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Immune System, B and T cells
Transcript of Immune System, B and T cells
-T cells participate in the Cell Mediated Response, the response of the immune system once the pathogen has infected cells
-T cells: 4 types
"Helper" T-cells activate and direct cells that can kill pathogens
"Effector" T-cells release massive amounts of a specific effector protein that attach to pathogens displaying specific antigens to mark them for destruction
"Memory" T-cells remember pathogens that were previously encountered by holding effector proteins on the cell membrane for future use
"Cytotoxic" T-cells recognize antigens and effector proteins presented by dying cells and destroys them through release of enzymes that break down the cell B-Cells in the Humoral Response Used in the Humoral Response- The immune response while the pathogen is still in the fluids of the body but has not yet infected cells. The Immune System in Conjunction With Other Biological Systems Circulatory System Active B-cell -always present in the blood and once it receives signal from antigen it:
-clones self to create some copies with the same antibodies on the membrane so that the body will have copies to recognize the pathogen repeatedly throughout life called memory B-cells. This is the mechanism for creating the acquired immune system (the immune system which you are not born with)
-the other clones are Plasma/Effector-Cells, which use the antibody as a template to make approximately 200 antibodies/second to carry out the immune response, moving into the Cell Mediated Response lymphocytes (T and B cells) travel through bloodstream to patrol for antigens and travel to site of infection.
Use circulatory system as means of transport
Diapadesis: lymphocyte signals for cells of capillary to separate, squeezes through to infection site. Structure of B-cell -antibodies imbedded in membrane
-antibodies are pathogen-specific so B-cells only work on the pathogens that they have the antibodies for
-antibodies on B-cell surface serve the purpose of recognizing the presence of a pathogen and begin the B-cell's Humoral Response Lymphatic System filters out organisms that cause disease
produces white blood cells (including lymphocytes)
network of vessels that carries lymph (blood plasma) throughout the body. Lymph includes white blood cells.
distributes fluids and nutrients in the body and drains excess fluids and protein so that tissues do not swell (tempers immune response, helps dissipate immune response). Integumentary System SKIN, hair, nails, etc.
first line of defense against pathogens
physical barrier to entry of an infectious body
exocrine glands secrete sweat and oil. Decrease the pH on the surface of skin and kill microorganisms.
enzymes in sweat can digest bacteria. IMMUNE SYSTEM DISORDERS Acquired Immunodeficiency Syndrome HIV/AIDS the inappropriate immune response of the body against substances and tissues normally present in the body. immune system attacks the body's cells and tissue, resulting in inflammation and tissue damage. Autoimmune Disease Ex: Lupus (SLE--Systemic Lupus Erythematosus) systemic autoimmune disease (or autoimmune connective tissue disease) that can affect any part of the body.
Type III hypersensitivity reaction in which antibody-immune complexes precipitate and cause a further immune response (positive feedback)
most often harms the heart, joints, skin, lungs, blood vessels, liver, kidneys, and nervous system.
Unpredictable course with periods of illness (called flares) alternating with remissions. 9x more common in women than in men, especially in women in child-bearing years ages 15 to 35. Also more common in those of non-European descent (especially Africans) no cure for SLE.
treated with immunosuppression, mainly with cyclophosphamide, corticosteroids and other immunosuppressants.
Can be fatal
Survival for people with SLE in the United States, Canada, and Europe has risen to ~95% at five years, 90% at 10 years, and 78% at 20 years, and now approaches that of matched controls without lupus. WHAT IS LUPUS? CAUSES GENETIC LINK: (maybe). Runs in families, but no single causal gene identified. Multiple genes appear to influence SLE development when triggered by environmental factors. Mutations may occur randomly or may be inherited.
ENVIRONMENTAL FACTORS: exacerbate existing SLE conditions; trigger the initial onset (an infection, a cold or viral illness, exhaustion, injury, emotional stress, stress to the body). No pathogen can be consistently linked to the disease.
DRUG REACTION: Drug-induced lupus is typically a reversible condition. Symptoms generally disappear once the medication that triggered the episode is stopped. Over 38 medications can cause this condition. SYMPTOMS extreme fatigue (tiredness)
painful or swollen joints
anemia (low numbers of red blood cells or hemoglobin, or low total blood volume)
swelling in feet, legs, hands, and/or around eyes
pain in chest on deep breathing (pleurisy)
butterfly-shaped rash across cheeks and nose
sun- or light-sensitivity (photosensitivity)
abnormal blood clotting
fingers turning white and/or blue when cold (Raynaud’s phenomenon)
mouth or nose ulcers Made and mature in the Bone Marrow B cell Receptors TREATMENT WHAT IS HIV/AIDS? CAUSES Receptors are membrane-bound antibodies which have a specific antigen binding site. The antigens recognize the presence of a pathogen and these antigens notify the B-cell which then begins the Humoral response SYMPTOMS TREATMENT Acquired Immunity in Infants From Mother In Gestation: B-Cells can pass through placenta and antibodies can pass through placental fluid.
After Birth: Antibodies can be transferred through breast feeding infants
*T-cells do not pass through placental fluid and are found only in negligible amounts in breast milk
Maternal antibodies often destroy vaccines so vaccines are not effective in young infants because they do not cause the infant to build up its own immune system. Because of this, common vaccines, such as measles, are only administered at one year of age. Human Immunodeficiency Virus Most successful treatments to date have been combinations (or "cocktails") consisting of at least three medications belonging to at least two types, (classes) of antiretroviral drugs. Combination helps prevent acquired immunity from emerging in the virus.
Initially treatment is typically a non-nucleoside reverse transcriptase inhibitor (NNRTI) plus two nucleoside analogue reverse transcriptase inhibitors (NRTIs).
Combinations of agents which include a protease inhibitors (PI) are used if the above regime loses effectiveness.
If caught early, (while not yet AIDS), people with HIV can often live relatively normal lives From Environment Acute HIV: initial period following contraction. Flu-like or mono-like symptoms in some. No symptoms in others. Symptoms most commonly include fever, large tender lymph nodes, throat inflammation, a rash, headache, sores of mouth & genitals.
Clinical Latency: HIV after inital period. Without treatment, can last from about 3 to 20+ years (average 8). Few or no symptoms at first, near the end: fever, weight loss, gastrointestinal problems and muscle pains. Infants develop immune systems largely from exposure to environmental factors that transfer antigens to them. For this reason, many studies have shown that over use of antibacterial products and keeping children from playing outside or with animals can lead to decreased immune efficiency and increase likelihood of development of allergies because the immune system has no antigens for such common things as pollens or animal dander Person-to-person transmission
sexual contact (unprotected)
Exposure to infected body fluids or tissues
intravenous drug needle sharing, contaminated blood transfusion
from mother to child during pregnancy, delivery, or breastfeeding (vertical transmission).
No risk of acquiring HIV if exposed to feces, nasal secretions, saliva, sweat, tears, urine, or vomit unless these are contaminated with blood. Short and Long Term Immune Response- Acquired Immune System A disease of the human immune system caused by infection with human immunodeficiency virus (HIV)
HIV: retrovirus that primarily infects components of the human immune system such as T cells, macrophages and dendritic cells. Directly and indirectly destroys T cells.
Leads to a compromised immune system, so that normally harmless pathogens (such as pneumonia or common cold pathogens) can cause death.
AIDS: <200 T cells per microliter Non-Animal Immune Systems Unicellular Organisms Plants Individual plant cells express receptors that recognize pathogen molecules and then trigger defense responses, which can include cell wall thickening, production of anti-microbial compounds and host cell death. A lot of pathogens feed on living tissue, so if the immediate cells that are being infected die, it stops the pathogen from being able to access nutrients and then it can't spread through the rest of the plant -No immune system.
-By virtue of being unicellular cannot have a "system."
-Are typically preyed upon by viruses. do not have any sort of immune response, but evolve via natural selection to resist a virus Brittle Cinder (Ustulina deusta) B-Cell Clonal Selection Cytokine Storm potentially fatal malfunction of a positive feedback loop in the immune system between cytokines and immune cells hypercytokinemia Positive and Negative Feedback with Cytokines Cytokines are signaling molecules whose job it is to signal to T-cells and Macrophages to come to the cite of an infection. Lymphokines, interleukins, and chemokines all fall under the category of cytokines. Positive Feedback Negative Feedback Cytokines tag a pathogen and when helper T-cells and Macrophages respond, the presence of the cytokines and pathogen simultaneously activate the production of more cytokines by the T-cells and macrophages so that the pathogen can be identified throughout the system. Active cytokines more cytokines -the overreaction of the immune system to particularly pathogenic invaders
-too many cytokines are produced so the excess start to tag healthy cells and macrophages begin to destroy somatic cells which have not been infected
-can lead to heart failure, hemorrhaging, respiratory failure
- often occurs in response to particularly pathogenic influenzas like the bird flu or pathogens like the bubonic plague (hemorrhaging was a result of a cytokine storm) In a normal response of the immune system the production of cytokines is switched off by blocking the DNA binding site where the transcription for the code for cytokines begins.
-when cytokine levels near a toxic concentration then...
-PIAS (protein inhibitor of activated STAT) proteins interact with STAT (signal transducer and activator of transcription) proteins which are responsible for beginning the transcription of, in this case, cytokines,
-PIAS proteins suppress the STAT's so that no more cytokines are synthesized.
- this interaction between the PIAS and STAT proteins will end when more cytokines are needed