One of the unique features of the immune system is its ability to remember pathogens that it successfully combatted; this is why people typically don’t get the same cold virus twice or suffer a repeat bout of chicken pox. Lymphocytes allow the body to remember former invaders. Should these pathogens attack again, the lymphocytes trigger an immediate response. There are two types of lymphocytes in the body: B lymphocytes and T lymphocytes. The former produce antibodies; the latter destroy damaged cells in the body.

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