FINAL EXAM! Flashcards

Question

What is Koch’s First Postulates and its limitations?

Answer 1

1. Suspected pathogen must be found in every case of disease but not in healthy individuals Limitations: - Many pathogens are opportunistic - can also be found in healthy individuals Ex. S. aureus

Answer 2

2. Suspected pathogen can be isolated and grown in pure culture Limitations: Not all pathogens can be grown in pure cultures (Ex. Obligate intracellular bacteria viruses and dental plaque biofilm

Answer 3

3. Healthy subject infected with suspected pathogen must develop same symptoms and signs and disease Limitations: - resident microbiota and subjects own immune system may result in different types and severity of signs and symptoms - not all pathogens van be grown in animal host

Answer 4

4. Identical pathogen must be re-isolated from host Limitation: - Pathogen my mutate, becomes more or less virulent - can be difficult to re-isolate

Answer 5

Ability of microbial to cause disease | Whether it does or doesn’t cause disease

Answer 6

Degree of harm abused | How powerful it is ex. mild cough vs organ failure

Answer 7

Ability to cause infection. 1. Contact and enter host Pathogen present (air, food, water, environment, fomite, animals, human carrier) and enter through portal of entry (skin, mucus membranes (eyes, respiratory tract, Gi tract) and parenteral (breaks in the skin)) 2. Adhere to host tissue Bacterial structures and proteins allow adherence to tissues where bacteria can build biofilms 3. Invade tissue and obtain nutrients Pathogens can stay on surface, enter or pass between cells. Virulence factors help spread through cells/tissues which often causes damage. 4. Replicate and multiply (Causes infection) Infectious can be localized or systemic 5. To repeat cycle, pathogen must also be transmitted to new host Pathogen leaves host via portal exit, (rubbing eyes, pus draining, sneezing/coughing, saliva, mucus, vomit, feces, urine, semen, blood, etc.)

Answer 8

1. Structures (Flagella, fimbriae, LPS/otter membrane, capsule, plasmids) 2. Proteins (adhesions, secretory systems) 3. Enzymes (Hemolysin, proteases) 4. Endotoxin (LPS) 5. Exotoxins (damages issues, cannot be killed by cooking, cannot be reversed or removed)

Answer 9

Good: Vegetative cell is growing (happily growing), larger vegetative cell, asexual reproduction cell division by binary fission, two daughter cells and then the cycle begins. Poor: Vegetative cell is growing (happily growing), growth slows due to poor conditions, cell either dies or some bacteria can sporulate, dormant spore will germinate when in good conditions and will return back to a Vegetative cell that is growing.

Answer 10

Appropriate/Sufficient levels of oxygen, nutrients, water, temperature, and pH.

Answer 11

Need oxygen to grow

Answer 12

Can grow with and without oxygen but prefer oxygen

Answer 13

Can grow in either, no preference.

Answer 14

Grow in environments with very little oxygen

Answer 15

NO OXYGENNN

Answer 16

Exponentially.

Answer 17

Disinfectants and antibiotics that target synthesis of cell wall, protein, and DNA

Answer 18

Growth slows Bacteria becomes LESS sensitive and MORE resistant to antibiotics Endospores may form If few cells can persist = chronic infection

Answer 19

Asexual reproduction resulting in 2 genetically identical daughter cells. Also known as binary fission.

Answer 20

1. DNA replicates 2. Cell elongates 3. Septum forms 4. Cell partitions 5. Daughter cells separate

Answer 21

In poor conditions. - metabolically inactive or dormant - highly resistant to starvation, heat, drying, freezing, radiation and chemicals - can last for years - can germinate within minutes when conditions are good - Spores are not reproductive, does not increase population.

Answer 22

1. DNA replicates 2. DNA, ribosomes and enzymes are packaged into spore core 3. Spore core is surrounded by layers resistant to heat and chemicals, forms endospores inside cell 4. Endospores released = free spore 5. Remaining cell dies

Answer 23

Bacteria that reproduce sexually and therefore does not result in genetic variation. 1. Mutation 2. Transposition 3. Horizontal gene transfer

Answer 24

- can be helpful or unhelpful to human body - can be induced by radiation or chemicals - can be spontaneous

Answer 25

Transponsons are able to jump to and from chromosomal DNA and plasmid DNA which results in the transfer of genes = information = abilities

Answer 26

The transfer of genes between bacterial cells of the same or different species - occurs w/out cell division (Not reproduction) A. Transformation: (Like eating a dead bird and growing wings) - bacteria absorbed pieces of DNA from environment - DNA environment can be from dying/dead catering or organisms B.Transduction - viruses can transfer DNA from one bacterium to another C. Conjugation (Bacterial sex) - some bacteria can produce pilus and transfer plasmids - plasmids have gens for antibiotic resisntace or toxins - can be transferred to bacteria of different species.

Answer 27

Biofilms - a place where bacteria exists since they are nit free-floating

Answer 28

A complex communities with many different species of microbes embedded in a protective matrix attached to some surface. Fun fact, their is lots of communication, can look like cooperating or fighting.

Answer 29

70% is made up of living and dead organisms, 30% extra cellular matrix. Matrix: - consists of polysaccharides and proteins from saliva, GCF, and bacteria of biofilm. - acts as a food reservoir and glue (adherence)

Answer 30

Protects bacteria from.. 1. Dehydration - sugars in extracellular matrix draw in water 2. For shortages - some bacteria may secret waste products that can be used by other bacteria as nutrients 3. Immune system - extra cellular matrix blocks diffusion/entry of antibiotics and WBC 4. Antimicrobials - extracellular matrix blocks diffusion of antimicrobial molecules - some antibiotic resistant bacteria can secrete enzymes that protect neighbouring bacteria. - bacteria in biofilm take turns being active and quiescent 5. Transient competitors - resident bacteria bind/block receptors for adhesion, use up nutrients and release toxins (Fighting) - bacteria biofilms produce quorum-sensing molecules (allows cells to communicate, cooperate and share food along with to destroy dugs using specific proteins)

Answer 31

- Stability of oral microbiome (symbiosis) is necessary for health, however a disturbance of oral microbiom (dysbiosis) leads to disease.

Answer 32

Healthy: appropriate immune response (inflammation) + symbiotic biofilm. Gingivitis: dysbiotic biofilm (decrease in diversity, increase in Gm- bacteria) appropriate i immune response however continuous inflammation. Periodontitis: Pathogenic biofilm (mostly Gm- bacteria), excessive immune response, inflammation feeds pathogen in self-perpetuating pathogenic cycle.

Answer 33

1. Antibiotics: produced by moles or other bacteria 2. Semi-synthetic antimicrobials: modified naturally occurring antibiotic 3. Synthetic antimicrobials: chemical found to have antimicrobial properties

Answer 34

bactericidal: - kill bacteria - target the cell wall, nuclei acids and the membrane - can be dangerous to patient since death of GM- cells release lots pf LPS (endotoxin (Located within the cell wall) = large immune response) bacteriostatic: - prevents growth of bacteria - targets protein synthesis, metabolic pathways (Ex. Folic acid synthesis) - requires a healthy immune system to finish the job.

Answer 35

- Dose (amount and quantity) - Type of organism - Length of regime - Route of administration - Pathogen load (how much bacteria is in your body)

Answer 36

1. Spectrum of activity: - broad spectrum: drugs work against many Gm+ and Gm- - narrow spectrum: drugs work against certain groups only. 2. Drug safety: - selective toxicity (targets microbe, minimally damages host cells) - few side effects - does not include allergies 3. Administration route: - oral drugs are easier to administer but need to resist digestive by acid and enzymes in stomach. - can also be given by parenteral route (Injection of infusion) - vein = intravenously - muscle = intramuscularly - skin = subcutaneously 4. Drug stability and elimination: - half-life = time requires for half drug to be broken down by liver and eliminated by kidneys 5. Drug interactions and contraindications: - most drugs have some interactions and contraindications

Answer 37

Narrow: - minimize effects of good bacterias - reduce chance of developing resistance Broad: - if organism is unknown - not enough time to find out - before surgery to prevent infection - could be infected by multiple organisms

Answer 38

- to ensure selective toxicity, antibacterial drugs target bacterial structures not present in eukaryotic cells (Cell wall + ribosomes) - growing cells to make new or more cell wall(s), this requires transpepridase enzyme to complete the last step. Transpeptidase forms the peptide cross link that binds the sugar chains into chain link structure

Answer 39

- chemical structure of drugs include beta-lactam ring, thing ring binds and blocks the transpeptidase enzyme which prohibits the cell wall from being build resulting in burst of bacterium.

Answer 40

- (Beta-lactamase is an enzyme that digests beta-lactam rings) - bacteria that make beta-lactamase are resistant to beta-lactum drugs - therefor combination drugs my work better.

Answer 41

- Acellular - 10-100x smaller than bacteria - obligate intracellular parasites (Need host to make nucleus) due to not being able to make their own nuclei acids and proteins and to replicate using hosts organelles - infect every type of organism

Answer 42

- all viruses have a capsid band genetic material | - some contain envelopes and spikes

Answer 43

- protective shell or coat made by repeating protein subunits. - packages and protects the genome and may contain adhesion proteins.

Answer 44

- made up of envelope proteins that help virus invade cell. - once within cell, insert viral proteins into host cell membrane allowing it to steal part of membrane and leave via budding.

Answer 45

- glycoprotein structures sticking out of capsid or envelope. - binds to specific factors on host, therefor derringers species and tissues that virus infects (Tropism) - helps virus attach and enter host cell - contributes to pathogenicity and virulence - can be recognized by specific immune systems cells abd antibiotics, however can change and escape immune system, which increases it virulence

Answer 46

- either DNA or RNA deliver its DNA or RNA genome into the host cell so that the genome can be expressed (transcribed and translated) by the host cell.

Answer 47

1. DNA -> DNA 2. host DNA pol 3. Detects errors and Corey’s mismatch

Answer 48

1. DNA -> DNA 2. Host DNA pol 3. detects errors and corrects mismatch

Answer 49

1. RNA -> RNA 2. Viral RNA pol 3. None = mutation

Answer 50

1. RNA -> DNA -> RNA 2. Viral reverse transcriptase -> host RNA pol 3. Non = mutation

Answer 51

1. Mutations - DNA polymerase proof reading fails - no RNA polymerase proof reading - can’t cause minor changes to genome (viral proteins that immune system can’t recognize resulting in antigenic drift) 2. Reassortment - 2 viral strains can coinfect the same cell, genome mixing during replication assembly, new viral strain created. Can lead to major antigenic shift, pandemics

Answer 52

1. Bacteriophage replication (in bacteria) - Lyric and Lysogenic replication 2. Animal virus replication

Answer 53

1. Attachment - binds to host cell sugars or proteins 2. Penetration - capsid stays outside - injects nucleic acid 3. Replication - makes cell produce viral genes and proteins - host cell DNA degraded 4. Assembly 5. Release (cell bursts) - by cell lysis - naked phases released

Answer 54

1. Attachment - binds to host cell sugars or proteins 2. Penetration - capsid stays outside - injects nucleic acid - INTEGRATION= prophage (new info, new function) - cell division - host cell stressed - phage exits DNA to find new host 3. Replication - makes cell produce viral genes and proteins - host cell DNA degraded 4. Assembly 5. Release (cell bursts) - by cell lysis - naked phases released

Answer 55

The phage could now carry genes for toxins to other bacteria (Transduction)

Answer 56

1. Attachment - via protein-protein interactions 2a) Penetration - by fusion (enveloped only) - or endocytosis 2b) uncoating - breakdown of capsid to release genome 3. Replication 4. Assembly 5. Release - budding or lysis

Answer 57

1. Attachment - via protein-protein interactions 2a) Penetration - by fusion (enveloped only) - or endocytosis 2b) uncoating - breakdown of capsid to release genome - integration (Viral RNA converted to DNA) - cell division - daughter cell carry vital DNA - When host cell is stressed, virus can return to lytic cycle 3. Replication 4. Assembly 5. Release - budding or lysis

Answer 58

1. Productive infection - host cells replicate and release lots of virions, causes ACUTE INFECTION = immune system clears virus, infection done. Ex. Cold and flu viruses. 2. Persistent infection - virus genome stays in host nucleus which can lead to CHRONIC INFECTION = continued release of virus. Without treatment virus count increases. - can lead to LATENT INFECTION = dormant periods alternating with flare ups. - this can lead to CANCER = if virus disrupts cell division control or proofreading genes

Answer 59

1. Prophage interacting will host DNA can disrupt function and can even lead to cancer 2. Replication within the cell degrades hots’ DNA, therefore disrupting cell function. 3. Virus infected cells can create an immune response that not only kills the infected cells but also neighbouring healthy cells. 4. During release, budding and lysis both kill the host cell.

Answer 60

-ethologies agent: SARS-CoV2

Answer 61

(Inhibits and prevents infection) 1. Physical Barriers: - skin = tough, dry, neutrino poor - mucous membranes = traps microbes, ciliated cells sweep away 2. Chemical barriers: - Acid (Sweat and stomach acid) = inhibits bacterial growth + kills - Lysozyme (in mucus, tears, saliva) = dissolved peptidoglycan in bacterial cell wall (GM+) - Definsin peptides (Made by neutrophils) = poke holes in bacterial membrane - mucus (Contains decoy molecules) = can block viruses 3. Resident microbiota - live on tissue but cause no harm, can produce vitamins, take up space, resources, and can release chemicals that prevent growth.

Answer 62

(Deals with infection in early stages) 1. Inflammation 2. Fever 3. Antimicrobial proteins 4. Innate white blood cells

Answer 63

1. Heat 2. Redness 3. Swelling 4. Pain 5. Loss of function

Answer 64

- Basophils, mast and damaged cells release histamine. 1. Local vasodilation: - redness + heat - white blood cells, clotting factors, immune proteins, and nutrients are brought to the tissues faster due to the dilation 2. Capillary Permeability: - swelling (pushes cells apart), pain, loss of function - allows WBC and materials to enter tissues - Edema dilutes toxins - Edema enhances lymphatic capillary uptake of microbes and dead cells

Answer 65

1. Neutrophils + macrophages release inerleukin-1, hypothalamus, increased temperature set point 2. Metabolic activity = faster repair, increased interferon activity, causes liver and spleen to hoard Fe + Zn = less available for microbial reproduction

Answer 66

1. Interferons - secreted by virus infected cells - stimulate neighbouring cells to produce antiviral proteins - activate macrophages and NK cells 2. Complement proteins - many different plasma proteins made by liver, circulate in inactive form. When one compliment protein is activated, all then become activated in a wave.

Answer 67

Activation: 1. Binding to antibodies on surface of bacteria 2. Spontaneous breakdown 3. Binding to sugars on bacterial surface Actions: 1. Inflammation and attract WBC 2. Label bacteria for phagocytosis 3. Form membrane attack complex (MAC) =channel in membranes -> lysis (Makes hole in virus resulting in blowing up)

Answer 68

1. Basophils 2. Eosinophils 3. Neutrophils 4. Natural killer cells 5. Monocytes 6. Dendritic cells

Answer 69

1. Basophils and mast cells secrete histamine which creates inflammation. (Make up 0.5% of WBC) 2. Vasodilation = increased blood flow = redness + heat. = permeability (spaces between cells enlarge) allow materials to enter tissues = edema (WBC, nutrients and repair proteins can help)

Answer 70

1. Produce H2O2 and superoxide (harmful toxins) against parasites. - stimulate basophils - secrete enzyme to limit histamine action

Answer 71

Kill bacteria 3 ways: 1. Phagocytosis: - engulf bacteria into a membrane bag. Granules fuse and kill, lysosomes fuse and digest. (Will day after 1-2 times) - makes of 60% of WBC 2. Oxidative burst: - try to engulf however some H2O2 escapes and can damage the body. 3. Netosis: - neutrophil extracellular traps, neutrophils burst open releasing a sticky DNA that traps the bacteria.

Answer 72

1. Kills own infected cells (cancer) - lymphocyte 2. Patrols for virus-infected cells, cancer cells or other cells lacking or missing MHC 1 - release perforin (pokes holes in cell’s membrane) and granzymes (digests cell) - virus infected cell dies via apoptosis, debris removed by macrophages.

Answer 73

1. Eats microbes, dead neutrophils and damaged cells 2. Detention: - can decider if bacteria has peptidoglycan, LPS or antibodies/compliments - works best wen pathogen is labeled with antibodies - works best if labeled with complement.

Answer 74

1. Link innate and adaptive immunities 2. Phagocytosis (cellular process for ingesting and eliminating particles), mature DC present bacterial antigen, DC travels to lymph node to present antigen to T-helper cells (mature DC present viral antigens to Thelper and Tcytotoxic cells in lymph)

Answer 75

Innate: which an organism is born with adaptive: which an organism acquires following disease exposure

Answer 76

Innate: Responds to common, conserves pathogen markers (LPS, peptidoglycan) Adaptive: 100 million different lymphocytes exist, each with receptor for 1 antigen.

Answer 77

- inflammation - fever - lysozyme, complement, interferon - basophils - neutrophils - macrophages, dendritic cells - eosinophils - NK cells … (ETC)

Answer 78

- T cells - B cells - antibodies

Answer 79

Innate: immediate -> always present and ready, same each time. Adaptive: needs to be activated (take 7-10 days when first time in contact with pathogen): pool of possibilities -> selection -> activation expansion -> effector cells + memory cells produced. - effector cells eliminate pathogen then die, memory cells last for decades. With each exposure, effectiveness of response improves: - hyper mutation and selection creates B cells + antibodies with increased infinity for antigen. Labeling/recognition improves + memory cells are activated faster

Answer 80

Innate: no or few symptoms Adaptive: symptoms occur when innate is unable to cope and adaptive immunity starts ramping up. -recovery occurs when adaptive immunity enhances and innate immune both work to remove pathogen.

Answer 81

The process of establishing the idea that only those cells capable of recognizing an antigen will proliferate, while other cells are selected against. Clonal selection calls both B and T cells. (Leads to adaptive immunity) Occurs in the bone marrow.

Answer 82

1. Random generation: billions of lymphocytes, each wih different specificity. (Hopefully one will fit a pathogen. Could be against self-antigens) 2. Maturation in thymus and brown marrow: involves testing against self-antigens. Self-reactive lymphocytes are killed. - they get killed because Tcells are binding to own antigens. 3. Pool f 100 million different possibilities: only a few lymphocytes of each type are present. 4. Selection: by binding of foreign antigen leads to activation and clonal expansion. - hypermutation in B cells results in even better antigen binding, leads to stronger response next time = adaptive immunity. - effector cells eliminate antigen then die, memory cells last for decades.

Answer 83

Maturation in thymus and bone marrow because (?)

Answer 84

Selection, activations + expansions because provides antigens in a reasonable load? There for antibodies and memory cells can already be created?

Answer 85

Enhance innate response (B-cells, Antibodies and Thelper cells) and deal with intracellular pathogens (Tcytotoxic)

Answer 86

1. Natural active - ex. exposure to virus 2. Artificial active - ex. Immunization 3. Natural passive - ex. Mothers antibodies 4. Artificial passive - ex. Antibodies to snakes venom

Answer 87

- effector CD4 - activate B +Tcytotoxic cells in lymphoid tissue - return to site of infection and increase effectiveness of innate cells - produce memory Thelper cells

Answer 88

- effector CD8 - will return to site of infection and destroy infected or cancerous body cells - bind to MHC 1 + antigen on infected cell, release perforin (Poke holes) -> release granzymes (digestive enzymes) -> apoptosis. Will produce monetary Tcytotoxic cells

Answer 89

- activated B cells = effector B cells = plasma cells) - produce memory B cells - produce highly specific antibodies

Answer 90

Return to site of infection where they will: 1. Neutralize: block pathogens from entering + damaging cells 2. Opsonize: label to help neutrophils, macrophages, dendritic cells and NK cells recognize pathogens 3. Aggregate: clump pathogens for quick removal 4. Activate complement: including inflammation, initiate cell lysis with MAC

Answer 91

present processed antigens, which are derived primarily from exogenous sources, to CD4(+) T-lymphocytes.

Answer 92

- help activate B cells to secrete antibodies and macrophages to destroy ingested microbes, but they also help activate cytotoxic T cells to kill infected target cells by - TCR = binds specific antigen held in MHC protein - CD4 = protein binds MCH ll (protein) on dendritic cells, B cells abd macrophages.

Answer 93

1: MCH ll + antigen - Finds matching Thelper 2: costimulatory protein - activates Thelper, regulate the activation of T cells and the generation of effector T-cell responses. 3: cytokines - tell Thelper cells what’s to do (communicating chemical) 4: vita,mins - tells Thelper where to go

Answer 94

1. Live attenuated (weakened) 2. Inactivated (killed) 3. Subunit + recombinant 4. toxoid 5. mRNA

Answer 95

- attenuated = grown in lab for 30-80 generations till virus can no longer cause disease (weakened) - whole virus = more sited where immune cells can bind, more Ab and memory cells - live virus = can infect cells, stimulate Tcytotoxic response adv: closest to natural infection, stimulate strong long lasting immunity. Dis: cant be used by immunocompromised ppl Dis: can become virulent if circulates to unimmunized ppl Dis: requires refrigeration

Answer 96

- killed, cannot infect cells or cause diseases - will stimulate Ab response, memory Thelper and memory B cells - relies on production of neutralizing Ab to prevent future infection Adv: cannot cause diseases, can be used by immunocompromised ppl Adv: doesn’t require refrigeration Dis: doesn’t stimulate Tcytotoxic or Tc memory cells Dis: doesn’t create long lasting immunity, requires booster shots

Answer 97

- purified parts of antigenic proteins instead of whole microbe - includes an adjuvant to activate dendritic cells, make costimulatory protein (signal 2) - small section of antigen = less Ab, memory Thelper and B cells - relied on production of neutralizing Ab to prevent future infection Adv: cannot cause diseases, can be used by immunocompromised ppl Dis: doesn’t stimulate Tcytotoxic or Tc memory cells Dis: doesn’t create long lasting immunity, requires booster shots

Answer 98

- inactivated bacteria toxins - stimulates Ab response for early neutralization against toxin but not bacteria. - Includes adjuvant - requires booster shot

Answer 99

- laboratory made sequences are given to produce proteins and antigen Adv: doesn’t contain infectious agent, cannot cause infection or diseas Adv: doesn’t require adjuvant to stimulate DC or formaldehyde to kill infectious agent Adv: mRNA is rapidly degraded, cannot combine with DNA or integrate with hosts DNA Adv: can be rapidly produced and modified Dis: some require extreme cold storage Dis: new technology, no long term data

Answer 100

A place where pathogens reside for long periods of time, a place to reside

Answer 101

Something that is contaminated with the pathogen and mechanically transmits it to another host, however it itself is not infected.

Answer 102

And infected individual who can transmit a pathogen to another host.

Answer 103

An individual who is infected and can pass it to another host however does not show any symptoms.

Answer 104

A preferred host for the organism for a parasite where it reaches maturity and may reproduce asexually.

Answer 105

A host that a parasite will reside in for a few parts of its life cycle however will move to another host.

Answer 106

Pathogens transferred mother -> child

Answer 107

Pathogen gets transferred via sex = example

Answer 108

Coughing and sneezing results in transmission of pathogen

Answer 109

Inanimate objects harbour pathogens that you can pick up.

Answer 110

1. Pathogens transmitted through water 2. Pathogens that float in they air 3. Contamination of food with harmful pathogens

Answer 111

1. An animal that transmitted a pathogen from one anti Al to the other w/out being infected 2. Pathogen reproduces W/in a biological vector that transmitted the pathogen form one host to another

Answer 112

1. Disease that spreads from person to person using direct or indirect mechanisms 2. Infectious disease that isn’t spread from person to person

Answer 113

Disease that can spread from one to person to another

Answer 114

1. # of infected people/population | 2. # of dead people / population

Answer 115

Diseases seen sporadically and w/out geographic concentration.

Answer 116

A disease that happens in a short amount of time w/ more cases than expected in a geographic region.

Answer 117

1. The occurrence of disease cases is excess than expected 2. A widespread occurrence of an infectious disease in a community @ a particular time 3. A disease that is prevalent across a whole country or the world.

Answer 118

He cause of the/a disease

Answer 119

The progression of an infectious diseases from person to person directly or indirectly through population of susceptible ppl as one infected person transmits to others via sex or coughing (EX.)

Answer 120

1. Transmission from the source occurs for a brief period that is less than the pathogens incubation period. 2. A mode of disease transmission in which every infected originates from the same source the is produced for longer than incubation period. 3. Mode of transmission where every infection originates from the same source that produced infectious for a period before stopping and starting again.

Answer 121

- B lactic ring blocks transpeptidase enzyme. - inhibits cell wall synthesis - bactericidal

Answer 122

- bind bacterial ribosomes | - block protein synthesis

Answer 123

- interferes with folic acid synthesis | - needed for DNA replication and division.

Answer 124

1. Adjuvant - stimulate dendritic cells -> costimulatory protein -> activate Th 2. Formaldehyde - used to kill viruses and inactivate bacterial toxins during purification 3. Antibiotics - prevent the growth of bacteria when growing viruses 4. Stabilizers - Help viruses withstand the freeze-drying process 5. Preservative - prevent the growth of bacteria and fungus

Answer 125

- 10-15 years 1. Exploratory stage = lab research 2. Pre-clinical stage = test vaccine in-culture and on animals (immune response) 3. Phase 1 vaccine trials = 20-80 healthy adults (immune response) 4. Phase 2 vaccine trials = 100-1000 random ppl (safety, dose, schedule/mode of delivery) 5. Phase 3 vaccine trials = 1000 - 30,000 random ppl (rare side effects, ability to prevent disease and infection)