Question

Why do we say that if a person is suffers from chickenpox once, he or she is not likely to be attacked by the same disease in future

Answer 1

I think that it is to do with memory lymphocytes, but I'm not exactly sure. The first time someone is infected with chicken pox, the lymphocyte (white blood cell) that has the antibodies against the antigens on the chicken pox cells will rapidly reproduce, and the antibodies will neutralise the pathogen. They then send out chemical messages so that phagocytes come to engulf and digest the lymphocyte-pathogen complex. Through this process, many of these lymphocytes are digested, however, some inactive ones remain in the blood. So, when the chicken pox pathogen enters the body again, these lymphocytes can reproduce faster and the immune response occurs before the pathogen can harm the body again. Hope that helps!