A brief explanation occurs for this question:
Every year new flu viruses arise in the world, and yet most of the time we have one or more lymphocytes that can respond to these new viruses. How is this so?© BrainMass Inc. brainmass.com October 9, 2019, 9:23 pm ad1c9bdddf
If our body encounter the same flu virus which one has encountered earlier, the memory cell is capable of producing defense mechanism on immediate basis. ...
New flu viruses are asssessed.