ATI Pathophysiology Practice Exam

Active immunity is acquired through vaccination because it involves the body’s immune system creating a response after exposure to a vaccine. Vaccines contain antigens that stimulate the immune system to recognize and fight off pathogens, similar to how it would respond to an actual infection. This exposure leads to the production of memory cells, which allows the body to mount a faster and more effective response if it encounters the real pathogen in the future.

In contrast, passive immunity is achieved through the transfer of antibodies from one individual to another, such as during breastfeeding or through antibody treatments, and does not involve the recipient's immune system actively creating a response. Innate immunity refers to the first line of defense against pathogens that is present at birth and includes physical barriers like skin and immune cells that respond to all pathogens in the same way. Cell-mediated immunity specifically involves T cells responding to infections, but it is not what is gained directly from vaccination, which typically aims to stimulate a broader adaptive immune response that includes both humoral (antibody-mediated) and cellular immunity.