How does passive immunotherapy primarily differ from active immunotherapy?

Passive immunotherapy primarily differs from active immunotherapy in its ability to generate immunologic memory. Active immunotherapy involves stimulating the immune system to produce its own antibodies or activate T-cells against specific antigens, resulting in a long-lasting immune response and the formation of memory cells. This means that if the body encounters the same antigen again in the future, it can mount a quicker and more effective immune response.

In contrast, passive immunotherapy involves the administration of pre-formed antibodies or immune cells from an external source. While it can provide immediate protection or therapeutic effect, it does not lead to the development of immune memory. As a result, once the administered antibodies in passive immunotherapy are cleared from the body, there is no sustained protective immune response against the target antigens.

Understanding this fundamental difference helps emphasize the distinct roles and applications of each type of immunotherapy in treatment settings.