Your friend tests her snake-wrangling skills on an eastern diamondback rattlesnake, and is bitten and envenomated (injected with the snake's venom). In the emergency department, doctors administer the antivenin CroFab, which contains antibodies to the toxins in snake venom. Is this an example of active or passive immunity? Will this confer any lasting protection to your friend?

Verified step by step guidance

1. Understand the concept of immunity: Immunity can be classified into active and passive immunity. Active immunity involves the body producing its own antibodies in response to an antigen, while passive immunity involves the direct introduction of antibodies into the body without the immune system actively producing them.
2. Analyze the situation: In this case, the antivenin CroFab contains pre-formed antibodies that neutralize the toxins in the snake venom. These antibodies are not produced by your friend's immune system but are externally provided.
3. Determine the type of immunity: Since the antibodies are introduced directly and not produced by the immune system, this is an example of passive immunity.
4. Evaluate lasting protection: Passive immunity does not confer long-term protection because the externally provided antibodies are temporary and do not stimulate the immune system to produce memory cells. Once the antibodies are metabolized and removed from the body, there is no lasting immunity.
5. Conclude the explanation: Your friend will not have lasting protection against future snake bites from the same species because passive immunity does not involve the development of immunological memory.

Key Concepts

Active Immunity

Active immunity occurs when an individual's immune system is stimulated to produce antibodies in response to an antigen, such as a pathogen or toxin. This can happen naturally through infection or artificially through vaccination. The protection provided by active immunity is usually long-lasting, as the immune system retains memory cells that can respond quickly to future exposures.

Passive Immunity

Passive immunity involves the transfer of antibodies from one individual to another, providing immediate but temporary protection. This can occur naturally, such as when a mother passes antibodies to her baby through breast milk, or artificially through treatments like antivenin. Since the recipient's immune system does not produce its own antibodies, the protection typically lasts only a few weeks to months.

Antivenin (Antivenom)

Antivenin, or antivenom, is a medical treatment that contains antibodies specifically designed to neutralize venom from snake bites or other venomous creatures. In the case of CroFab, it is derived from the plasma of immunized animals and is used to treat envenomation. While it provides immediate protection against the effects of venom, it does not confer lasting immunity, as the recipient's immune system does not develop memory against the venom.