<<–2/”>a href=”https://exam.pscnotes.com/5653-2/”>p>Immunity is the body’s defense mechanism against infectious agents and harmful substances. It involves a complex Network of cells, Tissues, and organs that work together to protect the body. There are two main types of immunity: active and passive. Active immunity occurs when exposure to a disease organism triggers the immune system to produce antibodies to that disease. Passive immunity, on the other hand, is provided when a person is given antibodies to a disease rather than producing them through their own immune system. Understanding the differences, advantages, disadvantages, and similarities between these two types of immunity is essential for comprehending how our bodies defend against pathogens.
| Feature | Active Immunity | Passive Immunity |
|---|---|---|
| Definition | Immunity developed as a result of exposure to an antigen | Immunity acquired by the transfer of antibodies from another individual |
| Source | Generated by the individual’s own immune system | Acquired from an external source (e.g., mother to child, antibody injections) |
| Duration | Long-lasting, often for a lifetime | Short-lived, typically lasting a few weeks to months |
| Onset | Takes time to develop (days to weeks) | Immediate protection |
| Memory | Generates immunological memory | Does not generate immunological memory |
| Examples | Vaccination, natural infection | Maternal antibodies, immunoglobulin therapy |
| Mechanism | Involves activation of B and T lymphocytes | Involves direct administration of antibodies |
| Effectiveness | Highly effective and specific to the pathogen | Immediate but temporary and less specific |
| Booster Requirement | May require boosters to maintain immunity | Does not require boosters |
| Role in Immunotherapy | Used in Vaccines to prevent diseases | Used in immunotherapy for immediate protection against diseases |
| Natural Occurrence | Occurs naturally after recovering from an infection | Occurs naturally when antibodies are transferred from mother to fetus/newborn |
| Artificial Induction | Can be artificially induced via vaccines | Can be artificially induced via antibody injections |
Advantages:
1. Long-lasting protection, often for a lifetime.
2. Generates immunological memory, enabling a quicker and stronger response upon re-exposure.
3. Can be achieved through natural infection or vaccination.
4. Typically specific to the pathogen, providing targeted protection.
Disadvantages:
1. Takes time to develop, leaving a window of vulnerability.
2. May require multiple doses or boosters for full effectiveness.
3. Potential for adverse reactions to vaccines.
4. Not immediately effective in preventing disease during an outbreak.
Advantages:
1. Provides immediate protection, which is crucial in acute or emergency situations.
2. Useful for individuals with weakened immune systems who cannot produce their own antibodies.
3. Can prevent or treat diseases after exposure.
4. Natural passive immunity (maternal antibodies) protects newborns during the early months of life.
Disadvantages:
1. Short-lived protection, requiring repeated doses for sustained immunity.
2. Does not generate immunological memory.
3. Potential for allergic reactions to administered antibodies.
4. Less specific and may not be as effective as active immunity.
Q1: What is the main difference between active and passive immunity?
A1: The main difference is that active immunity involves the body producing its own antibodies in response to an antigen, while passive immunity involves receiving pre-formed antibodies from an external source.
Q2: How long does active immunity last?
A2: Active immunity can last for many years, often a lifetime, especially when memory cells are generated after exposure to the antigen.
Q3: How long does passive immunity last?
A3: Passive immunity is temporary and typically lasts a few weeks to months, as the externally acquired antibodies are eventually broken down and removed from the body.
Q4: Can passive immunity provide immediate protection?
A4: Yes, passive immunity provides immediate protection because it involves the direct administration of antibodies that can immediately neutralize pathogens.
Q5: Do vaccines provide active or passive immunity?
A5: Vaccines provide active immunity by stimulating the body’s immune system to produce its own antibodies and memory cells against specific pathogens.
Q6: Can passive immunity prevent diseases after exposure?
A6: Yes, passive immunity can be used to prevent diseases after exposure, such as administering antibodies after potential exposure to a virus like rabies or hepatitis B.
Q7: Why might someone need passive immunity?
A7: Passive immunity might be needed for individuals who are immunocompromised, have been recently exposed to a pathogen, or need immediate protection against a disease for which they have no immunity.
Q8: What are some natural examples of passive immunity?
A8: Natural examples of passive immunity include the transfer of maternal antibodies to the fetus through the placenta and to the newborn through breast milk.
Q9: Can active immunity be harmful?
A9: While generally safe, active immunity through vaccination can sometimes cause mild to moderate side effects, such as fever, soreness at the injection site, or, in rare cases, more severe reactions.
Q10: Are there any risks associated with passive immunity?
A10: Risks associated with passive immunity include allergic reactions to the antibodies, potential transmission of infections through blood products, and a lack of long-term protection.