Biology | Higher education » The immune system

TYPCS {)f PflJH{)GCNS: Viruses: flu, cold, chicken pox, polio .• .EYngl: athletes foot, toenail fungus Bacteria: E. coli, TB, botulism, tetanus Protozoa: amoeba, malaria .• Flatworms: flukes, planaria .•• Roundworms: threadworms (cause elephantitis) Airb.orne: we breathe it into lungs Water-borne: we drink it and it enters into intestine Food-borne: we eat it and it enters into intestine Insect-borne (virus or bacteria carried by insect): pathogen injected into bloodstream via a bite/sting .DirectCo: contact with skin or saliva : oral, anal or vaginal sex The body has three lines of defence to fight off invaders The first two are non-specific (do not distinguish between invaders) The third is specific (it is our immune system) Made of skin and mucous membranes (in nose, eyes, etc.) • Skins secretions are acidic • Enzymes in tears, saliva, mucous, and sweat kill bacteria and other invaders • Mucous traps invaders in airways and cilia sweep the invaders out

of respiratory tract Kicks in when 1st line of defence fails and an invader enters the body Composed of Leukocytes (White Blood Cells) Leukocytes engulf invaders and digest them All cells have markers on their membranes The immune system recognizes the bodys cells and does not produce antibodies to fight these cells The markers on invading cells are recognized as antigens {antibody generators), and the immune system causes antibodies to be made against them IMMUNE SYSTEM c~+o+o~Lc Memor~ T cell T cell TVJ~mu~ L~mpVJ •••• •• node~ ~pken ••J •• Long bone (mvlrrow) --?ICil~tYlCil ~ cell cell L£lJKCCYT£S The blood contains two types of white blood cell or leukocytes Phagocytes ingest bacteria by endocytosis Lymphocytes produce antibodies flNTIBODIES • Antibodies are proteins that recognise and bind to specific antigens • Antigens are foreign substances that stimulate the production of antibodies • Many of the molecules on the

surface of viruses and bacteria a re antigens Section 11 .1 1: Antigens in blood transfusion Read the passage and summarize the impact of receiving the wrong blood group by transfusion. Con~to,nt region - lllijnf cmtn -l+e<;iv~ cno,in BL{){)D TYPE Donor Serum Red blood c-elk; frOtVl indivi4w;;i" of +~pe from indivi4w;;i" of 1jpe A --- ---- --- -•• • - -· No Anti-e, A I +· +· mtibodie~ gg lA lrlv ton eiiggltAtlnvltion No eiiggltAtlnvltion 0 No eiiggltA+Lnvl+ion No Agglutination of blood cells mtibodie~ No to A or e, eiiggltAtirlv ion 0 No No eiiggltAtlnvltion eiiggltAtlnvltion •• • No eiiggltAtLnv1tion flNTIC£NS Immune defence~ ~ fungL Vtru~e~ foretgn ~ub~+~nce~ Non-Lmmune defence~ I Tr~n~pl~n+ b~nder 0 Antigen Activate B-cell i Clone Memory Cell Activate Helper T-cell Antibody Production: Summary Plasma Cell + 0 Macrophage Antibodies STEP I: flNTICEN PRESENTflTICN Antigen Macrophage Macrophages

take in antigen by endocytosis The macrophage processes the antigen and attaches it to a membrane protein called a MHC protein MHC rotein STEP 2: flCTIIJflTl()N ()f HELPER T-CELL Helper T-cell binds to macrophage presenting the antigen Macrophage sends a signal to activate the helper T-cell STEP 3: flCTllJflJl()N ()f 8LYMPHCCYTES B-cells have antibodies in their cell surface membranes Antigens bind to the antibodies in the surface membranes of B-cells () Inactive 8-cel I Antibody - Antigen An activated helper T-cell with receptors for the same antigen binds to the B-cell SIGNAL The helper T-cell sends a signal to the B-cell, activating the B-cell. STEP 4: PR()Llf£Rf1Tl()N The activated B-cell starts to divide by mitosis to form a clone of plasma cells. Plasma cells are activated B-cells with a very extensive network of rough endoplasmic reticulum. n Plasma cells synthesize large y amounts of antibody, which the;) A-.JJr !t V i~ ~ excrete by exocytosis. J. JY

i"" JJf y ~--c J.r ~t If an antigen invades your body a second time, a much faster response occurs which produces much larger quantity of the required antibody. When activated B-cells are dividing during the primary response, some cells stop dividing and secreting antibody and become memory cells. Large numbers of memory cells remain in the body for a long time, and are capable of producing large amounts of antibody very quickly when stimulated. B CELLS IN flCJl()N: Antigen molecule, -=::::::::: The clone, of p~,moi cell, ,ecrete the ~ +ype of v1ntibodie, ~pecific v liibo1f. molecule, ,ecre+ed b1 p~,moi cell, Kognity (2020) 10~ S~condCJiY"f ltYltYlU.ne PRIMflR flN SECVNDflR RESPVNS s:: i~ i~ ~ si ~:e l" ~ ~econd -ey.po~ure to otrrligen A I~ fir~ -ey.po,ure +o c:tn-tigen A :s ~c-- re,pon,e +o ~nA -:Pri~r~ immune re~pon~e to otritigen A 10 2 + S IQI 10° .-0 --r- - ir -- 7 ll- -.-- -=r- -. -- -.-- -,--- - - . - -- 2.1

Kognity (2020) lnvoid~ microbe ~ J-Helper T cell .Activmed e> cen • • Microbe rn,,rJ::.ed for derncfion Kognity (2020) While Fleming is credited for discovery of penicillin, he never thought it would be useful in the body. Florey and Chain are the scientists responsible for developing Flemings discovery into a medic a I treatment: https://www.youtubecom/watch?v=tjGIZ6eNGBA White blood cells release histamine in response to allergens. Histamine causes capillaries in the affected area to dilate, and become leaky Histamine is responsible for the symptoms of allergic reactions: itching, fluid build-up, sneezing, mucous, inflammation. Rashes and anaphylaxis (severe swelling) can occur PRODUCING M()N()CL()Nfll flNTIBODIES Large amounts of monoclonal antibodies can be made commercially Antigens that correspond to the desired antibody are iniected into an animal B-cells producing the antibody are extracted The B-cells are fused with tumour cells to make a

hybridoma, which will make a lot of antibodies, fast The antibody is extracted from the hybridoma cells Used in pregnancy tests, drug tests, and COVID-19 Rapid Tests Components of a Pregnancy Teat Reaction Site Test Site Control Site Free antibody + dye (traps hCG) enzyme Fixed antibody + dye (traps hCG) substrate Fixed antibody + dye substrate (traps free antibody) t yy I I t Reaction Site Where you pee z I I , Test Site Determines if pregnant ~ Control Site Proves test is working ~ ~ Active Immunity: Organism produces its own antibodies after being exposed to a pathogen Takes time to develop Natural immunity Passive Immunity: Organism acquires the antibodies from an outside source {mothers colostrum/ placenta) Immediate effect Artifici a I immunity ltJHY IJflUINflTICN? The first vaccine produced was the one for smallpox 1 By exposing someone to dead/weakened/ related pathogen, they will produce memory cells against the pathogen Usually vaccinate

against dangerous illnesses (polio, measles, smallpox . ) The Untold Story of the First Vaccine - YouTube Melli 2-04 C Senego,I GtuineOl, Sierrn, cote dIvoire Liberiu, "- • 2-014-2-015 Leone,- ( ~pede~ 0 201Lre ebol01vLru~ 0 ~udoin eboloivLru~ • Toit fore~+ eboloivLru~ • f?undtbug~o ebol01vtru~ NutYJber of coi~e~ 1-10 o II - 100 0 IOI - ir2.S 0 0 >it2.S (qo,bon Congo Derviocrntic Republic of tne Congo 2.0l~l019, 2-011, 2-014 Count of total cases of COVID-19 500,000 and higher 80,000 to 499,999 15,000 to 79,999 2,500 to 14,999 500 to 2,499 ~ 1 to499 D o □ Coronavirus disease (COVID1 9): Outbreak update Canada.ca - Note· The total number includes publicly reported confirmed and probable cases. On First Nations reserves numbers reported to lnd1Qenous Services Canada may be counted in tile provincial and temtonal total numbers. on First Nations reserves Eiifi·iii Total Fii+iii Active Recovered Deaths COVID-19 in Ontario: A detailed look

at coronavirus numbers (ctvnews.ca) 0 1.0 45 2.091 3.136 The R number, crocheted. YouTube C()IJID-19 IJflUIN£S Watch this SciShow to see how the mRNA vaccines were made, and how they differ from traditional vaccines • LIVE-ATTENUATED VACCINE • INACTIVATED VACCINE SUBUNIT VACCINE VIRAL VECTOR VACCINE Why It Actually Took 50 Years to Make COVID mRNA Vaccines You Tube estern Student Outbreak Alpha visualization 8-Sep 9-Sep 10-Sep 11-Sep ••• •• • ••• •• • Ep,sode ~ le foe • • • Mectln1on c.mpus How Western students spread COVID-19 to their classmates CTV News Episode date for: Episode date for: Spent day HOUW!#3 toe- l4UOpm,I lowri. tJIIOWU du~ to m111bw& Hu,.,,, ., House Ill Hou~#Z 12-Sep A toplhllfll.t ditt.11,cq: Crunch Fttness House#2 •C. • • cu o.,1 A A outd- ·-· IMsllltlllll n , La Cuclil1 111--10,,.,) - OG •• w11hftlend N1tnt4WC. CD • R.oldhoute t · 10--1lpia) I

Shoflllrc wtlh friend ~• mutd,.e A lost lo,,. 111 in w nt wc.jon •• • llt,in1 1n ) 000 Sh,•ed/ ;aidrinl: - - " inltk Sh11edu, ride home Chuck s Ho=ll3 W;atdwi b;at e tW l•"1t lWih--1 • • Woskird11,.1 tha n ~Uion Loot Lowe L01t love Wo.fd ,-Oh • ~ !lltoo W(nfdv,i1. •• ~~. ~ •• •• i!l«ii• on ! S,ha,ed car liclehome ride home , u°" --· Lawri!lt llnlit nt.41• llOn-Mill .it, CD R£f1DING TflSK: Read Section 11.14 and summarize how smallpox was eradicated, as well as complete the section questions Read Section 11.15 and summarize epidemiology and vaccination programs and complete the section questions fllDS flOOVIRED IMMV CDEflCIENCY SYNDROME) Cause: Caused by HIV (Human Immunodeficiency Virus) Virus attacks T-lymphocytes - eventually, body is unable to produce antibodies This will render the person unable to fight the simplest of infections, which will ultimately lead to their death C~it: NIAIC

TRflNSMISSION HIV cannot live long outside the body It cannot easily pass through the skin {cant be transmitted through touch) Must be transmitted via body fluids from infected to uninfected person The most common methods of transmission of HIV are: Unprotected sex with an infected partner / Sharing needles with infected person Almost eliminated as risk factors for HIV transmission are: Transmission from infected mother to fetus Infection from blood products hJH£N IJ£SS£LS B£C()l1£ Dfll1flt£D: A semi-solid clot is formed from liquid blood. Why? • To stop blood flow • To prevent the entry of pathogens • Vasoconstriction • Formation of a platelet plug • Formation of a blood clot R£MIND£R:PL~T£L£TS Cell fragments that circulate with RB Cs and WBCs in the plasma Involved in blood clotting 1. IJflS()C()NSTRICTl{)N Slows blood flow and reduces blood loss 2. PLflT£L£T PLUG When a blood vessel is damaged, collagen fibres are exposed Platelets are

attracted to the collagen and become activated This causes more platelets to aggregate at the site. 3. BL()()D CL()JTING Clotting factors are released EITHER from the damaged tissue cells or the platelets The clotting factors set off a series of reactions where the product of the first reaction is the catalyst for the next reaction This happens for two reasons: • To ensure a clot forms only when necessary · To enable a very rapid response TH£ f CRMflTl()N ()f TH£ CL()J In the last stage of the chain reaction, f ibrinogen, a soluble plasma protein is converted to insoluble fibrin by thrombin This forms a mesh, that will catch even more platelets Clotting Factors 7 Prothrombln Thrombin 7 Flbrlnogen (soluble) Broken Activated platelet •• . • Damaged Blood Vessel Injury to vessel lining triggers the release of clotting factors Formation of Platelet Plug Vasoconstriction limits blood flow and platelets form a sticky plug Fibrin (insoluble) Fibrin strands 7

Development of Clot Fibrin strands adhere to the plug to form an insoluble clot OOROtlflR THROl18{) IS e,iood dot . Cviole~terol plv1iue Arter~