Biology In Human Welfare

Human Health and Disease

Active vs Passive Immunity

• Immunity plays a critical role in protecting the human body against pathogens.
• There are two types of immunity: active and passive.
• Let’s understand the difference between active and passive immunity.

Active Immunity:

• Active immunity is the immunity that develops in response to an antigen.
• Antigens are foreign substances that stimulate an immune response.
• Active immunity can be acquired naturally or artificially.

Examples of active immunity:

1. Natural active immunity:

   • Occurs when a person is exposed to a live pathogen and their body produces an immune response.
   • For example, when a person contracts and recovers from a specific disease such as chickenpox, they develop active immunity against it.

2. Artificial active immunity:

   • Induced through vaccination, where a person is administered a vaccine containing a weakened or inactive form of the pathogen.
   • The body recognizes the pathogen as foreign and mounts an immune response, leading to active immunity.

Passive Immunity:

• Passive immunity is the transfer of pre-formed antibodies from one individual to another.
• It provides immediate but temporary protection against a specific pathogen.
• Passive immunity can be acquired naturally or artificially.

Examples of passive immunity:

1. Natural passive immunity:

   • Occurs when a newborn baby receives antibodies from the mother through breast milk or across the placenta.
   • These antibodies provide temporary protection to the baby until their own immune system develops.

2. Artificial passive immunity:

   • Involves the administration of pre-formed antibodies obtained from another individual or an animal.
   • This is commonly used in the treatment of certain diseases or as a preventive measure for high-risk individuals.

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• Both active and passive immunity have their advantages and limitations.
• Active immunity provides long-term protection and allows the body to develop memory cells, leading to a faster and more effective immune response upon subsequent exposure to the same pathogen.
• However, active immunity takes time to develop and may require multiple doses of vaccines.
• Passive immunity, on the other hand, provides immediate but temporary protection without the need for the body to mount an immune response.
• However, passive immunity does not lead to the development of memory cells, and the protection diminishes over time.

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Importance of Active Immunity

• Active immunity plays a crucial role in preventing infectious diseases.
• Vaccines are the most common way to induce active immunity.
• Vaccination programs have made a significant impact on global health by preventing the spread of diseases like polio, measles, and influenza.
• By developing active immunity, individuals not only protect themselves but also contribute to herd immunity, reducing the overall prevalence of the disease in the population.

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Importance of Passive Immunity

• Passive immunity is particularly important for individuals who are at immediate risk of a specific disease or have compromised immune systems.
• It provides them with quick protection before their own immune system can respond effectively.
• For example, passive immunization with antibodies against the rabies virus is given to individuals who have been exposed to the virus.
• Passive immunity also plays a role in protecting newborn babies during the early months of their life.

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Limitations of Active Immunity

• Active immunity takes time to develop as the immune system needs to recognize and mount a response against the pathogen.
• It may require multiple doses of vaccines to achieve optimal immunity.
• Certain individuals, such as those with compromised immune systems, may not develop a strong immune response even after vaccination.

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Limitations of Passive Immunity

• Passive immunity provides only temporary protection as the transferred antibodies gradually degrade and disappear from the body.
• It does not lead to the development of memory cells and subsequent immune responses upon future exposure.
• Passive immunization may sometimes trigger allergic reactions or other adverse effects, particularly if the antibodies are derived from non-human sources.

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Combination Approaches

• In some cases, a combination of both active and passive immunity may be used for maximum protection.
• For example, individuals may receive a vaccine for active immunity followed by a boost of pre-formed antibodies for immediate protection.
• This approach is often used in the prevention and treatment of certain viral infections, such as hepatitis and varicella-zoster.
• Researchers continue to explore innovative strategies to enhance immune responses and develop more effective immunotherapies.

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Conclusion

• Active and passive immunity are two essential components of the immune system’s defense against pathogens.
• Active immunity is induced by exposure to antigens or vaccines, leading to the development of long-lasting protection and memory cells.
• Passive immunity involves the transfer of pre-formed antibodies, providing immediate but temporary protection.
• Both types of immunity have their advantages and limitations, and their applications depend on the specific circumstances and needs of individuals.
• Ongoing research in immunology continues to advance our understanding of these immune mechanisms and improve strategies for disease prevention and treatment.

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Revision Questions

1. What is the difference between active and passive immunity?
2. Give examples of natural active immunity and artificial active immunity.
3. Explain the concept of passive immunity with suitable examples.
4. What are the advantages of active immunity? Give an example.
5. What are the limitations of passive immunity? Provide reasons.
6. How can a combination of active and passive immunity be used for maximum protection?
7. What role do vaccines play in active immunity?
8. How does active immunity contribute to herd immunity?
9. Why is passive immunity important for newborn babies?
10. What is the significance of ongoing research in immunology?

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Further Reading and References

• “Understanding Vaccines: What They Are, How They Work”, World Health Organization (WHO)
• “Passive Immunization”, Immunization Action Coalition (IAC)
• “Development of Immunotherapies in Modern Medicine”, Journal of Clinical Medicine
• “Advances in Immunology: Nonlinguistical Frontier”, National Institutes of Health (NIH)

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Thank You!

• Feel free to ask any questions or discuss any related topics.
• Stay curious and keep exploring the fascinating world of biology!

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Immune System Disorders

• The immune system is designed to protect the body from harmful substances.
• However, sometimes the immune system malfunctions, leading to immune system disorders.
• Immune system disorders can be classified into two broad categories: hypersensitivity and autoimmune disorders.

Hypersensitivity Disorders:

• Hypersensitivity disorders occur when the immune system overreacts to harmless substances.
• There are four types of hypersensitivity reactions:
  1. Type I: Immediate hypersensitivity, e.g., allergies to pollen or peanuts.
  2. Type II: Antibody-mediated hypersensitivity, e.g., transfusion reactions or autoimmune hemolytic anemia.
  3. Type III: Immune complex-mediated hypersensitivity, e.g., rheumatoid arthritis or systemic lupus erythematosus.
  4. Type IV: Cell-mediated hypersensitivity, e.g., contact dermatitis or organ transplant rejection.

Autoimmune Disorders:

• Autoimmune disorders occur when the immune system mistakenly attacks the body’s own cells and tissues.
• Examples of autoimmune disorders include rheumatoid arthritis, systemic lupus erythematosus, multiple sclerosis, and Type 1 diabetes.
• These disorders are characterized by chronic inflammation and varying degrees of organ damage.

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Cancer and the Immune System

• Cancer occurs when the body’s cells undergo uncontrolled growth and division.
• The immune system plays a crucial role in recognizing and eliminating cancer cells.
• However, cancer cells can sometimes evade or suppress the immune response, leading to the progression of the disease.

Cancer Immunotherapy:

• Cancer immunotherapy is an emerging field that uses the body’s immune system to fight cancer.
• There are several approaches to cancer immunotherapy, including:
  1. Immune checkpoint inhibitors: These drugs release the ‘brakes’ on the immune system, allowing it to attack cancer cells more effectively.
  2. CAR-T cell therapy: This therapy involves modifying a patient’s T cells to express chimeric antigen receptors (CARs) that recognize specific cancer cells.
  3. Cancer vaccines: These vaccines stimulate the immune system to recognize and attack specific cancer cells.

Examples of Cancer Immunotherapy:

• Pembrolizumab (Keytruda) and Nivolumab (Opdivo) are immune checkpoint inhibitors used in the treatment of various types of cancer.
• Kymriah and Yescarta are CAR-T cell therapies approved for certain types of lymphomas and leukemias.

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Immunodeficiency Disorders

• Immunodeficiency disorders occur when the immune system is weakened or fails to function properly.
• These disorders can be primary, resulting from genetic defects, or secondary, resulting from other conditions or treatments.

Primary Immunodeficiency Disorders:

• Primary immunodeficiencies are usually genetic and present from birth.
• Examples include severe combined immunodeficiency (SCID), X-linked agammaglobulinemia, and common variable immunodeficiency (CVID).
• These disorders impair the immune system’s ability to fight infections, making affected individuals more susceptible to recurrent and severe infections.

Secondary Immunodeficiency Disorders:

• Secondary immunodeficiencies are acquired and can develop due to various factors, including:
  • Certain infections, such as HIV/AIDS
  • Malnutrition
  • Chronic illnesses, like diabetes or kidney disease
  • Immunosuppressive therapies, such as chemotherapy or long-term steroid use

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Immunotherapy in Infectious Diseases

• Immunotherapy can also be used in the treatment of infectious diseases.
• It involves enhancing or modulating the immune system’s response to combat the infectious agent.

Examples of Immunotherapy in Infectious Diseases:

1. Monoclonal antibodies: These antibodies are designed to target specific pathogens, such as viruses or bacteria, and neutralize their activity.
2. Interferons: These proteins help in the defense against viral infections by inhibiting viral replication and enhancing the immune response.
3. Passive immunization: In certain cases, preformed antibodies against specific infectious agents are administered to provide immediate protection while the body’s immune system responds.

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Conclusion

• The immune system plays a crucial role in maintaining health and protecting the body from various diseases.
• Immune system disorders can lead to hypersensitivity reactions, autoimmune disorders, or immunodeficiency disorders.
• Cancer immunotherapy aims to enhance the immune system’s ability to recognize and destroy cancer cells.
• Immunotherapy can also be used in the treatment of infectious diseases.
• Continued research and advancements in immunology hold promise for the development of novel immune-based therapies.

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Revision Questions

1. Name the four types of hypersensitivity reactions.
2. Give examples of autoimmune disorders.
3. How does cancer immunotherapy work?
4. Name two immune checkpoint inhibitors used in cancer treatment.
5. Differentiate between primary and secondary immunodeficiency disorders.
6. What are the potential causes of secondary immunodeficiency disorders?
7. How can immunotherapy be used in the treatment of infectious diseases?
8. Name a type of immunoglobulin used in passive immunization.
9. Explain the concept of immune checkpoint inhibitors.
10. What is the role of interferons in combating viral infections?

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Further Reading and References

• “Immunotherapy in Cancer: Unleashing the Immune Response against Cancer”, National Cancer Institute (NCI)
• “Understanding Autoimmune Diseases”, American Autoimmune Related Diseases Association (AARDA)
• “Primary Immunodeficiency Diseases: A Molecular and Genetic Approach”, National Center for Biotechnology Information (NCBI)
• “Immunotherapy in Infectious Diseases: A Review”, Frontiers in Immunology journal

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Additional Resources

• “The Immune System: A Very Short Introduction” by Paul Klenerman.
• “Immunology: An Illustrated Outline” by David Male.
• Online resources and journals:
  • Nature Immunology
  • Journal of Immunology
  • Cell Reports Immunology

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Tips for Exam Preparation

• Review and understand the different types of immune system disorders.
• Familiarize yourself with the mechanisms and examples of cancer immunotherapy.
• Study the characteristics and causes of primary and secondary immunodeficiency disorders.
• Stay updated with the latest developments in immunotherapy for infectious diseases.
• Practice answering questions related to immune system disorders and immunotherapy.
• Utilize additional resources, such as books and online materials, for in-depth understanding.

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Thank You!

• If you have any questions or need further clarification, feel free to ask.
• Good luck with your exam preparation!
• Keep studying and exploring the fascinating field of biology!