Difficulty: Medium

Average Score: 54%

Which of the following best describes protection from antigens due to passive immunity?

Rationale

A mother passes antibodies to her child through breast milk.

Passive immunity occurs when antibodies are transferred from one individual to another, providing immediate but temporary protection against antigens. This transfer can happen naturally, such as when a mother breastfeeds her child, allowing the infant to receive maternal antibodies that help defend against infections.

A (After primary exposure to an antigen, memory T cells remain to respond to a secondary exposure.) YOUR ANSWER

This statement describes a feature of active immunity rather than passive immunity. Memory T cells are generated after an individual’s immune system has actively encountered an antigen, allowing for a quicker and stronger response upon subsequent exposures. Passive immunity, in contrast, does not involve the host's immune system actively producing memory cells.

B (Exposure to a virus leads to the production of antibodies that can bind to the virus.) YOUR ANSWER

This choice refers to the process of active immunity, where an immune response is generated following exposure to a pathogen, resulting in the production of specific antibodies. Passive immunity involves the direct transfer of antibodies rather than the host producing them in response to an infection.

C (Immunization leads to the activation of B-cell proliferation.) YOUR ANSWER

While immunization does stimulate B-cell proliferation to produce antibodies, this describes the mechanism of active immunity. In active immunity, the immune system learns to recognize and respond to specific antigens, whereas passive immunity relies on the transfer of pre-formed antibodies without requiring an immune response.

Conclusion

Passive immunity is characterized by the direct transfer of antibodies, such as when a mother transfers antibodies to her child through breast milk. This method provides temporary protection, allowing infants to benefit from their mother’s immune defenses while their own immune systems are still developing. Active immunity, in contrast, involves the body's own immune response to antigens, leading to the production of memory cells and antibodies.

Related Questions

View all