Immune System Overview

Immune System

• Body’s defense mechanism against invasion by foreign substances, allowing a rapid response to foreign substances
• Composed of various cell types including mucous membranes, lymphatic vessels, tonsils, thymus, lymph nodes, and skin
• Bone marrow is the primary site of blood cell production (hematopoiesis) in birds and mammals
• Spleen stores and filters blood, making blood cells that protect against infection
• Factors influencing immune function include central nervous system integrity, physical and emotional status, medications, dietary patterns, and stress

Immune Memory

• Property of the immune system that provides protection against harmful microbial agents despite the timing of re-exposure

Tolerance

• Immune system is programmed to eliminate foreign substances, but maintains the ability to accept self-antigens.
• Examples include microbes, toxins, and cellular mutations

Surveillance

• Immune system is in a perpetual state of vigilance, screening and rejecting any invader that is recognized as foreign to the host.

Immune System Disorders

• Autoimmunity: Normal protective immune response paradoxically turns against or attacks the body, leading to tissue damage. The body’s immune system mistakenly attacks its own healthy tissues and cells due to perceiving them as harmful.
  • Examples: Type I Diabetes, Rheumatoid Arthritis, Multiple sclerosis, SLE
• Hypersensitivity: Body produces inappropriate or exaggerated responses to specific antigens. Typically refers to hypersensitivity reactions, which are excessive immune responses that can cause tissue damage and result in various allergic or immune-related conditions, including Type I (IgE antibodies), Type II (cytotoxic IgG IgM antibodies), Type III (immune complexes), and Type IV (delayed reaction by cellular response).
• Immunodeficiencies: Primary (genetic) or secondary (acquired) leading to increased susceptibility to infections.
• Gammopathies: Overproduction of immunoglobulins. Refers to excessive levels of antibody globulins in the blood.

Immune System Responses

• Natural Immunity: Present at birth, non-specific defense against pathogens, involving cells like macrophages and neutrophils
• Acquired Immunity: Develops after exposure to pathogens or vaccinations
  • Active Immunity: Developed by the body (long-lasting)
    • Natural (chicken pox, measles)
    • Artificial (hepa b vaccine, tetanus toxoid vaccine)
  • Passive Immunity: Transferred from another source (temporary)
    • Natural
    • Artificial (Immunoglobulins. Post-exposure prophylaxis, serotherapy)

Immune Cell Types

• B Lymphocytes (B Cells): Produce antibodies and are involved in humoral immunity.
• T Lymphocytes (T Cells): Participate in cellular immunity.
  • Helper T Cells: Assist in immune responses by activating other immune cells.
  • Cytotoxic T Cells: Destroy infected cells or cancerous cells.
  • Natural Killer Cells: Kill cells that lack MHC class I molecules, which are often cancerous cells.

Cancer & Immunotherapy

• Cancer: Recent advancements aim to enhance the immune system’s ability to combat cancer.
• Immunotherapy: A type of cancer treatment that helps your immune system fight cancer.
  • Immunotherapeutic strategies:
    • Monoclonal antibodies (MoAbs)
    • Cancer vaccines
    • Immune checkpoint inhibitors
    • CAR T-cell therapy

Immunomodulators

• Also known as “biologic response modifier”
• Treatments that modify the immune response, such as interferons, colony-stimulating factors, and monoclonal antibodies, are used to enhance immune function in various diseases.

Interferons

• Natural substance that helps the body’s immune system fight infection and other diseases, such as cancer.
• Made in the body (white blood cells and other cells) and the laboratory.
• Four types:
  • Interferon-alpha (alfa)
  • Interferon-beta
  • Interferon-gamma
  • Interferon-lambda

Colony-stimulating Factors

• Proteins that help control the production and growth of blood cells in the body.
• Play a role in making sure these cells develop properly, survive, and become active when needed.
• Examples:
  • Interkulin 5
  • Stem cell factor
  • GCSF

Monoclonal Antibodies

• Also known as moAbds or mAbs
• Proteins made in laboratories that act like proteins called antibodies in our bodies.
• They seek out the antigens (foreign materials) and stick to them to destroy them.
• Laboratory-made monoclonal antibodies help stimulate our immune system.

Assessment of Immune Function

• Health history and physical examination
• Blood tests
• Bone Marrow biopsy
• Skin tests

Factors Affecting Immune Function

• Infection
• Allergy
• Disorders and diseases
• Gender differences
• Aging (immunosenescence)
• Immunization
• Psychoneuroimmunology

Nursing Implications

• Nurses should assess and monitor for signs of immune dysfunction, ensuring prompt intervention and management.

Primary Immune Deficiency

• Born with a weak immune system
• Rare genetic disorders that impair the immune system.
• Examples: IgA deficiency, common variable immunodeficiency (CIV), and severe combined immunodeficiency disease (SCID), also known as “bubble boy disease”

Secondary Immune Deficiency

• Immune system is compromised due to an environmental factor.
• Examples: Chemotherapy, radiation therapy (RT), chronic disease, burns, HIV, and leukemia.

Acquired Immune Deficiency

• Get a disease that weakens the immune system.
• Disease of the immune system caused by the Human Immunodeficiency Virus (HIV).
• Targets the body’s white blood cells, weakening the immune system.

Explore the intricate workings of the immune system, examining its mechanisms for defending against foreign invaders. This quiz covers components such as immune memory, tolerance, and surveillance, highlighting the factors that influence immune function. Test your knowledge on how the body maintains its health against infections and diseases.