Question VIII. Reasons complicating the development of vaccines to combat chroni

Question

Question VIII. Reasons complicating the development of vaccines to combat chronic diseases include [complete the sentence and assess each subsequent statement (63- 67) as either factually correct (= “true”) or incorrect (= “false”)]:
63. evasion of the host’s immune system by the pathogen.

64. the polymorphic diversity of MHC class I and class II molecules.
65. the generation of inappropriate immune responses that do not eradicate the pathogen.
66. survival of the infectious agent for long periods inside the host.
67. high mutation rates in the pathogens.

Explanation / Answer

63. Reasons complicating the development of vaccines to combat chronic diseases include evasion of the host’s immune system by the pathogen. – True

Reason: Immune system of the host provides defence against the invasion of pathogens. Vaccines work as dummy pathogens and awoke immune response. But in some cases the host’s immune system itself gets infected by the pathogen. In such cases, vaccine development becomes more complicated.

64. Reasons complicating the development of vaccines to combat chronic diseases include the polymorphic diversity of MHC class I and class II molecules. – True

Reason: MHC class I and class II molecules show vast diversity. For each pathogen, host cells and immune cells produce vast number of MHC class I and class II molecules. So, it is very difficult to produce a single vaccine for diversified MHC molecules.

65. Reasons complicating the development of vaccines to combat chronic diseases include the generation of inappropriate immune responses that do not eradicate the pathogen. – True

Reason: some pathogens hide the antigens and imitate others to elicit host’s immune system in a wrong way to avoid the immune response. This makes the development of vaccines more complicated.

66. Reasons complicating the development of vaccines to combat chronic diseases include survival of the infectious agent for long periods inside the host. –True

Reason: This is true because, host’s immune system produces antibodies against and pathogens. If still the pathogen is existing in the host for a longer period, it is clear that the immune system is simply failed. Vaccines work by stimulating immune system. Failed immune system cannot respond for new vaccines.

67. Reasons complicating the development of vaccines to combat chronic diseases include high mutation rates in the pathogen. – True.

Reason: Mutations rapidly change the pathogen’s antigenic nature and hence make it more difficulty to develop vaccines.

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