Cells: Cell Recognition & the Immune System - Antigenic Variation

Question 1

What is antigenic variation?

Answer 1

• Antigenic variation is when pathogens change their surface antigens

Question 2

How does this affect the secondary immune response?

Answer 2

• This means when you’re infected for a second time, the memory cells won’t recognise this different antigen
• Immune system has to carry out a primary response against these new antigens
• Primary response takes time and you will get ill again

Question 3

How does antigenic variation affect disease prevention?

Answer 3

• Antigenic variation makes it difficult to develop vaccines against some pathogens
• Examples of pathogens that show antigenic variation include HIV and the influenza virus