Evolution Of Pathogens

Question 1

What is an evolutionary race

Answer 1

Interaction/battle between vertebrates evolving better immune systems (fight greater variety of pathogens in lots of different ways) and pathogens evolving better and better ways to evade the immune systems of their hosts

Question 2

What are HIV’s evasion mechanisms

Answer 2

-kills the immune system cells it infects= reducing the overall number of immune systems cells reducing the chance of HIV being detected
-has a high rate of mutation in the genes that code for antigen proteins, change the structure of the antigens and forms new strains of the virus (antigenic variation, memory cells produced for one strain of HIV won’t recognise other strains with dif antigens so immune system has to produce primary response against each new strain)
-disrupts antigen presentation in infected cells= prevents immune system cells from recognising and killing the infected cells

Question 3

What is antigenic variation and how is it an evasion mechanism

Answer 3

Mutations in the genes coding for antigen proteins which change the structure of the antigens meaning they form new strains of the virus
-memory cells produced for one strain of HIV won’t recognise other strains with dif antigens to immune system has to produce a primary response against each new strain

Question 4

Mycobacterium tuberculosis’ evasion mechanisms

Answer 4

-when they infect the lungs they’re engulfed by phagocytes and produce substances that prevent the lysosome fusing with the phagocytic vacuole meaning the bacteria aren’t broken down and can multiply undetected inside phagocytes
-disrupts antigen presentation in infected cells which prevents immune system cells from recognising and killing the infected phagocytes