Immunology and Serology Flashcards
7 cards from real Medical Laboratory Technician Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Immunology and Serology flashcards as text
Which type of hypersensitivity reaction is responsible for contact dermatitis caused by poison ivy?
Answer: Type IV – delayed-type (cell-mediated)
Contact dermatitis is a Type IV (delayed-type) hypersensitivity reaction mediated by sensitized T lymphocytes, not antibodies.
A positive tuberculin (PPD) skin test reaction is read at 48–72 hours and is an example of which immune mechanism?
Answer: T cell–mediated delayed hypersensitivity
PPD testing relies on Type IV delayed hypersensitivity; sensitized CD4+ T cells release cytokines causing induration at the injection site.
Which of the following is a characteristic of the alternative pathway of complement activation?
Answer: Is spontaneously activated on microbial surfaces lacking regulatory proteins
The alternative pathway activates spontaneously via continuous low-level C3 hydrolysis and amplifies on surfaces lacking complement regulatory proteins.
Anti-centromere antibodies detected by ANA testing are most specifically associated with which disease?
Answer: Limited cutaneous systemic sclerosis (CREST syndrome)
Anti-centromere antibodies are highly specific for limited cutaneous systemic sclerosis (CREST syndrome).
In flow cytometry, fluorochromes are excited by which energy source?
Answer: Laser beam
Flow cytometers use one or more lasers to excite fluorochromes conjugated to antibodies, and detectors measure emitted fluorescence.
A patient with recurrent sinopulmonary infections, normal B and T cell counts, but absent germinal centers and low IgG/IgA/IgM most likely has:
Answer: Common variable immunodeficiency (CVID)
CVID is characterized by low immunoglobulins with normal B and T cell numbers but defective antibody production, typically presenting in young adults.
In an indirect fluorescent antibody (IFA) test, the patient's antibody is detected using:
Answer: A fluorescently labeled anti-human immunoglobulin
IFA uses a fluorescently labeled secondary antibody (anti-human Ig) to detect patient antibody bound to substrate antigen.