Chapter 41 - Immunology: Animal defense Systems - 41.3 Adaptive Defenses Are Specific - 41.3 Recap - Learning Outcomes - Page 877: 2

The older individuals had memory cells which were capable of making antibodies to bind to the 1918 flu strain. The 1918 flu strain was very similar to the 2009 virus strain, which is why these older individuals' immune systems were able to fend off this 2009 strain.

The older individuals had memory cells which were capable of making antibodies to bind to the 1918 flu strain. The 1918 flu strain was very similar to the 2009 virus strain, which is why these older individuals' immune systems were able to fend off this 2009 strain.