Passive immunity

Definition

Passive immunity is the transfer of active humoral immunity in the form of ready-made antibodies from one individual to another. This type of immunity provides immediate, but short-lived protection against pathogens.

5 Must Know Facts For Your Next Test

1. Passive immunity can be naturally acquired through maternal antibodies passed to a baby via the placenta and breast milk.
2. It can also be artificially acquired through antibody-containing blood products such as immune globulin.
3. Unlike active immunity, passive immunity does not require exposure to the antigen and does not result in memory cell formation.
4. Passive immunity is crucial for individuals with compromised immune systems who cannot produce their own adequate immune response.
5. The duration of passive immunity is typically short, lasting only a few weeks to months, because the transferred antibodies are eventually degraded.

Review Questions

• What are two ways passive immunity can be acquired?
• Why doesn't passive immunity result in long-term protection?
• For whom is passive immunity particularly important and why?

Related terms

Active Immunity: Long-lasting protection resulting from the body's own immune response to an antigen, including memory cell formation.

Antibodies: Proteins produced by B cells that recognize and neutralize specific antigens.

Immune Globulin: A blood product containing pooled antibodies used for providing immediate but temporary immune protection.