Which type of immunity does NOT lead to memory formation?

Which type of immunity does NOT lead to memory formation?

• A. Natural active
• B. Artificial active
• C. Passive immunity
• D. Natural passive

Answer: (C)

Passive immunity is characterized by the transfer of antibodies from one individual to another, providing immediate protection against pathogens without the recipient's immune system having to actively respond or produce its own antibodies. This type of immunity can occur naturally, such as when antibodies are passed from mother to child through the placenta or breast milk, or artificially, such as through the injection of antibodies (gamma globulin therapy).

Since passive immunity involves the acquisition of antibodies directly, rather than stimulating the immune system to produce its own, it does not lead to the formation of immunological memory. As a result, the immune system does not remember the exposure to the pathogen, and the protection offered is temporary, lasting only as long as the transferred antibodies are present in the body.

In contrast, both natural and artificial active immunity involve exposure to antigens, whether through infection or vaccination, leading to the generation of memory cells that enable a quicker and more effective response upon subsequent encounters with the same pathogen.