[Campbell Biology P.1001] An individual previously infected with Influenza virus strain 1 Ser... | Practice Question

An individual previously infected with Influenza virus strain 1 Ser Tyr Pro Lys Leu Lys Asn is later exposed to a new influenza virus strain with a surface protein sequence of Ser Tyr Pro Asn Leu Ser Asn. Based on the 'Adaptive recognition' section and the accompanying image, what is most likely true regarding the adaptive immune response to this new strain?

  • A: The adaptive immune system will not recognize the new strain at all due to the sequence differences.
  • B: The adaptive immune system will recognize the new strain with the same receptor used for strain 1 because they are both influenza viruses.
  • C: A different adaptive immune receptor is likely required to recognize the new strain due to variations in the amino acid sequence at positions colored orange.
  • D: Innate immunity will be the primary defense, as adaptive immunity only recognizes the initial strain encountered.

Explanation

The 'Adaptive recognition' section states that 'a different adaptive immune receptor would recognize each of the flu strains based on the proteins' amino acid sequences, which differ at the positions colored orange.' The new strain presented Ser Tyr Pro Asn Leu Ser Asn has differences at positions 4 Lys vs. Asn and 6 Lys vs. Ser compared to strain 1, and position 5 Lys vs. Ser compared to strain 2, aligning with the concept that sequence variations necessitate new, specific receptors.