哺乳動物血液的防禦功能：练习题

• a.

  The injected antibodies are gradually broken down and no memory cells are produced to replace them.

• b.

  The T cells involved in passive immunity have a shorter lifespan than the B cells involved in active immunity.

• c.

  The antiserum contains antigens that the body eventually destroys, preventing further immune response.

• d.

  The antibodies in the antiserum undergo somatic hypermutation, making them less effective against the specific pathogen.

• a.

  They fuse with the phagocytic vacuole and release hydrolytic enzymes that digest the bacterial cell wall and components.

• b.

  They produce hydrogen peroxide which is secreted outside the cell to kill bacteria before they are engulfed.

• c.

  They secrete antibodies into the cytoplasm of the phagocyte to neutralize bacterial toxins.

• d.

  They move to the cell surface membrane to act as receptors for the bacterial antigens during initial attachment.

• a.

  The complex prevents the pathogen from undergoing binary fission by blocking the replication of plasmids.

• b.

  The complex acts as a catalyst for the hydrolysis of murein in the bacterial cell wall, causing immediate lysis.

• c.

  The antibody molecules inject toxins directly into the pathogen through the antigen binding site.

• d.

  The complex leads to the agglutination of bacterial cells, making them easier for phagocytes to locate and ingest.

• a.

  The virus produces toxins that neutralize the antibodies before they can form an antigen-antibody complex.

• b.

  Mutations in the viral genome change the tertiary structure of surface proteins, so memory cells from previous infections no longer recognize the antigens.

• c.

  The virus destroys the host’s plasma cells, preventing the secondary immune response from occurring.

• d.

  The viral DNA integrates into the host chromosome and inhibits the production of MHC complexes by the B cells.

先自己写一遍答案，再对照解题步骤。

先自己写一遍答案，再对照解题步骤。