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How does acquired immunity develop after an infection or vaccination?

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Health monitoring — human disease The routine monitoring of blood pressure levels is an important part of assessing an individual's health. Blood pressure provides information about the amount of blood in circulation and about heart function and thus is an important indicator of disease.

Acquired immunity develops when the immune system encounters a specific infectious agent or its products, either through natural infection or vaccination. This process relies on the precise recognition of antigens—foreign substances—by specialized white blood cells called lymphocytes, specifically B cells and T cells.123

When these cells are stimulated, they mount a targeted attack:
* Humoral immunity: B cells mature into plasma cells that secrete antibodies, which bind to antigens to mark invaders for destruction.13
* Cell-mediated immunity: T cells directly attack infected cells or regulate the immune response.3

A critical feature of this development is the creation of immunologic memory. Some B and T cells differentiate into memory cells that persist in the body. If the same pathogen is encountered again, these memory cells enable the immune system to respond much more rapidly and effectively, often preventing disease entirely. Vaccination mimics this process by introducing antigens to stimulate this memory without causing the illness itself.214567