Memory T cells provide long-term immunity by remaining in the body after an infection and responding more rapidly upon re-exposure to the same pathogen.
Correct Answer: B — Long-term immunity
Q. What is the primary function of T helper cells in the immune response?
A.Directly kill infected cells
B.Activate B cells and cytotoxic T cells
C.Produce antibodies
D.Phagocytize pathogens
Solution
T helper cells play a crucial role in the immune response by activating B cells to produce antibodies and cytotoxic T cells to kill infected cells.
Correct Answer: B — Activate B cells and cytotoxic T cells
Q. What is the primary purpose of vaccination?
A.To treat existing infections
B.To induce passive immunity
C.To stimulate an adaptive immune response
D.To enhance innate immunity
Solution
Vaccination aims to stimulate an adaptive immune response by exposing the immune system to a harmless form of the pathogen, leading to the development of memory.
Correct Answer: C — To stimulate an adaptive immune response
Q. What is the role of antibodies in the immune response?
A.Directly kill pathogens
B.Neutralize toxins and pathogens
C.Activate complement system
D.All of the above
Solution
Antibodies play multiple roles in the immune response, including neutralizing toxins and pathogens, opsonizing for phagocytosis, and activating the complement system.
Correct Answer: D — All of the above
Q. What is the role of dendritic cells in the immune system?
A.Produce antibodies
B.Present antigens to T cells
C.Kill pathogens directly
D.Secrete cytokines
Solution
Dendritic cells are professional antigen-presenting cells that capture, process, and present antigens to T cells, initiating the adaptive immune response.
Correct Answer: B — Present antigens to T cells
Q. Which cytokine is primarily responsible for the differentiation of naive T cells into Th1 cells?
A.IL-4
B.IL-12
C.IFN-gamma
D.TNF-alpha
Solution
IL-12 is the key cytokine that promotes the differentiation of naive T cells into Th1 cells, which are important for cell-mediated immunity.
Correct Answer: B — IL-12
Q. Which immune cells are primarily involved in the clearance of intracellular pathogens?
A.B cells
B.Cytotoxic T cells
C.Helper T cells
D.Natural killer cells
Solution
Cytotoxic T cells are primarily responsible for recognizing and killing cells infected with intracellular pathogens, such as viruses.
Correct Answer: B — Cytotoxic T cells
Q. Which of the following is NOT a characteristic of the adaptive immune response?
A.Specificity
B.Memory
C.Immediate response
D.Clonal expansion
Solution
The adaptive immune response is characterized by specificity, memory, and clonal expansion, but it is not immediate; it takes time to develop.
Correct Answer: C — Immediate response
Q. Which type of immunity is conferred by the transfer of maternal antibodies to the fetus?
A.Active immunity
B.Passive immunity
C.Innate immunity
D.Cell-mediated immunity
Solution
Passive immunity is conferred by the transfer of maternal antibodies to the fetus, providing temporary protection against infections.
Correct Answer: B — Passive immunity
Q. Which type of immunity is primarily mediated by antibodies?
A.Cell-mediated immunity
B.Humoral immunity
C.Innate immunity
D.Passive immunity
Solution
Humoral immunity is primarily mediated by antibodies produced by B cells, which help neutralize pathogens and mark them for destruction.
