Immunology

• Immunology is the study of a host’s reactions when foreign substances are introduced into the body.
• Immunity is the condition of being resistant to infection.
• Antigens are a foreign substance that induces an immune response.
• Antibodies confer immunity by neutralizing antigens.
• Syphilis is an infectious disorder caused by a spirochete, Treponema pallidum, usually transmitted in humans by sexual contact.
• Streptococcal infections can result in post-streptococcal sequelae such as Glomerulonephritis.
• Streptococcal infections are caused by Streptococcus pyogenes.
• The body’s three main lines of defense are the First Line of Defense, the Second Line of Defense (Natural Immunity), and the Third Line of Defense (Adaptive Immunity).
• The First Line of Defense is composed chiefly of external physical barriers to pathogens, especially the skin and mucous membranes.
• The Second Line of Defense (Natural Immunity) is composed of protective cells, blood, borne chemicals, and processes that inactivate or kill invaders.
• The Third Line of Defense (Adaptive Immunity) is composed of cellular and humoral components which are lymphocytes and antibodies.
• Innate Immunity is natural, non-specific, and the same for all pathogens.
• Adaptive Immunity is acquired, specific, and unique for each pathogen.
• Innate Immunity provides the first line of defense and is the primary defense.
• Adaptive Immunity provides the second line of defense and is the secondary defense.
• Anamnestic: ability to remember a prior exposure.
• Monocytes, the largest cells in the peripheral blood, migrate to tissues and become Macrophages, which are antigen-presenting cells.
• All macrophages arise from Monocytes, with Alveolar Macrophages in the Lungs, Kuppfer cells in the Liver, Microglial cells in the Brain, and Histiocytes in Connective Tissues.
• Antibodies are disease-fighting proteins in the body that play a crucial role in the immune system, developing during an infection or in response to a vaccine.
• Each antibody is specific and has one of two precise tasks: tag an invader for destruction by other immune cells or destroy the invader by itself.
• Basophils function to induce and maintain immediate hypersensitivity reaction and contain Histamine, a vasoactive amine that contracts smooth muscle, and Heparin, an anticoagulant.
• Antigens are substances that stimulate antibody formation and immunogen is another term for antigen.
• Eosinophils increase in allergic response to parasitic infection and neutralize basophil and mast cell products killing certain parasites.
• Neutrophils, also known as Polymorphonuclear Neutrophilic (PMN) leukocytes, increase on Acute Infection and are the first responders, capable of Phagocytosis, Diapedesis, and Chemotaxis.
• Antibodies (Immunoglobulins/Gamma Globulins) include IgG, IgA, IgM, IgD, IgE.

  
  

  IgG being a secondary response antibody, providing protection for newborn

  IgA found in tears, saliva, colostrum, milk and intestinal fluids,

  IgE playing a role in allergic reactions and defends parasitic infections.

  IgM the primary response antibody; effective in agglutination and cytolytic reactions.

  IgD produced by B-cells; postulated as anti-idiopathic antibody
• Phagocytosis is the purpose of Inflammatory Reactions to localize infection, prevent spread of microbial invaders, neutralize toxins, and aid in the repair of damaged tissues.
• Antigens can be foreign, degradable, of a certain molecular weight, structurally stable, complex, or a combination of these factors.
• B-Lymphocytes secrete Immunoglobulin and develop in the bone marrow in adults.
• Patients with Systemic Lupus Erythematosus exhibit multiple serum antibodies that react with native or altered self antigens.
• Lymphocytes are cells derived from the bone marrow.
• Autoimmune diseases result when a person’s immune system no longer recognizes certain body tissues as self and attempts to destroy those tissues as if they were non-self or foreign.
• T-helper cells are a type of T-lymphocyte responsible for cell-mediated immune response.
• Examples of autoimmune diseases include Type 1 Diabetes, Multiple Sclerosis, Rheumatoid arthritis, and SLE.
• Signs and symptoms of Systemic Lupus Erythematosus include Alopecia, Butterfly-rash syndrome, Raynaud’s phenomenon, fever, Lymphadenopathy.
• Immunodeficiencies can be acquired or inherited and examples include Chronic Granulomatous Disease and Di-George Syndrome.
• Systemic Lupus Erythematosus is a disease of acute and chronic inflammation with circulating immune complexes as the hallmark.
• Immunologic disorders include Systemic Lupus Erythematosus and Rheumatoid Arthritis.
• Rheumatoid Arthritis is a chronic, usually progressive, inflammatory disorder of the joints, ranging from mild illness to a progressive, destructive polyarthritis associated with a systemic vasculitis.