Biology In Human Welfare

Human Health and Disease

Immunity

• Introduction to Immunity

  • Immunity is the ability of an organism to resist foreign substances, infections, and diseases.
  • It is an important defense mechanism that protects our body from harmful pathogens.
  • Immunity can be acquired naturally or artificially.

• Types of Immunity

  • Innate Immunity
    • Present at birth
    • Non-specific response to foreign substances
    • Examples: Skin, mucus, tears, etc.
  • Adaptive Immunity
    • Acquired after birth
    • Specific response to particular pathogens
    • Examples: Antibodies, T cells, B cells, etc.

• Components of Immune System

  • Lymphatic System
  • White Blood Cells (WBCs)
    • Neutrophils
    • Eosinophils
    • Basophils
    • Lymphocytes
      • T cells
      • B cells
      • Natural Killer (NK) cells

• Humoral Immune Response

  • Mediated by B cells
  • Produces antibodies in response to antigens
  • Antibodies neutralize or eliminate antigens
  • Example: Production of antibodies against bacteria

• Cell-Mediated Immune Response

  • Mediated by T cells
  • Helps in destroying infected cells
  • Enhances immune response
  • Example: Killing of virus-infected cells

• Antigens and Antibodies

  • Antigens are foreign substances that trigger an immune response.
  • Antibodies, also known as immunoglobulins, are proteins produced by B cells in response to antigens.
  • Antibodies bind to antigens and help in their elimination.

• Major Histocompatibility Complex (MHC)

  • MHC is a group of genes that code for cell surface proteins important for immune recognition.
  • MHC proteins help in presenting antigens to T cells for recognition and activation of immune response.
  • MHC is classified into two types: MHC-I and MHC-II.

• Types of Immunity - Active and Passive

  • Active Immunity
    • Developed by the body’s immune system
    • Induced by exposure to pathogens or vaccines
    • Long-lasting protection
  • Passive Immunity
    • Transferred from one individual to another
    • Temporary protection
    • Example: Maternal antibodies transferred to the fetus

• Vaccination and Immunization

  • Vaccination is the process of introducing weakened or killed pathogens into the body to stimulate an immune response.
  • Immunization is the development of immunity against a specific pathogen through vaccination.
  • Vaccination helps in preventing the occurrence of diseases.

• Disorders of the Immune System

  • Autoimmune Diseases
    • Immune system attacks self-cells and tissues
    • Examples: Rheumatoid arthritis, Multiple sclerosis
  • Immunodeficiency Disorders
    • Weakened or absent immune response
    • Examples: HIV/AIDS, Severe Combined Immunodeficiency (SCID)
  • Hypersensitivity Reactions
    • Abnormal immune response to harmless substances
    • Examples: Allergies, Asthma

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• Viral Infections
  • Viruses are intracellular pathogens that can cause various diseases.
  • Examples: Influenza, HIV, Hepatitis, COVID-19.
  • Viral infections can be prevented by vaccination and practicing good hygiene.

• Bacterial Infections
  • Bacteria are single-celled microorganisms that can cause infections.
  • Examples: Tuberculosis, Cholera, Pneumonia.
  • Antibiotics are commonly used to treat bacterial infections.

• Fungal Infections
  • Fungi are eukaryotic microorganisms that can cause infections.
  • Examples: Candidiasis, Athlete’s foot, Ringworm.
  • Antifungal medications are used to treat fungal infections.

• Parasitic Infections
  • Parasites are organisms that live on or in another organism and obtain nutrients from it.
  • Examples: Malaria, Amoebiasis, Giardiasis.
  • Antiparasitic medications are used to treat parasitic infections.

• Allergies
  • Allergies occur when the immune system overreacts to harmless substances (allergens).
  • Common allergens include pollen, dust mites, pet dander, and certain foods.
  • Allergic reactions can range from mild (sneezing, itching) to severe (anaphylaxis).

• Autoimmune Diseases
  • Autoimmune diseases occur when the immune system mistakenly attacks the body’s own cells and tissues.
  • Examples: Rheumatoid arthritis, Lupus, Type 1 Diabetes.
  • The exact cause of autoimmune diseases is unknown, but genetic and environmental factors play a role.

• Immunodeficiency Disorders
  • Immunodeficiency disorders are characterized by a weakened or absent immune response.
  • Primary immunodeficiency disorders are inherited, while secondary immunodeficiency disorders can be acquired.
  • Examples: HIV/AIDS, SCID, DiGeorge syndrome.

• Cancer and Immune System
  • Cancer occurs when abnormal cells divide and spread uncontrollably.
  • The immune system plays a crucial role in recognizing and eliminating cancer cells.
  • Immunotherapy is a type of cancer treatment that enhances the immune system’s ability to fight cancer.

• Organ Transplantation and Immune Response
  • Organ transplantation involves replacing a diseased organ with a healthy one from a donor.
  • The immune system can recognize the transplanted organ as foreign and mount an immune response.
  • Immunosuppressive drugs are used to prevent rejection and maintain organ function.

• HIV/AIDS
  • HIV (Human Immunodeficiency Virus) is a retrovirus that attacks the immune system, specifically CD4+ T cells.
  • AIDS (Acquired Immunodeficiency Syndrome) is the advanced stage of HIV infection.
  • HIV is transmitted through unprotected sexual contact, sharing needles, or mother-to-child during childbirth or breastfeeding.

• Influenza
  • Also known as the flu, caused by the influenza virus.
  • Symptoms include fever, cough, sore throat, muscle aches, and fatigue.
  • Influenza can be prevented by yearly vaccinations.
  • Vaccination is recommended for high-risk individuals such as the elderly and those with chronic illnesses.
  • Antiviral drugs can be used for treatment.

• Tuberculosis (TB)
  • Caused by Mycobacterium tuberculosis bacteria.
  • Primarily affects the lungs but can also affect other organs.
  • Symptoms include cough, chest pain, fatigue, weight loss, and night sweats.
  • TB can be treated with a combination of antibiotics for several months.
  • BCG vaccine is available for prevention, but its effectiveness varies.

• Malaria
  • Caused by Plasmodium parasites transmitted by infected mosquitoes.
  • Symptoms include fever, chills, headache, and muscle aches.
  • Anti-malarial drugs can be used for treatment and prevention.
  • Prevention includes the use of bed nets, insect repellents, and elimination of mosquito breeding sites.
  • Malaria is a major health problem in tropical and subtropical regions.

• Hepatitis
  • Inflammation of the liver, usually caused by viruses (Hepatitis A, B, C, D, and E).
  • Symptoms include fatigue, jaundice, abdominal pain, and loss of appetite.
  • Hepatitis A and B vaccines are available for prevention.
  • Treatment depends on the type of hepatitis, ranging from supportive care to antiviral medications.
  • Chronic hepatitis can lead to liver cirrhosis or cancer.

• HIV/AIDS
  • Human Immunodeficiency Virus (HIV) attacks the immune system, leading to Acquired Immunodeficiency Syndrome (AIDS).
  • HIV is primarily transmitted through unprotected sexual contact, sharing needles, or mother-to-child during childbirth or breastfeeding.
  • Symptoms include fever, weight loss, fatigue, night sweats, and opportunistic infections.
  • Antiretroviral therapy (ART) can suppress the virus, extending the life expectancy of individuals with HIV/AIDS.
  • Prevention focuses on safe practices, including condom use, needle exchange programs, and HIV testing.

• Allergy Management
  • Allergies can be managed by avoiding allergens and taking medications.
  • Antihistamines can help relieve allergy symptoms such as sneezing, itching, and runny nose.
  • Corticosteroids can control inflammation in severe allergic reactions.
  • Allergen immunotherapy, such as allergy shots, can desensitize the immune system to specific allergens.
  • Education about allergies and proper management is essential to reduce allergic reactions.

• Rheumatoid Arthritis
  • Autoimmune disease that causes chronic inflammation and joint pain.
  • Immune system attacks the synovium, a tissue lining the joints.
  • Symptoms include joint stiffness, swelling, and deformities.
  • Treatment includes medication to reduce inflammation and pain, physical therapy, and joint replacement surgery if necessary.
  • Early diagnosis and treatment can help manage the symptoms and prevent joint damage.

• Cancer Immunotherapy
  • Cancer immunotherapy uses the immune system to fight cancer cells.
  • Examples include immune checkpoint inhibitors, CAR-T cell therapy, and cancer vaccines.
  • Immune checkpoint inhibitors block proteins that prevent immune cells from attacking cancer cells.
  • CAR-T cell therapy involves modifying a patient’s T cells to recognize and kill cancer cells.
  • Cancer vaccines stimulate the immune system to recognize and destroy cancer cells.

• Biological Therapies
  • Biological therapies use substances derived from living organisms to treat diseases.
  • Examples include monoclonal antibodies, recombinant proteins, and gene therapies.
  • Monoclonal antibodies can specifically target cancer cells or immune cells involved in autoimmune diseases.
  • Recombinant proteins are synthetic versions of naturally occurring proteins used for various therapeutic purposes.
  • Gene therapies involve introducing or modifying genes to treat genetic disorders or cancer.

• Ethics in Biotechnology and Medicine
  • Biotechnology and medicine raise ethical concerns related to genetic engineering, stem cell research, and human cloning.
  • Ethical considerations include the balance between scientific advancements and potential risks, informed consent, and equitable access to healthcare.
  • Regulatory bodies and guidelines help ensure ethical practices in biotechnology and medicine.
  • Debates and discussions are ongoing to address ethical dilemmas and establish ethical frameworks in these fields.
  • Education and awareness about ethical issues are crucial for healthcare professionals and the general public.