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Chapter 17

25 February, 2016 - 11:05
  1. Figure 17.5 D
  2. Figure 17.6 The host cell can continue to make new virus particles.
  3. Figure 17.21 If the blood of the mother and fetus mixes, memory cells that recognize the Rh antigen of the fetus can form in the mother late in the first pregnancy. During subsequent pregnancies, these memory cells launch an immune attack on the fetal blood cells of an Rh-positive fetus. Injection of anti-Rh antibody during the first pregnancy prevents the immune response from occurring.
  4. B
  5. D
  6. B
  7. A
  8. B
  9. C
  10. C
  11. C
  12. A
  13. D
  14. B
  15. C
  16. The virus cannot attach to dog cells because dog cells do not express the receptors for the virus or there is no cell within the dog that is permissive for viral replication.
  17. Rabies vaccine works after a bite because it takes two weeks for the virus to travel from the site of the bite to the central nervous system, where the most severe symptoms of the disease occur. The vaccine is able to cause an immune response in the body during this time that clears the infection before it reaches the nervous system.
  18. If the MHC class I molecules expressed on donor cells differ from the MHC class I molecules expressed on recipient cells, NK cells may identify the donor cells as not normal and produce enzymes to induce the donor cells to undergo apoptosis, which would destroy the transplanted organ.
  19. The entire complement system would probably be affected even when only a few members were mutated such that they could no longer bind. Because the complement involves the binding of activated proteins in a specific sequence, when one or more proteins in the sequence is absent, the subsequent proteins would be incapable of binding to elicit the complement’s pathogen- destructive effects.
  20. T cells bind antigens that have been digested and embedded in MHC molecules by APCs. In contrast, B cells function as APCs to bind intact, unprocessed antigens.
  21. Upon reinfection, the memory cells will immediately differentiate into plasma cells and CTLs without input from APCs or TH cells. In contrast, the adaptive immune response to the initial infection requires time for naïve B and T cells with the appropriate antigen specificities to be identified and activated.
  22. This is probably a delayed sensitivity reaction to one or more chemicals in the developer. An initial exposure would have sensitized the individual to the chemical and then subsequent exposures will induce a delayed inflammation reaction a day or two after exposure.