NR 283 Chapter 7 Immunity
What happens during the first stage of AIDS?
- a few weeks after exposure, viral replication is rapid and there may be mild, generalized flulike symptoms such as low fever, fatigue, arthralgia, and sore throat. (goes away w/o treatment)
What are cytotoxic T cells?
- destroy the target cell by binding to the antigen and releasing damaging enzymes or chemicals, such as monokines and lymphokines, which may destroy foreign cell membranes or cause an inflammatory response, attract macrophages to the site, stimulate the proliferation of more lymphocytes, and stimulate hematopoiesis.
What are the lymphoid structures?
- Lymph nodes - Spleen - Tonsils - Intestinal lymphoid tissue - Lymphatic circulation -These form the basic structure within which the immune response can function
What are the generalized effects of AIDS?
- Lymphadenopathy - fatigue and weakness - headache, - Arthralgia - Gastrointestinal effects seem to be related primarily to opportunistic infections, including parasitic infections - chronic severe diarrhea, vomiting, and ulcers on the mucous membranes.
What happens during the prolonged period or latent stage of AIDS?
- Lymphadenophathy (swelling of lymph nodes)
What is HIV-1 ?
- Major cause of AIDS in US and Europe
What is HIV-2?
- Major cause of AIDS in central Africa
What does the Titer diagnostic test do?
- Measures levels of serum immunoglobulins - Measure of specific antibodies
What is the retrovirus?
- Member of the subfamily, lentivirus - Contains RNA - Infection develops slowly
What is the IgG antibody?
- Most common in blood - produced in both primary and secondary immune responses - activates complement - includes antibacterial, antiviral, and antitoxin antibodies; crosses placenta - creates passive immunity in newborn
What is Active Natural Immunity?
- Natural exposure to antigen - Development of antibodies EXAMPLE: - when a person has an infection and then develops antibodies.
What is emerging infectious disease?
- Newly identified in a population
What is chronic, late rejection?
- Occurs after months or years - Gradual degeneration of blood vessels
What diagnostic tests can be done to test for AIDS?
- Presence of HIV infection by doing blood test for HIV antibodies - Three stage process 1. Presence of HIV ½ antigen/antibody 2. Differentiation/identification between HIV-1 and HIV-2 antibodies 3. A nucleic acid test is used
What is re-emerging infectious disease?
- Previously under control • No consistence in vaccination programs • On rise due to globalization, drug resistance, and other factors - Example: measles in the United States
What is immunosuppression?
- Reduction of immune response to prevent rejection -Commonly used drugs Ø Cyclosporine, azathioprine, prednisone - High risk of infection Ø Caused by immunosuppression Ø Opportunistic organisms
What is Secondary response in the immune system?
- Repeat exposure to the same antigen - More rapid response, with efficacy in 1 to 3 days - Even years later the memory cells quickly stimulate production of large numbers of the matching antibodies or T cells.
What is the treatment for Anaphylaxis?
- Requires first aid response - Administer EpiPen if available. - Call 9-1-1 (many paramedics can start drug treatment and oxygen) - Treatment in emergency department - Epinephrin's - Glucocorticoids (may be used for severe or pro- longed reactions because they reduce the immune response and stabilize the vascular system.) - Antihistamines (Benadryl) are useful in the early stages of an allergic reaction because they block the response of the tissues to the released histamine (blocking histamine-1 receptors on cells). - Oxygen - Stabilize BP
What is the immune system? And what are the two responses?
- Responsible for body defenses Nonspecific response (defense) • Examples: phagocytosis, inflammation Specific response (defense) • Production of specific antibodies against foreign substances • Is responding to specific substances, cells, toxins, or proteins which are perceived as foreign substances to the body and are unwanted and potentially dangerous • The specific immune response is intended to recognize and remove undesirable material from cells, tissues, and organs.
What are B lymphocytes?
- Responsible for production of antibodies - After exposure to antigens, and with the assistance of T lymphocytes, they become antibody-producing plasma cells - B lymphocytes act primarily against bacteria and viruses that are outside body cells. • Humoral immunity • Mature in bone marrow Proceed to spleen and lymphoid tissue
What diagnostic tests can be done to test for Systemic Lupus Erythematosus (SLE)?
- Serum antibodies, LE cells, other blood work - Prescence of numerous auto antibodies, especially anti-DNA - Complement levels are low and erytho sedimentation rate is high
When should treatment start for AIDS?
- Severe symptoms - CD4 count is under 500 - Pregnancy - HIV-related kidney disease - When one is being treated for hepatitis B
What is Natural Immunity?
- Species-specific - Meaning humans are not usually susceptible to infections common to many other animals.
What are the signs and symptoms of an allergic reaction?
- The signs and symptoms of an allergic reaction occur on the second or any subsequent exposure to the specific allergen because the first exposure to the allergen causes only the formation of antibodies and sensitized mast cells. - The target area becomes red and swollen, there may be vesicles or blisters present, and usually the area is highly pruritic or itchy
Why is the thymus significant during fetal development?
- The thymus is significant during fetal development in that it programs the immune system to ignore self-antigens.
What does the MHC typing diagnostic test do?
- Tissue matching before transplantation procedures
What is the treatment for Systemic Lupus Erythematosus (SLE)?
- Usually treated by a rheumatologist. - Prednisone (glucocorticoid) - Nonsteroidal anti-inflammatory drugs
What is Type I hypersensitivity reaction?
- allergic reactions - IgE mediated. mast and basophils release histamine - A tendency toward allergic conditions is inherited, and the manifestation of such an allergy in a family is referred to as an atopic hypersensitivity reaction
What is the causative mechanism of allergies?
- begins when an individual is exposed to a specific allergen and for some reason develops IgE antibodies from B lymphocytes. - These antibodies attach to mast cells in specific locations, creating sensitized mast cells. - Mast cells are connective tissue cells that are present in large numbers in the mucosa of the respiratory and digestive tracts - On re exposure to the same allergen, the allergen attaches to the IgE antibody on the mast cell, stimulating the release of chemical mediators such as histamine from granules within the mast cells - These chemical mediators cause an inflammatory reaction involving vasodilation and increased capillary permeability at the site (eg, the nasal mucosa), resulting in swelling and redness of the tissues. - This initial release of histamine also irritates the nerve endings, causing itching or mild pain. - If the sensitized mast cells are located in the respiratory tract or mucous membrane it causes hay fever or vasoconstriction
What are helper T cells?
- facilitates the immune response
What is Acquired Immunodeficiency Syndrome (AIDS)?
- AIDS—chronic infectious disease caused by the human immunodeficiency virus (HIV) - HIV destroys helper T cells—CD4 lymphocytes. - Loss of immune response Increased susceptibility to secondary infections and cancer - Prolonged latent period - Development may be suppressed by antivirals. - At an early stage, the virus invades and multiplies in lymphoid tissue, the lymph nodes, tonsils, and spleen, using these tissues as a reservoir for continued infection. - HIV attacks macrophages and central nervous system cells.
What is IgE antibody?
- Allergic response - Causes release of histamine and other chemicals - Results in inflammation - Binds to mast cells in skin and mucous membranes; when linked to Allergen
What is type 3 hypersensitivity?
- Also known as Immune Complex Hypersensitivity - Antigen combines with antibody Forms immune complexes, deposited in tissue often in blood vessel walls, and also activates complement - Activation of complement system - Process causes inflammation and tissue destruction EXAMPLE: - Glomerulonephritis - Rheumatoid arthritis
What is type 2 hypersensitivity?
- Also known as cytotoxic hypersensitivity - Antigen is present on cell membrane - May be normal body component or exogenous (foreign) - Circulating IgGs react with antigen causing Destruction by phagocytosis or cytolytic enzymes that activate complement system EXAMPLE: - HAPPENS DURING AN INCOMPATIBLE BLOOD TRANSFUSION
What is Active Artificial Immunity?
- Antigen purposefully introduced to body - Stimulation of antibody production - Immunization EXAMPLE: - a vaccine is a solution containing dead or weakened (attenuated) organisms that stimulate the immune system to produce antibodies but does not result in the disease itself.
What is the treatment for AIDS?
- Antiviral drugs can reduce the replication of viruses, but they do not kill the virus, and thus are not a cure. - Non-nucleoside reverse transcriptase inhibitors (NNRTIs) - Nucleoside reverse transcriptase inhibitors (NRTIs) - Protease inhibitors (PIs) - Fusion inhibitors - CCR5 antagonists (CCR5s) (entry inhibitors) - Integrase strand transfer inhibitors (INSTIs) - Azidothymidine (AZT) is probably the best-known single drug being used in the fight against HIV; however, combinations of three to five drugs in a "cocktail" are being used successfully to prolong the latent phase as well as reduce the viral load during the final phase
What is the IgD antibody?
- Attached to B cells - Activates B cells
Explain The auto immune process?
- Autoimmune disorders occur when individuals develop antibodies to their own cells or cellular material, and these antibodies then attack the individual's tissues - The term autoantibodies refers to antibodies formed against self-antigens. - Self-antigens are usually tolerated by the immune system, and there is no reaction to one's own antigens. - When self-tolerance is lost, the immune system is unable to differentiate self from foreign material. The autoantibodies then trigger an immune reaction leading to inflammation and necrosis of tissue.
What are Autoimmune disorders?
- Autoimmune disorders occur when the immune system cannot distinguish between self and nonself antigens. - Development of antibodies against own cells or tissues - Autoantibodies are antibodies formed against self-antigens—loss of self-tolerance. - Disorder can affect single organs or tissues or can be generalized. EXAMPLES: Hashimoto thyroiditis, systemic lupus erythematosus, rheumatic fever, myasthenia gravis, scleroderma, pernicious anemia
What are the primary deficincies of Immunodeficiency?
- Basic developmental failure somewhere in the system - in the bone marrow's production of stem cells, the thymus, or the synthesis of antibodies. - Many defects result from a genetic or congenital abnormality and are first noticed in infants and children.
How is AIDS transmitted?
- Bodily fluids - Blood - Semen - Vaginal fluids
What is the IgM antibody?
- Bound to B lymphocytes in circulation and is usually the first to increase in the immune response - activates complement - Forms natural antibodies - is involved in blood ABO type incompatibility reaction
What are macrophages?
- CRITICAL in the Initiation of immune response - Develop from monocytes - Part of the mononuclear phagocytotic system - Engulf foreign material and Display antigens of foreign material on their cell membrane, the lymphocytes respond to this display, thus initiating the immune response - Secrete chemicals • Examples: monokines, interleukins • play a role in the activation of additional lymphocytes and in the inflammatory response, which accompanies a secondary immune response. - Present throughout the body in such tissues such as liver, lungs, and lympthnodes
What do B memory cells do?
- Can quickly form clone of plasma cells - provide for repeated production of antibodies also form in humoral immune responses.
Tell me about allergic reactions? what are they caused by? What are common allergies?
- Caused by allergen - The specific allergen may be a food, a chemical, pollen from a plant, or a drug. - Common allergenic foods include shellfish, nuts, and strawberries. - occur frequently with drugs such as acetylsalicylic acid (ASA;aspirin), penicillin, sulfa, and local anesthetics
What does the Elisa diagnostic test do?
- Detects HIV antibodies - Used for a number of other diseases
What does the Indirect Coomb's diagnostic test do?
- Detects Rh blood incompatibility
What is Acute rejection?
- Develops after several weeks - Happens when un-matched antigens cause an infection
What is the history of AIDS?
- First case recognized in 1979; HIV identified in 1984 - Evidence of earlier sporadic cases - Now considered to be a pandemic - Occurs in men and women - 2006, CDC: 1 million cases in North America - 2007, UN: 33 million cases globally; 22 million of those in sub-Saharan Africa
What is the Primary response in the immune system?
- First exposure to antigen - 1 to 2 weeks before antibody titer reaches efficacy - During exposure the antigen is recognized and processed, and subsequent development of antibodies or sensitized T lymphocytes is initiated
What are the 3 stages of AIDS?
- First phase - Prolonged latent stage - Final acute stage
What are T lymphocytes
- From bone marrow stem cells - Further differentiation in thymus - Cell-mediated develops when T lymphocytes with protein receptors on the cell surface recognize antigens on the surface of target cells and directly destroy the invading antigens - These specially programmed T cells then reproduce, creating an "army" to battle the invader, and they also activate other T and B lymphocytes - T cells are primarily effective against virus-infected cells, fungal and protozoal infections, cancer cells, and foreign cells such as transplants.
What are the signs and symptoms of Anaphylaxis?
- Generalized itching or tingling, especially in oral cavity - Coughing - Difficulty breathing - Feeling of weakness - Dizziness or fainting - Sense of fear and panic - Edema around eyes, lips, tongue, hands, feet - Hives - Collapse with loss of consciousness
What are self antigens?
- HLA proteins label cells of the individual. - MHC molecules or HLA are useful in detecting changes in cell membranes altered by viruses or cancerous changes and alerting the immune system to their presence. - Present on the individuals plasma membrane - These antigen molecules are coded by a group of genes inherited from the parents, called major histocompatibility complex (MHC) - Immune system ignores self-cells.
What are examples of Hyper sensitivity Type 1?
- Hay fever - food allergies - Atopic Dermatitis, Eczema - Asthma - Anaphylaxis
What are the important chemical mediators and what do they do?
- Histamine, interleukins - Play a major role in the body's immune reaction
What is the agent in AIDS? and how does it take over the body?
- Human immunodeficiency virus - The core of HIV contains two strands of RNA and the enzyme reverse transcriptase, and the coat is covered with a lipid envelope studded with "spikes" of glyco- proteins that the virus uses to attach to human cells - Once inside the human host cell, the viral RNA must be converted by the viral enzyme into viral DNA, which is then integrated with the human DNA. - The virus then controls the human cell and uses its resources to produce more virus particles, and subsequently the host cell dies. - The new viruses can be seen "budding" out of the host cell
What is Systemic Lupus Erythematosus (SLE)?
- IS AN AUTO IMMUNE DISORDER - Chronic inflammatory disease that affects a number of organ systems - The name of this systemic disorder is derived from the characteristic facial rash, which is erythematous and occurs across the nose and cheeks, resembling the markings of a wolf (lupus) - Is characterized by a large number of circulating autoantibodies against DNA, platelets, and erythrocytes - Immune complexes, especially those with anti-DNA antibodies, are deposited in connective tissues anywhere in the body, activating complement and causing inflammation and necrosis. - Vasculitis, or inflammation of the blood vessels, develops in many organs, impairing blood supply to the tissue. The resulting ischemia (inadequate oxygen for the cells) leads to further inflammation and destruction of the tissue. Common sites include the kidneys, lungs, heart, brain, skin, joints, and digestive tract
What is hyperacute rejection?
- Immediately after transplantation - This is a greater risk in patients who have preexisting antibodies, perhaps from prior blood transfusions. - The blood vessels are affected, resulting in lack of blood flow to the transplanted tissue.
What are non self antigens?
- Immune system recognizes specific non-self-antigens as foreign. - Development of a specific response to that particular antigen - Memory cells produced to respond quickly to antigen
What is immunodeficiency?
- Immunodeficiency results in a compromised or a lack of an immune response. - Increased risk of infection and cancer - The problem may be acute and short term or chronic. - Deficits may be classified by etiology or component.
What is the IgA antibody?
- In secretions • Tears • Saliva and mucous membranes • Colostrum
What is the prevalence between cancer and AIDS? What two unusual cancers are often markers for AIDS?
- Increased incidence of all cancers - Unusual cancers are often markers for AIDS. Kaposi sarcoma • Affects the skin, mucous membranes, and internal organs Non-Hodgkin lymphoma • Purple or brown nonpruritic, painless patches • Eventually become nodular
What is Passive Artificial Immunity?
- Injection of antibodies - Short-term protection EXAMPLE: - administration of rabies antiserum or snake antivenom. - Sometimes immunoglobulins are administered to an individual who has been exposed to an organism but has not been immunized to reduce the effects of the infection (for example, hepatitis B).
What is type 4 hypersensitivity?
- Is Also known as Cell-Mediated or Delayed Hypersensitivity - Delayed response by sensitized T lymphocytes to antigens - Release of lymphokines or other chemical mediators that cause an inflammatory response and destruction of the antigen - These skin reactions usually do not occur immediately after contact; these reactions usually take more than 24 hours. EXAMPLE: - Tuberculosis - CONTACT DERMATITIS - allergic skin rash caused by dyes, soaps, metals - Organ transplant rejection
Why is the secondary infection so dangerous when a Pt. has AIDS?
- Is the Primary cause of death - Frequently multiple, more extensive and more severe than usual - Drug treatment often ineffective - Affects Lungs (Pneumocystis carinii )(severe pneumonia) Herpes simplex - Cold sores Candida - Involves mouth and often esophagus
what can anaphylaxis be caused by?
- Latex materials - Insect stings - Nuts or shellfish; various drugs (penicillin or anesthetic injections)
What is secondary or acquired immunodeficincies?
- Loss of the immune response from specific causes - Can occur at any time during the life span • Infections, splenectomy, malnutrition, liver disease, immunosuppressant drugs, radiation, chemotherapy (cancer) - Predisposition to the development of opportunistic infections - Caused by normal flora - Usually difficult to treat because of immunodeficiency - Prophylactic antimicrobial drugs may be used prior to invasive procedures.
What are memory T cells?
- remains in the lymph nodes for years, ready to activate the response again if the same invader returns.
What are the signs and symptoms of Systemic Lupus Erythematosus (SLE)?
- vary because of organ involvement but commonly include: - Arthralgia, fatigue, malaise - Skin rash or joint inflammation which process to lung or kidney involvement - Cardiovascular problems - Polyuria
What happens during the final acute stage of AIDS?
- when immune deficiency is evident, is marked by numerous serious complications. - The categories include general manifestations of HIV infection, gastrointestinal effects, neurologic effects, secondary infections, and malignancies. - Secondary infections and cancer are caused by the immunodeficiency. - Encephalopathy Sometimes called AIDS dementia Direct infection of brain cells by HIV
What is the complement system?
-Activated during immune reactions with IgG or IgM -Involves a Group of inactive proteins numbered C1-C9 circulating in blood -When an antigen-antibody complex binds to the first complement component, C1, a sequence of activating steps occurs -Eventually this activation of the complement system results in the destruction of the antigen by lysis when the cell membrane is damaged, or some complement fragment may attach to a microorganism, marking it for phagocytosis. -Causes cell damage and further inflammation when activated
What are immunoglobulins?
-Antibodies are a specific class of proteins termed immunoglobulins, and are present in different body fluids -Antibodies bind to the specific matching antigen, destroying it. -This specificity of antigen for antibody, similar to a key opening a lock, is a significant factor in the development of immunity to various diseases. -Antibodies are found in the general circulation, forming the gamma region of the plasma proteins, as well as in lymphoid structures.
How does the Immune response work?
-Because of unique antigens, often a protein, on the surface of an individual's cells, can distinguish self from nonself (foreign) and can thus detect and destroy unknown material. -Normally the immune system ignores "self" cells, demonstrating tolerance. -When the immune system recognizes a specific nonself-antigen as foreign, it develops a specific response to that particular antigen and stores that particular response in its memory cells for future reference if the antigen reappears in the body. -Note that a person must have been exposed to the specific foreign antigen and must have developed specific immunity to it such as antibodies before this defense is effective - This response is usually repeated each time the person is exposed to a particular substance (antigen) because the immune system has memory cells - Immune responses that occur after the first introduction of the antigen are usually more rapid and intense than the initial response. - In destroying foreign material, the immune system is assisted by nonspecific defense mechanisms such as phagocytosis and the inflammatory response. - By removing the foreign material, the immune system also plays a role in preparing injured tissue for healing.
What is bioterrorism?
-Biological agents used to attack civilians and/or military personal -May use altered antigenic forms of common viruses or bacteria -Widespread impact on population due to a lack of vaccines
What is Innate Immunity?
-Gene-specific - Related to ethnicity EXAMPLE: as evident from the increased susceptibility of North American aboriginal people to tuberculosis
What are hypersensitivity reactions?
-Hypersensitivity or allergic reactions are unusual and sometimes harmful immune responses to normally harmless substances. -These reactions stimulate an inflammatory response. - There are four basic types of hyper- sensitivities, which differ in the mechanism causing tissue injury.
What do chemical mediators do? and what are some examples?
-Involved in inflammation and immune reactions Examples: histamine, interleukins - Variety of functions -Signaling - Causing cellular damage
What is Passive Natural Immunity?
-Passive immunity occurs when antibodies are transferred from one person to another. - These are effective immediately, but offer only temporary protection because memory has not been established in the recipient, and the antibodies are gradually removed from the circulation - IgG transferred from mother to fetus: • Across placenta • Through breast milk - Protection of infant for the first few months of life or until weaned
Explain tissue and organ transplant Rejection?
-Replacement of damaged organs or tissues by healthy tissues from donors is occurring more frequently as the success of such transplants improves. -Skin, corneas, bone, kidneys, lungs, hearts, and bone marrow are among the more common transplants. -In most cases transplants, or grafts, involve the introduction of foreign tissue from one human, the donor, into the body of the human recipient (allograft) -Because the genetic marrow transplants or in transfused blood products with viable T-lymphocytes (TA-GVHD transfusion-associated graft versus host disease). Rejection may occur at any time:
What is Anaphylaxis?
-Severe, life-threatening Systemic hypersensitivity reaction -Decreased blood pressure caused by the release of histamine -Airway obstruction -Severe hypoxia - It happens by Large amounts of chemical mediators are released from mast cells into the general circulation quickly, resulting in two serious problems. - General or systemic vasodilation occurs with a sudden, severe decrease in blood pressure. - In the lungs, edema of the mucosa and constriction of the bronchi and bronchioles occur, obstructing airflow
What are the components of the immune system?
-The immune system consists of lymphoid structures, immune cells, tissues concerned with immune cell development, and chemical mediators:
What are lymphocytes?
-The primary cell in the immune response is the lymphocyte, one of the leukocytes or white blood cells produced by the bone marrow -Mature lymphocytes are termed immunocompetent cells—cells that have the special function of recognizing and reacting with antigens in the body.
What are antigens (immunogenicity)
-Usually exogenous substances -Cell surface antigens Proteins PolysaccharideS
What is humoral immunity?
Antibodies are produced to protect the body.
Where is the origination of all immune cells?
Bone marrow
What treatment and prevention methods can we take to limit organ transplant rejection?
Immunosuppression techniques - Reduce immune response - Prevent rejection - The major concern with any immunosuppressive drug is the high risk of infection because the normal body defenses are now limited. - The common treatment involves drugs such as cyclosporine, azathioprine (Imuran), and prednisone, a glucocorticoid - The drugs must be taken on a continuous basis and the patient monitored for signs of rejection • Careful dosing to prevent kidney damage • Many drugs in clinical trials
What is cell mediated immunity?
Lymphocytes are programmed to attack nonself cells to protect the body.
What do the antibody producing plasma cells do?
Produce antibodies
What are antigens?
foreign molecules that trigger the generation of antibodies They are usually composed of complex proteins or polysaccharides, or a combination of molecules such as glycoproteins. -Antigens activate the immune system to produce specific antibodies. These specific antibodies are produced by B lymphocytes.
Where does maturation of T cells occur?
thymus
What are the immune cells?
lymphocytes and macrophages -provide the specific mechanism for the identification and removal of foreign material.
