Immunology Midterm

Question 1

What is the difference between innate immunity and acquired immunity?

Answer 1

Innate: defense mechanism from birth. Often non specific (ie skin)

Acquired: defense mechanisms acquired by exposure to specific pathogens

Question 2

What are the three lines of defense? What are examples?

Answer 2

1. First - surface protection - anatomical (cilia), physiological (skin), genetic (32bp deletions), non specific chemical barriers (stomach acid)
2. Cellular and more specific chemical barriers - enzymes, phagocytosis, inflammation, fever
3. Specific Immune responses - B&T lymptocytes

Question 3

What is the mucociliary escalator/ blanket?

Answer 3

System of defense found in the trachea. Involves epithelial tissues (physical), mucous secreted to trap particles (chemical) and cilia to sweep mucous out of the trap (anatomical)

Question 4

What are some examples of first line behavioural barriers?

Answer 4

1. Hygiene - handwashing, avoiding sweage
2. Contagion avoidance
3. Healthy lifestyle choices

Question 5

What are some examples of first line physical barriers?

Answer 5

1. Skin - can be breached. If so, increases risk of entry
2. Mucous/ Wax - lines POE to prevent entrance of pathogens

Question 6

What are some examples of first line chemical barriers?

Answer 6

1. Acid - stomach acid, lactic acid in sweat
2. Salt - in tears or sweat
3. Proteins - lysozymes and defensins in tears, digestive ensymes

Question 7

What are some examples of a first line genetic barrier?

Answer 7

HIV-1 (R5) partially requires CCR5 cells to infect.

Some caucasians have a 32pb deletion which can lead to partial resistance to infection

Question 8

How does H. Pylori overcome first line defenses?

Answer 8

Physical - overcomes physical by using flagella to burrow into the mucosal layer of the stomach

Chemical - once inside the mucosal layer, releases a basic substance to neutralize the stomach area

Genetic - h. pylori has adapted to survive in the human stomach

Question 9

What cells are not part of the innate system?

Answer 9

B & T lymphocytes

Question 10

Where are WBCs found in the body?

Answer 10

1. Blood stream
2. Lymphatic vessels
3. Reticuloendothelial system - meshlike network of connective tissue that holds the tissue together
4. extracellular fluid

Question 11

What is the difference between plasma and serum? What is the buffy coat?

Answer 11

Plasma - blood without protein or cells (Cloudy)

Serum - plasma minus the clotting factors (clear)

Buffy coat - WBC layer (white)

Question 12

What are platelets, mast cells, basophils, eosinophils, neutrophils and monocytes?

Answer 12

Platelet: clotting cells

Mast / Basophils: inflammation / allergy

Eosinphil: Fungal/ parasitic infection

Neutrophil/ Monocyte/ Macrophage: Phagocytosis

Question 13

WHat are characteristics of neutrophils?

Answer 13

Most abundant WBC - 55-95%

Filled with digestive granules

Eats invading microbes

Has multiple nuclei - visible when stained

Question 14

How do WBCs recognize foreign cells?

Answer 14

WBCs “feel” the surface of every cell they encounter using pattern recognition receptors

PRPs recognize abnormal proteins on foreign cells aka Pathogen associated molecular patterns

Question 15

What are the special pattern recognition receptors on phagocytes?

Answer 15

Toll-like receptors

Question 16

What is the process of phagocytosis?

Answer 16

1. Pattern recognitions receptors recognize pathogen associated molecular patterns 2. Phagocytic cell engulfs the pathogen 3. A bubble forms around the pathogen = phagosome 4. Lysosome store digestive enzymes and chemicals. Stored in granules. Fuses with phagosomes 5. Fused phagosome + lysosome = phagolysosomes 6. Digestion and nutrient absorption into the celll 7. Water is excreted from the cell via exocytosis

Question 17

How are oxygen dependant intracellular killing mehcanisms different than oxygen independent mechanisms? What are examples of each?

Answer 17

Oxygen dendent - require O2 to form reactice toxic species. Reaction occurs inside granules. ie OH radicals, hydrogen peroxide, hypochlorite. Can cause DNA instability. Oxygen independent mechanism - ie Electrically charged proteins - damage membrane of bacteria, fungi or yeasts Lysozomes - damage cell wall Lactoferrins - compete for iron binding proteases - digest and degrade proteins

Question 18

what are characteristics of thrombocytes?

Answer 18

anucleated, fragment of megakaryote Aggregate to seal up fissures in blood vessels and skin to form clots

Question 19

What is the difference between chemokine and chemotaxis?

Answer 19

Chemokine is an attractive chemical signal to attack other WBCs chemotaxis - movement of WBC along the chemokine gradient

Question 20

What are the characteristics of macrophages?

Answer 20

Can digest more than neutrophils Attracted by chemokine released by neutrophil movement by chemotaxis Somewhat specific Have granules promotes cytokines and inflammation Mature form of monocytes

Question 21

what are characteristics of eosinophils?

Answer 21

Granulocytes targets fungus and parasites that are too large to consume Secretes peroxides, lysozymes and other toxins into the invader release cytokine

Question 22

what are characteristics of mast cell and basophils?

Answer 22

release cytokines stored in granules weakly phagocytic Basophils = circulate. Mast cells - in tissues.

Question 23

What are cytokines? examples?

Answer 23

Large class of chemical messnegers which coordinates vasoactive or chemoactive effects of inflammation

ie Histamine (released immediately after exposure to allergen) prostaglandins (synthesis starts when allergin detected) Cuases inflammation

Question 24

What are classic signs of inflammation?

Answer 24

redness - increased circulation and vasodilation,

warmth - heat from increase blood flow

swelling - fluid in circulation assumulates in tissue

pain - nerve endings stimulated

Question 25

What are vasoactive cytokines?

Answer 25

1. histamines - formed by basophils. Pre-stored in granules Act rapidly 2. Prostaglandin- formed from basophils. Made as needed. Slow acting 3. Serotonin - involved in intestinal movements. Secreted by platelets to induce clotting 4. bradykinin - increase the sensation of pain

Question 26

What are the events of inflammation?

Answer 26

1. **Margination** - WBCs to edge of capillary in areas which have **intercellular adhesion molecules** (ICAMs) expressed 2. **Diapedes** - endothelial cells shrink. Makes opening for WBCs to exit 3. **Chemotaxis** - WBCs are pulled to the site of infection following the cytokine gradient

Question 27

What are examples of chemotactic factors?

Answer 27

**Elements of pathogens or toxin**s: endotoxin, PAMPS **Signals of infection**: platelet activating factor, secreted chemotactic factor

Question 28

What is TNF?

Answer 28

Tumor necrotic factor: Made by mscrophages, B & T cells. Increases chemotaxis (attracts more WBCs to area), phagocytosis (increases tastiness of pathogen) and pyrogen (too much may cause fever)

Question 29

What is interferon?

Answer 29

Made by leukocytes and fibroblasts. Anti-viral or anti-tumors

Question 30

What are the different types of interleukins (1, 6, 8, 12)

Answer 30

1. Macrophages/ epithelial cells - causes vasodilation, B&T cell activation, pyrogen 6. macrophage, B&T cell, fibroblast - B&T cell activation, pyrogen 8. Macrophage / epithelial cells - non pyrogenic, chemotactic 12. macrophage - non pyrogenic, activates NK cells and T helper cells

Question 31

What is a niche?

Answer 31

a compartment with unique properties (ability to survive in a temp, pH or with certian nutrients

Question 32

What are the differences between commensalism, mutualism and parasitism?

Answer 32

Commensalism - organisms that benefits from another without harming the host (normal microbiota, indiginous microflora) Mutalism - two organisms cooperate to both benefit (cows and bacteria to digest grass) Parasitism - one organ benefits at the expense of another

Question 33

What is the process of colonization in a new born?

Answer 33

Baby is sterile until birth until baby comes into contact with microbes during delivery Colonization (90%) within 8-12 hrs

Question 34

What bacteria are related to bottle feeding vs breast milk?

Answer 34

Bottle feeding: coliforms, lactobacilli, enteric streptococci, stapylococcus Breast feeding: bifidobacterium

Question 35

What is the process of colonization?

Answer 35

1. Contact - microbes adhere to the body surface 2. Colonization of microbiota 3. Invasion - erode lines of defense and enters sterile tissue 4. Infection - pathogenic material multiplies in tissues. May causept to become asymptomatic carrier, may allow the defenses to fight off the infection or destruction of tissue occurs

Question 36

What is microbial antagonism?

Answer 36

When "good" microbes defend humans against harmful pathogens

Question 37

What are the differences between pimary pathogens and oppotunistic ones?

Answer 37

Primary - likely cause disease when infecting human with normal immune system Opportunistic - cause disease in immunocompromised pts but not usually healthy ones

Question 38

What is pathogenicity?

Answer 38

The capacity of a microbe to cause disease

Question 39

What stage does pathogenicity generally occur?

Answer 39

During invasion (vibrio cholerae) or infection

Question 40

## Footnote What is the complimentary system? Where is it produced?

Answer 40

## Footnote A complex of proteins which results in a porous membrane of a pathogen. Second line of defense. Inactive proteins are produced in the liver

Question 41

## Footnote What is an acute phase protein?

Answer 41

## Footnote A protein that increases significantly during the early stage of inflammation. Part of a positive feedback loop

Question 42

## Footnote What are the three pathways of the complementary system?

Answer 42

## Footnote 1. Classic pathway - antibodies and proteins combine to activate C3. Rapid and specific 2. Sugar on the surface of pathogen - mannosee binding lectin binds to mannose on pathogen cells. Mannose not found in humans. Nonspecific for bacteria and viruses 3. Alternative - C3 binds to pathogens directly (viruses, bacteria, fungi, viruses) All these pathways activates C3

Question 43

## Footnote what happens when c3 is activated?

Answer 43

## Footnote C3 is broken down into C3a (inflammation) and C3b (phagocytosis) C3b activates C5 C5 is broken down into C5a (inflammation) and C5b (oponisation) C5b is the start point for the formation of a MAC complex

Question 44

## Footnote what is a membrane attack complex and how is it formed?

Answer 44

## Footnote Proteins which create a pore in a pathogen's membrane C5b causes C6, C7 and C8 to bind to the pathogen membrane. induces C( to form a pore through membrane. One pore may not destroy cell, but several will

Question 45

## Footnote what is opsonization and opsonin?

Answer 45

## Footnote Opsonization: enhanced phagocytosis - cell is made more delicious Opsonin- any protein which opsonizes cell (C3b, C5b)

Question 46

## Footnote what properties of complement factors make the complement fixation test possible?

Answer 46

## Footnote Complement factors are destroyed 56 degrees C and antibodies are not

Question 47

## Footnote How can the complement fixation test be used to determine flu strains?

Answer 47

## Footnote 1. Serum from the patient is isolated. It is heated to destroy the compliment proteins; however, the natural antibodies are still intact. A pre-measured amount of compliment factors are added to the blood. 2. Pre-processed sheeb RBCs (sRBCs) have sRBC antibodies on them are added into the pt serum 3. Antigen of question is added to the serum. 4. If the test is positive. The serum will remain red, because the compliment factors have formed complexes with the antibody and antigens. If the test is negative it will be pink because the factors cannot fuse with pts antibodies, and instead form complexes with the sRBC antibodies causing the RBCs to lyse

Question 48

## Footnote What is virulence?

Answer 48

## Footnote the degree of harm caused by a pathogen

Question 49

## Footnote What are virulence factors?

Answer 49

## Footnote intrinsic characteristics of a pathogen which can cause harm

Question 50

## Footnote What is the infectious dose?

Answer 50

## Footnote Minimum number of microbes required to cause illness

Question 51

## Footnote What is lethal dose?

Answer 51

## Footnote the minimal number of microbes to cause death

Question 53

## Footnote what is ecoli O157? ID and VR?

Answer 53

## Footnote infects lower intestine. Pathogenic strains aka food poisoning. Produces tocins to break down gut lining ID: 10 or more cells VF: toxins, rapid growth, ability to enter gut

Question 54

## Footnote what is vibrio cholera? ID and VF?

Answer 54

## Footnote Found in the small intestine and aquatic environments. Produces toxin whichdraws salt and H2O which causes severe diarrhea ID: 10^6 - 10^11 VF: toxins

Question 55

## Footnote ID 50/50

Answer 55

## Footnote Minimum amount of microbe required to infect 50% of the population

Question 56

## Footnote what is LD 50?

Answer 56

## Footnote amount required to kill 50% of a given population

Question 57

## Footnote What are different virulence factors?

Answer 57

Adhesion Immune Evasion - anti-phagocytic factors, physiological, immunocompromised Invasiveness - extracellular enzymes, toxins, invasion factors toxins - endotoxins & exotoxins Nutrient Competition genetic

Question 58

## Footnote What are the differences between bacterial and viral adhesion?

Answer 58

## Footnote Bacteria: capsules - slimy, sticky outer layer (molasses) & fimbrae - sticky hair like structures that stick to almost all surfaces Virus: glycoproteins adsorb to cells because of specific interactions with cellular proteins (aka - receptors) ie HIV specifically adapted to fit Cd4 receptors inside of neutrophils. Hemagglutinin - protein spikes of influenza bind to surface of respiritory tract

Question 59

## Footnote What are evasie anti-phagocytic virulence factors?

Answer 59

## Footnote 1. Capsules - slimy layer prevents phagocytosis by covering PAMPs and making it difficult to eat 2. toxins - offensive defensive technique 3. Leukocidins - toxins that directly kill WBC (type of toxins) 4. Intracellular microbes - hide inside host cells by secreting molecules to make it easier to enter ie TB, Malaria

Question 60

## Footnote How do microbes surpass host physiological barriers?

Answer 60

## Footnote ie hpylori. Uses flagella to burrow into mucosa and releases urease that produces ammonia making the environment basic Urea + H2O + urease = CO2 + Ammonia

Question 61

What are the differences between the development of B & T cells?

Answer 61

B: mature in the bone marrow T: mature in the thymus

Question 62

What are antigen presenting cells?

Answer 62

Cells which display the antigens of phagocytized pathogens on the surface using the MHC II protein complex Neutrophils, macrophages, T & B cells

Question 63

What are antigens?

Answer 63

A specific molecule (protein) which can be used by the immune system to identify a specific pathogen Evokes the production of Ab Substances which bind to lymphocyte receptors

Question 64

What happens when B cells encounter antigens? When T helper cells? Cytotoxic cells?

Answer 64

B-cells - makes antibodies T helper cells - activate B cells or cytotoxic T cells using cytokines Cytotoxic T cells - phagocytize cells

Question 65

What are the different between memory and effector cells? What are examples in B & T cells?

Answer 65

Memory - immunological memory of diseases Memory B cells & Effector B cells (Plasma B cells) Memory T cells & Effector T cells (helped & cytotoxic)

Question 66

What are the jobs of antibodies?

Answer 66

1. Agglutination: Antibodies stick together causing the target to clump 2. Neutralization: Bind to the suface of a pathogen and toxin and prevent it's function 3. Opsonization: make pathogens more likely to be digested 4. Complement activation

Question 67

What is the difference between MHC I and MHC II?

Answer 67

MHC I recognizes changes in genes inside of cells (degraded proteins). Works for all nucleated cells. Detects tumors, intracelllular viruses (HIV) and intracellular microbes (Malaria) and stimulated Tc cells MHC II - antigen presenting cells (neutrophils, macrophages & B cells). Recognizes peptides from phagocytized pathogens and exotoxins. Detect microbes, EC viruses and EC exotoxins. Stimulates Th which may cause Tc or B cell response. Stronger response = more sensitive

Question 68

What are epitopes?

Answer 68

The segment of an antigen which is specifically recognized by lymphocyte receptors (receptor has oposite shape of epitopes) 3D receptor sequence of 4-6 amino acids

Question 69

What are immunogens?

Answer 69

Agents which can provoke and immune response and react with the products of such responses All immunogens are antigens but not all antigens are immunogens

Question 70

When are antigens not immunogens? How can they become immunogens? Whar are examples?

Answer 70

1. When they're too small (haptens). Can be bound to larger molecules to cause immuno response. (sugars, drug metabolites, amino acids) 2. When they are too similar to normal cellular proteins (Streptococcus pyogenes - has cell surface proteins which mimic human proteins) 3. When they have static (unchanging) structures ie lipids or globular proteins 4. When they have a highly repeating structure (starch, glycogen)

Question 71

What don't structures similar to cellular proteins cause an immunologic response? How does S pyogenes take advantage of this?

Answer 71

If T/B cells reacted to structures similar to the body, it could cause an auto-immune reaction S pyogenes has surface proteins similar to human proteins

Question 72

What is cross reactivity?

Answer 72

When the immune system recognizes that a pathogen has proteins similar antigens to human cells, it makes antibodies These antibodies may attack normal cells while trying to attack the pathogen

Question 73

What are the intrinsic and extrinsic factors which determine an antigen's immunogenicity?

Answer 73

Intrinsic 1. Chemical composition 2. Size 3. Complexity 4. Genetic Disparity 5. APC processing Extrinsic 1. Adjuvants

Question 74

What is more immunogenic? Proteins or lipids? Why

Answer 74

Proteins are more immunogenic than carbs. Lipids are not immunogenic All cells have a lipid bi-layer. If lipids were immunogenic, it would cause a mass reaction

Question 75

What is more likely to cause an immunogenic response? Larger or smaller molecules

Answer 75

Larger (100,000 MW)

Question 76

What cell structures are more liekly to cause an immunogenic response?

Answer 76

Linear hydrocarbons are less immunogenic than aromatic ring structures

Question 77

What are hospitals scent free zones?

Answer 77

If patients are hypersensitive, they are more liekly to be hypersensitive to scents because of the aromatic compounds. Avoiding use of any scents can prevent this.

Question 78

What is serum sickness?

Answer 78

Old practice making antibodies involved exposing the horse to botulism toxin. The horse generated antibodies from toxin. Serum from the horse was administered to humans as anti-toxin However, the immune system recognized the serum as foreign antigen, and attacked in the serum. Those injected experiences skin eruptions, fever, joint pain,

Question 79

What is the difference between autograft, isograft, allograft and xenograft? Which is the best to use?

Answer 79

Autograft: from self Isograft - from twin Allograft- from an unrelated person Xenograft- from animal Closer to self is best because the body is less likely to recognize it as foreign

Question 80

What are different methods to have autologous transplants?

Answer 80

1. Umbellical cord blood banking - cord has hematopoetic stem cells 2. Autologous Bone Marrow Transplant - bone marrow harbest during remission and stored, during relapse can receive their own bone marrow 3. Autologous blood transfusion - remove blood a month before surgery, its on hand

Question 81

What are autoantigens and alloantigens?

Answer 81

autoantigens - modification of normal proteins causing stimulation of an autoimmune response which causes normal proteins to be recognized as an antigen alloantigens- antigens derived from other people (MHC I)

Question 82

What are heterophilic antigens?

Answer 82

Two different pathogens with similar antigens which can be mistaken for each other ie syphilis and lupus Cardiolipins are found on the syphilis bacteria. Syphilis is tested with anti-cardiolipin Lupus, cardiolipins are auto-antigens therefore if tested with anti-cadiolipins, the antibodiy enters the cell

Question 83

What are adjuvants?

Answer 83

External factors which can make a substance more immunogenic ie - alum (aluminum hydroxide), oil & water emulsion

Question 84

What are immunoglobulins?

Answer 84

Specialized receptors on the surface of B & T cells

Question 85

What is VJD recombination?

Answer 85

Formation of unique immunoglobuins by the random selection of variable, diverse and joining genes. The combinations are all different New clones

Question 86

What is the difference between active naturally acquired immunity and artificially? Passive naturally acquired and artificial?

Answer 86

Active - the body is exposed to an immunogen that stimulates the immune system. Stimulates memory * Natural - body exposed to pathogen * Artificial - exposure after vaccine Passive - individual receives protective immune products but doesn't retain the memory after products cease * Natural - breast feeding or placenta * Artificial- premade antibodies in serum

Question 87

What are the different sources which antigens are produced

Answer 87

1. Inactivated/ Killed pathogen 2. Attenuated pathogen 3. Purified molecules 4. Recombinant protein

Question 88

How are killed/ inactivated pathogens produced? Which vaccines are produced this way? What are pros and cons?

Answer 88

Pathogen is killed by heat, radiation or chemical treatment ie polio, influenza Pros: almost always dead and safe Cons: Does not multiply, higher dose required. May require booster shots, might not be completely dead

Question 89

How are attenuated pathogen produced? Which vaccines are produced this way? What are pros and cons?

Answer 89

Pathogens grown in lab conditions so they aren't as virulent in humans ie - TB, oral polio vaccine Pros - multiplies somewhat, confers long lasting protection Cons - Risk for reversion

Question 90

How are purified molecules produced? Which vaccines are produced this way? What are pros and cons?

Answer 90

Fragments or purified components of pathogens are used rather than living organisms ie anthrax, hepatitis B Pros - no living pathogen Cons - antigen may change shape during purification

Question 91

How are recombinant proteins produced? Which vaccines are produced this way? What are pros and cons?

Answer 91

DNA encoding the protein of a pathogen is expressed in yeast ie - Hepatitis B Pros - cheap, safe Cons - clonal, pathogen can evolve resistance easily (only one protein is represented)

Question 92

What is heard immunity?

Answer 92

Large scale immunization campaign which targers the at risk population. Used to prevent epidemics by estabilshing a high level (over 95% of the people in the population) of immunization

Question 93

What are exoenzymes? what are diseases which cause the following? Mucinase Keratinase collagenase hyalurondiase coagulase

Answer 93

Enzymes secreted by certain pathofens to help disrupt tissues and enter into them further Mucinase - disrupts protective mucous membranes - dysentry Keratinase - ringworm Collagenase - digests connective tissue - clostridium Hyal - digests acid which cemesnts tissue - flesh eating Coagulase - prevents clotting - staphlococci

Question 94

What are different invasive virulence factors?

Answer 94

1. exoenzymes - invades between tight junctions of cell (black plague) 2. Toxins to kill surface endothelium cells - ecoli 3. secretion systems - salmonella

Question 95

## Footnote What are the differences between endotoxins and exotoxins?

Answer 95

Endotoxins are non specific lipopolysaccrides from cell wall. Have systemic inflammation effects but require higher doses for cause. Released from cell wall after lysis ie - meningitis, salmonellosis Exotoins are small proteins which are specific to a cell, and only a small amount can cause reactions. Effects are dependent on which cell is targeted. Secreted from live cells ie - tetanus, anthrax, cholera

Question 96

What are the effects of endotoxins on humans?

Answer 96

Fever, inflammation, shock, hypotension

Question 97

What are the two exceptions of exotoxins which cannot be detroyed by heat?

Answer 97

S. Aureus and B. Cereus emetic

Question 98

What are the two domains of an exotoxin?

Answer 98

Proteins have two domains 1. Binding domain - binds to a receptor 2. Active domain - action of the toxin

Question 99

What are examples of enterotoxins? which bacteria are they produced from?

Answer 99

Ecoli - verotoxin aka s. disenteriae shiga toxin - degrades lining of blood vessels Vibrio Cholera - choleragen toxin - stimulates water secretion into the gut

Question 100

What are examples of neurotoxins? What are their effects?

Answer 100

1. Botulism toxin - flaccid paralysis (numbness, no muscle strength) ## Footnote 2. Tetanospasmin - spastic paralysis (constant contractions)

Question 101

What are examples of hemolytic toxins?

Answer 101

Hemolysins - destroy RBCs ie - streptococcus pyogens (Group A streptococcus) Leukocydins - destroy WBCs Streptococcus aureus - targets neutrophils - necrotizing pneumonia. Can kill patient in 72 hrs

Question 102

What is the difference between blood and chocolate agars?

Answer 102

Blood: agar mixed with nutrient growth mediums and living RBCs. Helps characterize alpha, beta, and gamma bacteria (tests for the presence of hemolysins) Chocolate: for more fussy bacteria which require the nutrients of RBC (iron) to propogate, but cannot get it by itself dt lack of hemolysins

Question 103

What would an alpha, beta and gamma hemolyti bacteria look like on a blood agar?

Answer 103

Alpha: Partial RBC hemolysis, but incomplete digestion. Agar turns green. ie S. viridians Beta: Complete RBC hemolysis. Halo around colonies. ie S. haemolytics Gamma: not hemolytic

Question 104

How is competition with the host for nutrients a virulence factor

Answer 104

By robbing the host of nutrients that it requires to grow, the pathogen can cause harm to the host

Question 105

What is the difference between siderophores and hemoproteins? What are examples of hemoproteins?

Answer 105

Siderophores: bacteria which scavenge free iron from the host. Can dissolve off of hemoproteins Hemoproteins: How a host retains Fe. ie Transferrin, Ferritin, Lactoferrin?

Question 106

Nomenclature difference between hemoproteins and siderophores?

Answer 106

Hemoproteins - ends with "rins Siderophores end in "bactins. ie Mycobaterium = Myctobactin

Question 107

How can genetic defenses be a virulene factor?

Answer 107

Pathogens change their 3D epitope so it doesn't feel the same to the antigen, which means the T cells may not recognize it and antibodies may no longer be efective against it

Question 108

What is variable surface glycoproteins?

Answer 108

A method of pathogens changing their antigen shape by covering the surface with sugars ie - Trypanosome - african sleeping sckness

Question 109

What is the difference between antigenic drift and antigenic shift? WHich is more dangerous?

Answer 109

1. Drift- mistakes in RNA reproduction can help the pathogen evolve- ie Flu virus every year 2. Shift: virus gains foreign genetic material from another species -**genetic reassortment**. Human body cannot recognize the new DNA (HA has changed). Very dangerous. Avian flu (Avian HA is mized with human influenza)