Immunity Updated IB Topics PDF

Biology 20 Chapter 11 Blood and Immune System Nelson Pages 348-375  11.1: Components of Blood ▪ Average 70kg person has 5L of blood ▪ Blood ▪ 55% fluid/plasma ▪ 45% blood cells ▪ Plasma ▪ 90% water ▪ 10% proteins, glucose, vitamins, minerals, gases, waste products...

Biology 20 Chapter 11 Blood and Immune System Nelson Pages 348-375  11.1: Components of Blood ▪ Average 70kg person has 5L of blood ▪ Blood ▪ 55% fluid/plasma ▪ 45% blood cells ▪ Plasma ▪ 90% water ▪ 10% proteins, glucose, vitamins, minerals, gases, waste products  Erythrocytes ▪ Red blood cells (RBC) ▪ Transport O2, packed with hemoglobin (oxyhemoglobin) ▪ Biconcave to increase surface area ▪ Enucleated (no nucleus), more room for hemoglobin ▪ Made in bone marrow ▪ Broken down by spleen and liver ▪ Heme into bile ▪ Iron back to liver and bone marrow for reuse  Erythrocytes ▪ RBC’s and low O2 levels ▪ Exercise, high altitude, hemorrhage ▪ Kidneys release REF to stimulate RBC production under low O2 ▪ Anemia ▪ Reduction in blood O2 due to low levels of hemoglobin or poor RBC production ▪ Causes: hemorrhage, dietary deficiency in iron  Leukocytes ▪ White blood cells (WBC) ▪ Outnumbered by RBC and have nucleus ▪ Phagocytes ▪ Destroy invaders by phagocytosis ▪ Move like amoeba(diapedesis) ▪ Use lysosomes to kill, can digest itself too ▪ Pus forms - fragments of WBC and invader ▪ Multiple types of phagocytes ▪ Some WBCs create antibodies (more to come later)  Leukocytes - Five Distinct Classes ▪ 1) Neutrophils ▪ Most abundant/first responder ▪ Cannot renew lysosomes, die after phagocytosis event ▪ 2) Eosinophils ▪ Specialized for allergic reactions and parasites ▪ Do not phagocytose, release chemicals instead - attack membranes  Leukocytes - Five Distinct Classes ▪ 3) Basophil ▪ Start inflammatory response ▪ Similar to mast cells, but circulate ▪ Assist with allergic response ▪ 4) Monocyte ▪ Largest leukocyte ▪ Phagocytosis, can renew lysosomes, long lasting ▪ Differentiate into macrophages (phagocytose) and dendritic cells (present antigens)  Leukocytes - Five Distinct Classes ▪ 5) Lymphocyte ▪ For production of antibodies ▪ Lymphatic system primarily ▪ Slow to respond ▪ Include B and T cells ▪ Help with killing virus infected body cells  Platelets ▪ Aka thrombocytes ▪ No nucleus and produced in bone marrow ▪ Move through blood vessels and initiate blood clotting reactions ▪ Platelet strikes a torn blood vessel —> platelet breaks apart and releases thromboplastin—> Ca2+ and thromboplastin activate prothrombin—> becomes thrombin —> splices fibrinogen —> concerted into fibrin—> wraps cut and seals it ▪ Microbes can’t enter but WBCs can Platelets Platelets  Platelets ▪ Harmful blood clots ▪ Thrombus ▪ Blocks a blood vessel (coronary, cerebral-stroke) ▪ If blood clot moves or dislodges can become embolus ▪ Pulmonary, coronary, cerebral embolisms ▪ Hemophilia ▪ Genetic defect in clotting process Platelets  Artificial Blood ▪ Fluosol ▪ Allows one to avoid blood transfusions ▪ Provides a 5 day temporary period in which one’s bone marrow may replenish RBCs ▪ No blood matching required ▪ No virus, no blood clotting, good for transfusions  Blood Groups ▪ Special markers called glycoproteins are on membranes of some RBCs (inherited) ▪ A, B, AB, O (no markers) ▪ Antigens (glycoproteins) stimulate formation of antibodies ▪ Antibodies (proteins) produced in response to a foreign invader ▪ Act on invading antigen, immune response ▪ Agglutinate - clumping of blood from antibodies binding antigens. Can prevent O2 delivery  Blood Groups ▪ Blood Type A ▪ Has A antigen on RBC ▪ Person makes anti-B antibodies ▪ Blood Type B ▪ Has B antigens on RBC ▪ Person makes anti-A antibodies ▪ Blood Type AB ▪ Has A and B antigens on RBC ▪ Person does not make antibodies ▪ Blood Type O ▪ Has no antigens ▪ Person makes both anti-A and anti-B antibodies Blood Groups Blood Groups  Blood Groups ▪ Rhesus or Rh Factor (inherited) ▪ Rh + (you have Rh factor) ▪ Rh- (you don’t have Rh factor)  Self vs Non-Self ▪ Major Histocompatibility Complex Molecules (MHC class 1) ▪ Identification tags for nucleated cells as “self” so immune cells do not react ▪ Antigen - a substance recognized as foreign and “non-self” ▪ MHC1 differs between people - make transplants hard ▪ RBCs are non-nucleated so have antigens  11.2: The Body’s Lines of Defence ▪ Pathogen: an organism causing disease from Viruses, Bacteria, Tapeworm Fungi, protozoa, flatworms and roundworms Lice Giardia (beaver fever) Malaria More disease! Salmonella Ifluenza Syphillus AIDS  11.2: The Body’s Lines of Defence ▪ Cellular Pathogen - parasite, ▪ Acellular Pathogen - viruses and protozoa, bacteria prions  11.2: The Body’s Lines of Defence ▪ Viruses ▪ Metabolically inert ▪ Require host cell to replicate ▪ Hijack host resources ▪ Inner nucleic acid core ▪ Protein shell/capsule ▪ DNA based - adenovirus ▪ RNA based - retrovirus  11.2: The Body’s Lines of Defence ▪ Prions ▪ Infectious protein ▪ Can make other proteins become infectious ▪ Mis-folded ▪ Proteins aggregate, causing holes in brain - spongiform encephalopathy ▪ High beta sheet count - resistant to denaturation, hard to treat  11.2: The Body’s Lines of Defence ▪ Bacteria ▪ Prokaryotes ▪ Short reproduction cycle, compete with host for resources ▪ Toxic compound production can cause disease ▪ Can cause effects after death of bacteria - why it can cause food poisoning if food is cooked  11.2: The Body’s Lines of Defence ▪ Fungi ▪ Typically attack body surfaces/mucous membranes ▪ Unicellular (yeast) or multicellular (moulds) ▪ Made of branching filaments (hyphae) creating invading threads (mycelium) ▪ Athlete’s foot  11.2: The Body’s Lines of Defence ▪ Parasites ▪ Grows and feeds on host - harming host ▪ Ectoparasites (lives on surface) ▪ Endoparasites (lives within host) ▪ Microparasites (single celled) - protozoa ▪ Macroparasites (multi-cellular)  11.2: The Body’s Lines of Defence ▪ Pathogenesis - process of infection leading to disease ▪ Pathogens are usually species specific ▪ Polio/gonorrhoea specifically affect humans ▪ Zoonotic diseases - disease in animal that can be transmitted to humans ▪ Rabies (dogs), influenza (bird flu), bubonic plague (rats), Covid (bats?) ▪ Transmission via ▪ Direct contact, Contamination, Airborne, Vectors  First Line of Defence: Non-Specific and External ▪ Mainly physical ▪ Skin (acidic secretions - sebaceous glands, physical barrier) ▪ Windpipe mucous and cilia ▪ Stomach Acid ▪ Tears, Saliva and Mucous have lysozyme  Second Line of Defence: Non-Specific and Internal ▪ Non-Specific ▪ Non-Adaptive ▪ The same every time ▪ Phagocytes (WBCs) destroy microbes  Second Line of Defence: Non-Specific and Internal ▪ Phagocytosis ▪ Ingestion of invading microbes by certain WBCs ▪ Foreign bodies enter through penetrated skin ▪ Monocytes (WBCs) migrate from blood to damaged tissue and turn into macrophages that ingest the invader. ▪ Use digestive enzymes  Second Line of Defence: Non-Specific and Internal ▪ Inflammatory Response ▪ Tissue damage occurs ▪ Mast cells (localized) and Basophils (circulating) relate histamine ▪ Histamine triggers vasodilation and increased permeability, allowing more leukocytes ▪ Increased blood flow, heat, fluid permeability (swelling/tenderness) Second Line of Defence: Non-Specific and Internal  Second Line of Defence: Non-Specific and Internal ▪ Fever Response (can be dangerous) ▪ Reduces microbial growth - denaturation of enzymes ▪ Activate heat shock proteins - help immune response ▪ Activated leukocytes release pro-inflammatory chemicals - cytokines ▪ Cytokines —>anterior hypothalamus—> prostaglandin production —>increased body temp Second Line of Defence: Non-Specific and Internal ▪ Example : Fever ▪ Macrophages digest invaders ▪ Release chemicals, reset body temp to 40oC, making it difficult for bacteria or invaders to survive ▪ Can be unsafe as you know  Third Line of Defence: Specific and Internal ▪ Some macrophages migrate throughout the body some reside in certain tissues (brain, lung, kidney, etc) ▪ Compliment proteins ▪ Antimicrobial ▪ Activated by foreign invaders ▪ Help phagocytes ingest invaders ▪ Protective coating, immobilize ▪ Puncture  Third Line of Defence: Specific and Internal ▪ Lymphocytes (special type of WBC) ▪ Produce antibodies against foreign antigens ▪ Types ▪ T-cells (produced in bone marrow, stored in thymus gland - seek out intruder and signal attack ▪ B-cells make antibodies, agglutinate  Third Line of Defence: Specific and Internal ▪ Antibodies ▪ Y-shaped proteins that are specific to foreign antigens ▪ Tails are the same, arms are different and specific ▪ 4 polypeptide chains connected via disulphide bonds ▪ Attach to invading microbes and debilitate them ▪ Variable region binds pathogen ▪ Every antibody recognizes a unique antigen Third Line of Defence: Specific and Internal  Viruses ▪ Use receptor sites as point of entry ▪ Inject hereditary material into cell, hijack it to make more virus ▪ Different viruses for different cells ▪ HIV virus (Human Immunodeficiency Virus) ▪ Attach to receptor site of T cells ▪ Protein coat of virus hides in the very cells that are meant to destroy them ▪ Antibodies bind to virus and prevent virus from binding and entering target cells ▪ Viruses evolve to change their shape to avoid antibodies over time  Specific Response ▪ Bacterium enters body ▪ Macrophage engulfs bacterium and pushes foreign antigens to the outer membrane ▪ Helper T cell recognizes foreign antigen and produces lymphokine signal ▪ Lymphokine causes production of B cells, which identifies antigen and makes antibodies against them ▪ Antibodies attack and bind ▪ Helper T cell activates killer T cell which punctures and marks holes in invader ▪ Suppressor T cells signals stop of immune response Specific Response Specific Response  Specific Response ▪ Antigen fragment ▪ —> helper T cell ▪ —> cytokines ▪ —> stimulate B cells ▪ —> produce antibodies and divides into clones - plasma cells via clonal selection ▪ —> short lived ▪ —> some turn into memory B cells  Specific Response ▪ Memory B cells remain in blood and release steady, slow supply of antibodies Specific Response Specific Response  Specific Response ▪ Blueprint of foreign antigen stored in memory T cell ▪ Memory T cell ▪ Generated during infection ▪ Remain in blood for many years ▪ Responsible for immunity for years ▪ Prions ▪ Penecillin  Humoral vs Cell-Mediated Immunity ▪ Humoral Immunity ▪ Process of antibody production from pathogenic antigens that are released from B cells ▪ Cell-Mediated Immunity ▪ Targets endogenous antigens ▪ Cancer and virus infected cells are self cells - hard to distinguish ▪ Antigens are combo’d with MHC1 of infected cells ▪ Helper T-cells identify them, trigger cytotoxic T- cells to attack  Types of Immunity ▪ Active Immunity ▪ Production of antibodies and memory cells ▪ Passive Immunity ▪ Antibodies from other sources, no memory cells produced  Antibiotics ▪ Kill/inhibit microbe metabolism ▪ Viruses don’t have metabolism, therefore don’t affect them ▪ Specific to prokaryotes ▪ 70S, cell wall, key enzymes ▪ Antiviral medication target virus enzymes or capsule components  Antibiotics ▪ Narrow spectrum - specific targeted bacteria ▪ Broad spectrum - non-specific ▪ Natural selection to spread resistance - conjugation via pillus ▪ Antibiotics everywhere/overprescribed - bacteria over-exposed ▪ Ex) Golden Staph (MRSA - Methicillin Resistant Staphylococcus aureus)  Penicillin ▪ First antibiotic, 1928 ▪ Accidental discovery, contaminated plates ▪ Alexander Flemming ▪ Mold must have released substance to kill bacteria  Penicillin ▪ Sir Howard Florey, 1940, medical applications shown ▪ 8 mice infected with virulent stain ▪ 4 mice treated with penicillin ▪ 4 mice lived ▪ 1945 Nobel prize ▪ Many derivatives formed ▪ Methicillin  HIV ▪ Human Immunodeficiency Virus (HIV) ▪ Retrovirus - RNA to DNA integrated into host cell ▪ Causes symptoms and infections resulting in Acquired Immunodeficiency Syndrome (AIDS) ▪ Targets helper T-cells, goes latent, infected cells replicate ▪ Virus activates, destroying T-cell hosts, limiting antibody production ▪ Opportunistic infections take hold  HIV ▪ Transmission through bodily fluids ▪ Unprotected sex (use condoms!), blood transfusions, breastfeeding, etc ▪ Some people immune ▪ HIV requires the CD4+ receptor on T cells, people who lack it can’t be infected ▪ Global problem, effects can be minimized, harder to do in poor nations with poor education and limited female reproductive rights  Vaccinations ▪ Vaccinations introduce antigens that cannot trigger disease ▪ Innate primary immune response causing memory cells to be made ▪ True pathogen exposure triggers fast antibody response (secondary immune response) ▪ Sometimes boosters required, different memory cells have different life spans  Vaccinations ▪ Herd Immunity ▪ When individuals not immune to a pathogen are protected from exposure due to surrounding immune individuals ▪ Epidemic - increased infection in a region ▪ Pandemic - epidemic spread over large area (continents, etc)  Vaccinations ▪ Small Pox - first infectious disease eradicated ▪ Eliminated - disease stops circulating in a region ▪ Eradicated - eliminated worldwide ▪ Last known case was 1970, targeted by WHO ▪ Possible because ▪ Easily identified, no animal vectors, short lived infectious period, global cooperation, no booster needed  Monoclonal Antibodies ▪ Monoclonal antibodies - antibodies from a B cell clone ▪ Inject mouse with antigen —> mouse makes plasma cells —>isolate and fuse with tumour cell —> creates hybridoma —> immortal antibody producing cell line ▪ Makes large quantities ▪ Used in pregnancy tests ▪ Can inject in rabies patients ▪ Can be used to target cancer cells  Monoclonal Antibodies ▪ Diagnostic use of monoclonal antibodies ▪ hCG is a hormone produced by pregnant women ▪ Free monoclonal antibody binds hCG - this antibody can change the dye color (show positive result strip) ▪ Second monoclonal antibody is not free, but found to test site and also binds hCG, forming a hormone-antibody sandwich ▪ This causes positive results to show up Monoclonal Antibodies Monoclonal Antibodies Monoclonal Antibodies  11.3: Malfunctions of the Immune System ▪ Immunodeficiency Diseases ▪ Caused by HIV, Hereditary, Drug exposure and Cancer Therapy ▪ Inappropriate attacks of the Immune system against non-threatening agents ▪ Allergies and Autoimmune disorders  Allergies ▪ Immune system mistakes harmless cells as harmful ▪ Tissue swelling, mucus secretion, constricted airways ▪ Anaphylactic Shock ▪ Cells that think they are in danger release histamines and swell up/hives ▪ Occurs fast ▪ Difficulty breathing ▪ Need antihistamines from hospital, api-pen short term solution Allergies  Autoimmune Disorders ▪ Immune system mistakenly attacks body’s own cells ▪ Renegade lymphocytes treat own cells and foreign ▪ Usually held in check ▪ Mutated T and B cells can bypass this ▪ Thought suppressor cells might tell macrophages to engulf the renegades ▪ Arthritis (connective tissues) ▪ Rheumatic fever (Scars heart muscle) ▪ Type 1 Diabetes (Against Insulin-producing cells of pancreas) ▪ Lupus (antigen-antibody complexes build up on blood vessel walls, kidneys, skin, etc) ▪ Multiple Sclerosis (against myelin sheath cells of nerves) ▪ Weekend Suppressor T cells (age, hereditary, disease) ▪ Treat with Immune Suppressant drugs Autoimmune Disorders  Organ Transplant Rejection ▪ Immune system sees new organ as foreign and attacks ▪ Major Histocompatability complex (MHC) ▪ Unique to each individual, cell surface proteins ▪ Try to match MHCs of donor to recipient to limit rejection ▪ Immune suppressant drugs ▪ Greater risk for infection trade off