Which antibody dominates the primary immune response?
- A. IgG
- B. IgA
- C. IgM
- D. IgE
Correct Answer: C
Rationale: The correct answer is C: IgM. During the primary immune response, IgM is the first antibody produced by the immune system in response to an antigen. IgM is efficient in agglutination and complement fixation, aiding in the elimination of pathogens. IgG is more prominent in the secondary immune response. IgA is mainly found in mucosal areas. IgE is associated with allergic reactions and parasitic infections, not the primary immune response. So, IgM dominates the primary immune response by being the initial antibody produced to combat antigens.
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To what is the increase in emerging and untreatable infections attributed (select all that apply)?
- A. The evolution of new infectious agents
- B. Use of antibiotics to treat viral infections
- C. Human population encroachment into wilderness areas
- D. Transmission of infectious agents from humans to animals
Correct Answer: A
Rationale: The correct answer includes options A, B, C, and E. The evolution of new infectious agents, inappropriate use of antibiotics, human encroachment into wilderness areas, and an increased number of immunosuppressed individuals contribute significantly to the rise in untreatable infections. Transmission from humans to animals is less relevant compared to zoonotic transmission from animals to humans.
An immune response to polysaccharide subunit vaccines can be obtained
- A. If the vaccines is administered with adjuvants
- B. Only after multiple booster injections
- C. Only if administered orally
- D. If the polysaccharide subunit is coupled to a protein carrier
Correct Answer: D
Rationale: The correct answer is D because coupling the polysaccharide subunit to a protein carrier enhances the immune response by converting the T-independent response to a T-dependent response. This allows for the induction of memory B cells and long-lasting immunity. Adjuvants (choice A) may enhance immune response but are not essential for polysaccharide-protein conjugate vaccines. Multiple booster injections (choice B) are not required for polysaccharide-protein conjugate vaccines as a single dose can induce a robust immune response. Administering orally (choice C) is not the only route for obtaining an immune response to polysaccharide subunit vaccines.
Which complement protein is the main component of the Membrane Attack Complex (MAC)?
- A. C1
- B. C3
- C. C5b
- D. C4b
Correct Answer: C
Rationale: The correct answer is C: C5b. The Membrane Attack Complex (MAC) is formed by a sequence of complement proteins, with C5b playing a crucial role as the initiator. After C5b binds to the target cell membrane, it triggers the assembly of C6, C7, C8, and multiple C9 molecules to form the MAC pore. C1 (A) is the initiator of the classical pathway, not a component of the MAC. C3 (B) is involved in the formation of the C3 convertase and opsonization but is not the main component of the MAC. C4b (D) is part of the classical pathway and is involved in the formation of the C3 convertase, not the MAC.
T cells help B cells to:
- A. Undergo isotype switching
- B. Produce antibodies against protein antigens
- C. Receive signal 2 of activation
- D. All of the above
Correct Answer: D
Rationale: The correct answer is D, "All of the above." T cells help B cells undergo isotype switching by providing cytokines. They also help B cells produce antibodies against protein antigens by activating them. T cells provide signal 2 of activation to B cells through the interaction of CD40 on B cells with CD40L on T cells. Therefore, all of these functions are critical for the collaboration between T and B cells in the immune response.
A 26-year-old man was adopted. What health information related to his biological parents and family will be most useful to him when he gets married (select all that apply)?
- A. Cholecystitis occurring in family members
- B. Occurrence of prostate cancer in one uncle
- C. Ages of family members diagnosed with diseases
- D. Kidney stones present in extended family members
Correct Answer: C
Rationale: Information about specific diseases like prostate cancer, ages of diagnosis, and causes of death provide critical insights into potential hereditary risks, making them highly relevant for future health planning.