Antigenic Variation

• What is an antigenic variation?

  Changes in antigens on pathogen surfaces
• How do antigens on pathogens affect the immune response?

  They activate the primary immune response
• What happens when you are infected a second time with the same pathogen?

  They activate the secondary immune response
• What is the significance of some pathogens changing their surface antigens?

  It leads to antigenic variation
• What causes different antigens to be formed on pathogens?

  Changes in the genes of a pathogen
• Why must the immune system start from scratch when reinfected with a pathogen that has changed its antigens?

  Memory cells cannot recognize new antigens
• What happens to memory cells produced from the first infection?

  They do not recognize different antigens
• What is the impact of antigenic variation on vaccine development?

  It complicates the development of effective vaccines
• How does antigenic variation affect the production of vaccines against influenza?

  Vaccines must be updated regularly
• What does the changing of antigens on the influenza virus lead to?

  Formation of new strains of the virus
• Why do new strains of the influenza virus emerge every year?

  Antigens on the virus change regularly
• How does antigenic variation affect public health measures against influenza?

  It requires annual vaccination updates
• What is the consequence of antigenic variation for individuals?

  Increased risk of reinfection with the same virus
• What is the primary reason for the difficulty in developing vaccines against some pathogens?

  Antigenic variation complicates vaccine effectiveness
• How does antigenic variation influence the immune response over time?

  It leads to a need for new immune strategies
• What is the relationship between antigenic variation and the effectiveness of public health campaigns?

  It necessitates ongoing updates to health strategies
• What is the purpose of vaccines in relation to influenza?

  To help prevent people catching influenza
• How does the influenza vaccine change over time?

  It changes every year due to antigen variation
• Why do new strains of the influenza virus form regularly?

  Because the antigens on the virus surface change
• What happens to memory cells produced from vaccination against one strain of influenza?

  They do not recognize different strains with varying antigens
• How are the strains of the influenza virus characterized?

  They are immunologically distinct from each other
• What does the circulation of different influenza strains in the population imply?

  A different vaccine must be developed each year
• What is the role of governments and health authorities regarding influenza vaccination?

  To implement vaccination programs using suitable vaccines
• What are the two types of influenza infections mentioned?

  1. First infection - triggers a primary response
  2. Second infection - triggers a primary response
• What is the term for the variation in antigens of the influenza virus?

  Antigenic variation
• How does antigenic variation affect vaccine effectiveness?

  It necessitates the development of new vaccines
• What is illustrated in Figure 2 regarding the influenza virus?

  Antigenic variation in the influenza virus