Passive Immunity in Newborns

Steps:

• Passive immunity occurs when antibodies from an external source, like the mother, provide temporary protection to the newborn via placenta or breast milk.
• These maternal antibodies circulate in the baby's bloodstream but are not produced by the baby's immune system.
• Over time, the baby's body metabolizes and breaks down these foreign antibodies.
• Once broken down, the immunity fades, lasting only months until the baby develops its own active immunity.

Why A is correct:

• By definition, passive immunity is temporary because the transferred antibodies are gradually broken down by the recipient's body, providing short-term protection without long-term memory.

Why the others are wrong:

• B: Antibodies are broken down, making the immunity temporary.
• C: Immunity is temporary, not lifelong.
• D: Both immunity and antibodies are temporary in passive transfer.

Final answer: A