BIOS 242 EXAM 3 KEY CONCEPTS AND
PRACTICE QUESTIONS
◉ What substance, released by virus-infected cells, signals
neighboring cells to produce antiviral proteins?
Answer: Type I interferon
◉ How does the complement system's membrane attack complex
(MAC) cause microbial death?
Answer: It creates pores in the microbial membrane, causing lysis.
◉ Which immunoglobulin class is found in highest concentration in
secretions like saliva, tears, and breast milk?
Answer: IgA
◉ How does the secondary immune response differ from the
primary response?
Answer: It is faster and produces higher levels of antibody due to the
presence of memory cells.
◉ What is a hapten?
,Answer: A small molecule that becomes antigenic only when bound
to a larger carrier protein.
◉ Why are CD4+ helper T cells essential to both cell-mediated and
humoral immunity?
Answer: They release cytokines that activate both cytotoxic T cells
and B cells.
◉ Which immunoglobulin class is the first to be produced following
initial antigen exposure and is the best agglutinator?
Answer: IgM
◉ Receiving Rh-immune globulin (RhoGAM) is an example of which
type of immunity?
Answer: Artificially acquired passive immunity
◉ Protection against tetanus via maternal IgG antibodies crossing
the placenta is an example of what type of immunity?
Answer: Naturally acquired passive immunity
◉ Which complement activation pathway is triggered by antigen-
antibody complexes?
Answer: Classical pathway
, ◉ What is the primary effect of histamine release by basophils at an
infection site?
Answer: It increases vascular permeability and promotes
inflammation.
◉ On which cells are MHC class II molecules found, and to which T
cell subset do they present antigens?
Answer: They are found on antigen-presenting cells (APCs) and
present antigens to CD4+ helper T cells.
◉ An eosinophil is most important in the defense against which type
of pathogen?
Answer: Multicellular parasites (helminths)
◉ Which infection should be suspected in a patient with rapidly
spreading necrosis of the skin and fascia, severe pain, and
hypotension?
Answer: Necrotizing fasciitis due to Streptococcus pyogenes
◉ Which virulence factor of Streptococcus pyogenes is most
responsible for the spread of the organism through tissue planes?
Answer: Hyaluronidase
PRACTICE QUESTIONS
◉ What substance, released by virus-infected cells, signals
neighboring cells to produce antiviral proteins?
Answer: Type I interferon
◉ How does the complement system's membrane attack complex
(MAC) cause microbial death?
Answer: It creates pores in the microbial membrane, causing lysis.
◉ Which immunoglobulin class is found in highest concentration in
secretions like saliva, tears, and breast milk?
Answer: IgA
◉ How does the secondary immune response differ from the
primary response?
Answer: It is faster and produces higher levels of antibody due to the
presence of memory cells.
◉ What is a hapten?
,Answer: A small molecule that becomes antigenic only when bound
to a larger carrier protein.
◉ Why are CD4+ helper T cells essential to both cell-mediated and
humoral immunity?
Answer: They release cytokines that activate both cytotoxic T cells
and B cells.
◉ Which immunoglobulin class is the first to be produced following
initial antigen exposure and is the best agglutinator?
Answer: IgM
◉ Receiving Rh-immune globulin (RhoGAM) is an example of which
type of immunity?
Answer: Artificially acquired passive immunity
◉ Protection against tetanus via maternal IgG antibodies crossing
the placenta is an example of what type of immunity?
Answer: Naturally acquired passive immunity
◉ Which complement activation pathway is triggered by antigen-
antibody complexes?
Answer: Classical pathway
, ◉ What is the primary effect of histamine release by basophils at an
infection site?
Answer: It increases vascular permeability and promotes
inflammation.
◉ On which cells are MHC class II molecules found, and to which T
cell subset do they present antigens?
Answer: They are found on antigen-presenting cells (APCs) and
present antigens to CD4+ helper T cells.
◉ An eosinophil is most important in the defense against which type
of pathogen?
Answer: Multicellular parasites (helminths)
◉ Which infection should be suspected in a patient with rapidly
spreading necrosis of the skin and fascia, severe pain, and
hypotension?
Answer: Necrotizing fasciitis due to Streptococcus pyogenes
◉ Which virulence factor of Streptococcus pyogenes is most
responsible for the spread of the organism through tissue planes?
Answer: Hyaluronidase
