer

Inhibition of nerve impulse transmission across the neuromuscular junction.

Question 17

Which of the following is a common symptom of Hashimoto’s thyroiditis?

Accepted Answer

Weight gain and cold intolerance

Question 18

In rheumatoid arthritis (RA), which immune cells are primarily involved in the chronically inflamed synovium?

Accepted Answer

T cells, B cells, macrophages, and plasma cells

Question 19

Which of the following best explains the increased risk of autoimmune diseases during pregnancy?

Accepted Answer

Reduction in maternal immune response is compensated by increased activity of immune system factors in women.

Question 20

Which equation best represents the total binding strength (avidity) of an antibody with 10 antigen-binding sites, each with an affinity constant $$K_a$$?

Accepted Answer

$$Avidity = 10 	imes K_a$$

Immunological Assays and Autoimmune Diseases: Microbiology Study Notes

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