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Lecture

IMMUNIZATION-Microbio- lec notes.docx

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Department
Biology
Course
BIOL 2900
Professor
Motti Anafi
Semester
Fall

Description
IMMUNIZATION AND VACCINATION Immunization and Vaccines Vaccins are produced by growing microbes in a labratory using culture vessels. Because viruses need a host cell to reproduce, they are cultured inside chicken eggs. For example the flu vaccine. --Blood=cells + plasma --antibodies secreted out of the cell into plasma (when doing serum tests) Plasma=serum eg,. Antibodies, seriological tests Cells=B-cells – secretion of soluble Abs o Put blood in centrifuge and run for 10 minutes – immediately after you will see that the lower fraction consists of cells, debris, etc and the top will have antibodies and the plasma T-cells- come in two different types, helper cells and killer cells o helper cells- primary task is to activate B cells and killer T cells o killer T cells- specialized in attacking cells of the body infected by viruses and sometimes also by bacteria (do not secrete immunoglubulins) Immunization - the administration of any antigenic inoculum, which are called vaccines. Vaccine - a substance used to stimulate the production of antibodies and provide immunity against one or several disease, prepared from the causative agent of a disease, its products, or a synthetic substitute, treated to act as an antigen without inducing the disease Different Modes of Acquiring Immunity *Remember- the immune response has two steps 1) Primary Exposure: - very first time you see the antigen - this is usually when you get sick - your body makes the antibodies while you are sick 2) Secondary Exposure: - second time you are exposed to the antigen - antibodies that was produced in the first exposure mark the antigen for destruction so you don't get sick PASSIVE: (using plasma) 1. Naturally (baby) - - the body passively recieves antibodies from another individual. - passed from mom to baby --babys born with no immune however have antibodies from mom. These antibodies last approx. 3 months, with some lasting as long as 6 months. (just before birth into circulation)short term protection from pathogens that mom is immunize against as only antibodies are attained, not immune cells, therefore the protection is temporary. --antibodies from mom through breast milk (ie, gastro problems) --acquired immunity is passive and natural 2. Artificial --antibodies from someone else ie. Ab injection --used as a drug (means after a short time the pt. is not going to have defence in the future) --no memory cell will develop for future protection --given to a person in urgent situations to provide protection for short-term (eg. Snake bite) ie. Rabies and Antivenom. ACTIVE: (activating cells with antigen) – acq’d when body makes its own Abs or T cells to an Ag - active imm is mainly a method of prevention 1. Naturally --being exposed to pathogens --occurs when the body responds to exposure to pathogens and environmental antigens by mounting specific immune responses ie. getting the flu -- end up completely immune this way 2. Artificial --active vaccination (letting the body think the pathogen in the body by form of vaccine, activation of Bcells and Tcells formation occur) --introduce immunity by introducing antigens in the form of vaccines ie. flu shot --end up not completely immune; active vaccination creates long term immunity how ever flu are exception as the flu virus changes all the time and each time different version is introduced to the body. in the cases of other diseases active vaccination create complete protection from the diseases. Humoral Adaptive Immunity (Ch. 16 p. 490) Humoral Immunity: - antibody mediated - Ab are produced by plasma cells (mature B lymphocytes) - immunoglobulins are various types of Ab - here the antigen triggers the B cell - the plasma cell (mature B cell) is located in the lymph node; the antigen enters - the plasma cell produces an antibody specific to the triggering antigen - some of the antibodies form the antibody/antigen complex (does not kill Ag) - this activates the complement which destroys the complex by way of an inflammatory response - some of the other antibodies become a memory cell - these cells hang out in the lymph nodes to mount a quick immune response next time! - this all stops when the antigens are all bound Cell Mediated Immunity - immune response initiated by recognition of a foreign antigen by a T cell - intracellular pathogens (virus), fungal infections, rejection of transplanted tissue, contact hypersensitivity, and tumor immunity - if any get into your body its a T cell response - antigen triggers the T cell - T cell meets the antigen; this causes the T cell to morph into a cytotoxic T cell (CD8) specific to the antigen - some kill the antigen all on their own - others become memory cells - all of this cannot happen without helper cells - when we no longer need anymore, the suppressor T cell tells to stop Major Histocompatability complex - all cells have them - identifies each one of your cells as your own so that your body doesnt attack its own cells - Discovered when trying to graft animal tissue into another animal. Recipient rejected tissue very quickly and activated immune response very quickly to graft. Rejection occurs because of antigen found on unrelated cells contained in the graft Antigens (Ag) --are substances that induce a specific immune response and subsequently react with the products of a specific immune response --everything you have in the body related to immunity (can be a virus, Antibodies (Ab, immunoglobulins, Ig) --are proteins in molecules that are produced by plasma cells in response to an antigen and can bind specifically to that antigen --antibodies recognize foreign pathogens (antigens) and help destroy them, then attract phagocytes which devour the antibody-antigen complex Passive Immunization --natural: placental transfer of IgG (systemic Abs) from mother to newborn --after baby born, breast feeding gives antibodies to defend GI tract (transferring IgA) --artificial (antibodies from other people) --antibodies made from an immune animal (horses, guinea pigs) Disease Product Use Rabies Rabies Ig Post-exposure, locally (administered with rabies vaccine) vaccinia Vaccinia Ig from Treatment of progressive vaccinia infection usually human resulting from smallpox vaccination in immunocompromised individuals Varicella (chicken Varicella-zoster Ig Post exposure in high risk individuals pox) Cytomegalovirus Hyper-immune Prevention, used most often in organ transplantation (CMV) human Ig patients Hepatitis A Pooled human Ig Prevention of Hep A infection Hepatitis B Hepatitis B Ig (HBIG) Prevention in high risk infants (administered with hep B vaccine) Snake and other toxic Specific IgG (from Post exposure treatement bites horse) Hypo-gamma- Pooled human Ig Prevention of many diseases in patients with an immunie globulinemia disorder characterized by a reduction in types of gamma globulins (ex. when people do not make any anitbodies) Post Exposure Passive Immunization- Bacterial Toxins Diphteria- Product (Specific Ig from horse-Avial of Diphteria antitoxin, dated 1895. Exotoxin secreted by bacteria). Use- Treatment of Diphteria infection. Botulism- Product (Specific Ig from horse). Use-Treatment of wound and food born forms of Botulism is treated with botulism immune globulin-baby BIG. Tetanus --Ig from human --treatment if tetanus infrection Post Exposure Passive Immunization Against Viruses As long as the virus is not in the system, antibodies can be injected around the injured part to capture as much of the virus, however there is a chance that virus has gotten into the neurons and can eventually lead to the nervous system - passive immunization is just part of the treatment Rabies – Product (Rabies Ig) - Normally vaccines are to be administrated as a prevention before infected by pathogen – but with rabies, people are getting vaccination after being exposed (incubation is very long) Vaccinia (small pox) – Product (Vaccinia Ig, from human)- Treatment of progressive vaccine infection usually resulting form smallpox vaccination in immunocomprimised individuals (light virus, controlled quite well if immunity is working fine, however if immunocomprimised there is no control over the vaccinia and can cause an infection o -mainly army getting vaccinated with small pox o poeple vaccinated are likey to give blood Varicella (chickenpox) – Product (Varicella-zoster Ig) – Post-exposure in high risk individuals…not 100% immunity, vaccine itself is very sensitive, frozen -20 degrees Celsius, run to doctors office and within 30 mins must receive vaccine o the older you are when you get this virus, the worse it is o also have vaccine for shingles (which is same virus, but when you are getting it as an adult you get 10x amount of virus which can cause shingles) o can be very painful, even after you have the illness, no control of virus by immune system which is why shingles develops – hence why we need vaccination As long as the virus is not in the system, antibodies can be injected around the injured part to capture as much of the virus, however there is a chance that virus has gotten into the neurons and can eventually lead to the nervous system (this process (incubation period) can take a very long time – up to 18 months) – it depends on where the virus was injected – passive immunization is just part of the treatment. Prevention of Viral Infections by Passive Immunization Cytomegalovirus (CMV) – Product (Hyper-immune human Ig) – Prevention, used most often in organ transplantation patient o You need to kill all immune cells in bone marrow, several weeks you have no immune systems at all, in order for new organ to revamp your immune system afterwards o Viruses are still in your system - ex. CMV…can awaken and attack body, therefore this vaccine is given to prevent that Hepatitis A - Product (Pooled human Ig) - Prevention of Hepatitis A infection Hepatits B – Product (Hapatitis B Ig, HBIG) – Prevention in high-risk infants, administered with hep B vaccine; passive immunity) - With time, immune system can help fight hep B but if it lasts for more than 6 month then it is considered a chronic infection and infected for life. o Transmitted through blood and bodily fluids (sex) o If mother infects newborn…baby will have chronic infection for life, leading to cirrhosis/liver cancer o During delivery, infection is fresh in baby, treated within 72 hours before discharge with antibodies o Treatment of antibodies is key because chances are virus is not within the liver yet so it can target the virus before entering the cell. o If acuired for 6 months and no signs of recovery, then is it considered a chronic infection. Passive Immunization-antivenin Snake and other toxic bites (can cause paralysis). - Product (Specific IgG from horse) – Post exposure treatment o Milking snakes, inactivate the toxicity and inject modified venom to horses, creating horse serum (antivenom) o injecting venom to horses because they have no side effects. Hypo-gamma globulinemia – Product (Pooled human Ig) – Prevention of many diseases in patients with an immune disorder characterized by a reduction in all types of gamma globulins o Genetic disease, passed on by generation o not making enough antibodies Advantages and Disadvantages of Passive Immunization Advantages o Immediate protection-antibodies deal with the problem immediately Disadvantages o no long term protection (because we are not using memory cells. If you are infected with the same pathogen again, your immune system will not be prepared) o Risk of infection with unknown pathogens e.g. 80's - Hepatitis B/C and AIDS o Serum sickness ( a reaction similar to allergy, this is a form of secondary immune response as a result of the protein and antibody injection in order to protect the body from the viral infection) Prevention and therapy of infections o Most of the damage to the celss during infections occurs very early, often before the clinical symptoms of disease appear. o This makes drugs treatment of infection irrelevnt in many cases. o Prevention of infection is better and cheaper. o Vaccines are probably the best way to prevent a disease. o Flu shot is a prevention tool – it will prevent the symptoms associated influenza o Price for getting a flu shot is much less than treating a patient in ICU/hospital for the disease. o Immunologist have formulated vaccines that have proven to significantly reduce the number of cases of infectiouse diseases. They are constantly forming new vaccines that provide maximum efficacy and safety. How to make vaccination strategies Natural Artificial o Attenuated organisms (Chickenpox vaccine) o Killed organisms (influenza vaccine) Exposure to sub-clinical infections o Toxins/ toxoid o Subcellular/ small fragments o DNA vaccine (if you take naked DNA and inject it, some cells will pick it up and make proteins and activate immune system) TYPES OF VACCINES Attenuated (Live) Vaccines -Virulent microbes with reduced virulence (attenuation) -They infect a host, causing infected cells to produce endog
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