MLPAO MLPAO Immunology and Serology

Question 1

Which immunoglobulin class is the first to be produced during a primary immune response?

Accepted Answer

IgM

Answer

IgM is the first antibody class produced during a primary immune response due to its pentameric structure that allows effective complement activation before affinity maturation occurs.

Question 2

In the complement system, which pathway is activated by antigen-antibody complexes?

Accepted Answer

Classical pathway

Answer

The classical pathway is activated by antigen-antibody (immune) complexes when IgG or IgM antibodies bind to C1q, initiating the complement cascade.

Question 3

A patient's serum is tested by ELISA for HIV antibodies. Which component is coated onto the microplate wells?

Accepted Answer

HIV antigens

Answer

In an indirect ELISA for antibody detection, the target antigen (HIV proteins) is coated onto the plate to capture any specific antibodies present in the patient's serum.

Question 4

Which type of hypersensitivity reaction is responsible for anaphylaxis?

Accepted Answer

Type I (immediate)

Answer

Type I (immediate) hypersensitivity is IgE-mediated and causes mast cell degranulation, releasing histamine and other mediators that produce anaphylaxis within minutes.

Question 5

The prozone phenomenon in serology occurs when:

Accepted Answer

Antibody is in great excess, preventing lattice formation

Answer

Prozone occurs when antibody is in great excess relative to antigen, causing all antigen sites to be occupied by individual antibodies rather than forming the cross-linked lattice needed for visible agglutination.

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO - Medical Laboratory Professionals Association of Ontario Practice Test

MLPAO MLPAO Immunology and Serology