Which of the following best distinguishes vaccines from antitoxins in the context of immunity?

• A. Antitoxins stimulate memory cell formation, while vaccines do not.
• B. Vaccines are used only after infection has occurred, whereas antitoxins are used for prevention.
• C. Both vaccines and antitoxins provide long-lasting active immunity.
• D. Vaccines stimulate the immune system to produce its own antibodies, while antitoxins provide pre-formed antibodies to neutralize toxins.

Answer: (D)

Verified step by step guidance

1. Understand the definitions: Vaccines are biological preparations that stimulate the immune system to produce its own antibodies and memory cells, leading to active immunity.
2. Recognize that antitoxins are preparations containing pre-formed antibodies, which provide immediate passive immunity by neutralizing toxins without stimulating the recipient's immune system.
3. Compare the type of immunity provided: Vaccines induce active immunity, which is long-lasting due to memory cell formation, whereas antitoxins provide passive immunity, which is immediate but temporary.
4. Analyze the timing of use: Vaccines are typically administered before exposure to a pathogen to prevent disease, while antitoxins are often used after exposure to neutralize toxins quickly.
5. Conclude that the key distinction is that vaccines stimulate the body's own immune response to produce antibodies, whereas antitoxins supply ready-made antibodies externally.