Vaccine AdjuvantsjLawrence Prograis, Jr., M. D.

NIAID/NIHNIAID/NIH

Disclaimer: views and opinions in this presentation are those of the speaker and do not represent official NIH/NIAID policy!!

Immunology 101: The Two Branches of the Immune SystemThe Two Branches of the Immune System

Innate immune system Adaptive immune system

- first line of defense: fast response

- second line of defense: delayed activation of antigen-

Schematic, graphical representation of the timing of the innate vs. adaptive immune response

Innate IR

specific effector cells- independent of adaptive immune system but cells

- dependent on the innate immune system: no specific

e re

spon

se

Adaptive IR

Innate IRimmune system, but cells can effectively interact with cells of the adaptive IS

immune system: no specific response without initial activation of the innate IS

ensi

ty o

f the

- responding cells do not remember previous encounter

ith th ti

- responding cells remember previous encounter with the same antigen = immunological

Time after antigen contact

Intewith the same antigen(no memory)

same antigen = immunological memory

p2

How is an Antigen Recognized?

Receptors Encoded as gene segmentsRearrangement necessary

Adaptive ISFixed in genomeRearrangement not necessary

Innate ISProperty

Distribution of receptors

Rearrangement necessary(antibodies, T cell receptors)

ClonalAll cells of a class are distinct

Rearrangement not necessary

Non-clonalAll cells of a class are identicalreceptors

Recognition

All cells of a class are distinct

Unique details of molecular structures(proteins peptides carbohydrates)

All cells of a class are identical

Conserved molecular patterns(LPS LTA l )

Self-Nonself discrimination

(proteins, peptides, carbohydrates)

Imperfect: selected in individual somatic cells

(LPS, LTA, mannans, glycans)

Perfect: selected over (evolutionary) timediscrimination

Action time

cells

Delayed activation of effectors

(evolutionary) time

Immediate activation of effectors

Factors produced effector mechanism

IL-2 (T cell growth factor)Effector cytokines (IL-4, IFN-) tib di d/ t t i it

effectorsCytokines (IL-1, IL-6)Chemokines (IL-8) Cytotoxic effectmechanism antibodies and/or cytotoxicity Cytotoxic effect

What is an Antigen (=Molecular Pattern) for Cells of the Innate IS?

Cells of the Innate IS recognize Pathogen Associated Molecular Patterns (PAMPs):

for Cells of the Innate IS?

(PAMPs):

PAMPs are molecules expressed by microorganismsg

little variations of these molecules among the microorganisms of a given class

Expression is essential for the survival of the microbe

therefore, these molecules cannot be altered by the microbe in an attempt to avoid immune recognition*avoid immune recognition

*Note: there are exceptions some pathogens change PAMPs and remain viable, e.g, H. pylorichange PAMPs and remain viable, e.g, H. pylori flagellin is no longer recognized by TLR5

Vaccines what for?Vaccines – what for?

Do vaccines really work?Do vaccines really work?

If current vaccines work so well, why make new ones?

• The only disease that was eradicated by a vaccine is smallpox! “Wonder Why y y p• For many diseases, there is no (licensed) vaccine

e.g., HIV, malaria,

yMy Parents

Didn’t Give Me Salk Shots?”

(Tom Little, 1957)

• Some of the available vaccines have limited (poor) efficacy, induce insufficient memory

e g BCG (TB-vaccine)e.g., BCG (TB-vaccine)

• Many currently used vaccines require multiple immunizationse g childhood vaccines (DTP – 5 immunizations!) Hepatitise.g., childhood vaccines (DTP 5 immunizations!), Hepatitis

• Some pathogens express variable antigens (substrains) and easily escape vaccine-induced immunity H5:

e.g., influenza – vaccine induced responses are too narrowly focused on variable epitopes requiring new immunization every year!

i t l l i i i t bl de.g., experimental malaria vaccines against some blood-stage antigens have failed in field trials because of presence of other parasite strains

What does it take to make a new vaccine?at does t ta e to a e a e acc e

An overly simplified comparison of:

“Classic” Vaccines• Efficacious

“Modern” Vaccines• Primary requirement is• Efficacious

• Not too dangerousLarge database of

• Primary requirement is SAFETY

• Efficacious• Large database of safety/AE-data

• Not necessarily easy to

• Efficacious • CHEAP (easy to make)• HIGHLY• Not necessarily easy to

make• Not necessarily well

• HIGHLY defined/characterized

Not necessarily well defined

What is an adjuvant?

Th f il bi l d fi h i dj t *

What is an adjuvant?

The futile attempt to unambiguously define the term vaccine adjuvants*:

“Substances that act to accelerate, prolong and /or enhance the antigen-specific immune responses when

added to purified or complex antigens”added to purified or complex antigens”or:

“The immunologist’s dirty little secret”“The immunologist’s dirty little secret” (J. Janeway)

*Note:• In the infectious disease field, adjuvants are “vaccine adjuvants”

I th fi ld th t dj t i f tl d f t d l• In the cancer field, the term adjuvants is frequently used for stand-alone immunotherapeutics/immunomodulators!!

What is the function of an adjuvant in modern vaccines?

• Attenuation limits pathogen replication and innate “emergency” responses (required for strong innate immunity and which promote strong adaptive immunity)immunity and which promote strong adaptive immunity)

• “Shredded” pathogen recombinant vaccines (or subunit) are inefficiently recognized by phagocytesare inefficiently recognized by phagocytes

• Soluble proteins do not enter the MHC I processing thpathway i.e., do not induce CD8 T cells

• “Clean” subunit/recombinant vaccines lack immunostimulatory signals and are degraded very

idl ft i j ti !rapidly after injection!

What is the function of an adjuvant in modern vaccines?Conclusion

• Adjuvants provide innate immune signals = (mimicking an infection) (mimicking an infection)

• Adjuvants help aggregate antigen (= structure!) and prolong exposure of immune system to antigenprolong exposure of immune system to antigen

= (persistence!)

• Adjuvants can help antigens gain access to the MHC I processing system

(i d ti f t t i T ll )= (induction of cytotoxic T cells)• Adjuvants help the immune system recognize more

epitopes on the vaccine antigen(s)epitopes on the vaccine antigen(s)= (epitope spreading)

What adjuvants do we have?What adjuvants do we have?

For animals: Freund’s and other emulsions (Montanide…), LPS/MPL, Alum, liposomes, saponins, TLR-agonists, NLR-agonists, microparticles, viral/bacterial ghosts, chitosan, starch, alginate, acrylic, … etc etc etc

For humans: (US only – clinically approved adjuvants)1) Alum: for almost a century2) AS04: since 2009 (Alum/MPL)

DTP, DTaP, HepA, HepB, pneumococal conjugate2) AS04: since 2009 (Alum/MPL)

HPV vaccine (Cervarix®) only

pneumococal conjugate, Anthrax, Rabies

The History of Adjuvants: Alum!e sto y o dju a ts u

• 1926, Glenny demonstrated the adjuvant activity of l i d tili i l i it t daluminum compounds utilizing an alum-precipitated

diphtheria toxoid

Al (Al i h d id l i h h t ) i• Alum (Aluminum hydroxide, aluminum phosphate, …) is the most commonly used adjuvant, has been given to billions of people!!!billions of people!!!

• Comparatively weak, but very safe• Induces predominant Th2-type immune response• Induces predominant Th2-type immune response

(antibodies, no/very little CD8 T cell response)

The MOA of Adjuvants: How do they do it?e O o dju a ts o do t ey do t

• “Adjuvants” are a very diverse set of molecules, which trigger very diff / hdifferent receptors/pathways

• Most adjuvants have poorly understood mechanisms!!

The MOA of the following two (only clinically approved adjuvants in the US) will be discussed

AlumMPL

Glenny, A.T. BMJ 2, 244–245 (1930).

The MOA of Alum: A never-ending story?e O o u e e e d g sto y

• Depot formation and slow release of antigen: • Original and most enduring hypothesis• Original and most enduring hypothesis• However, most antigen is quickly released from alum after injection!• Excision of injection site does not impact adjuvanticity!!

• Activation of the Complement system activation of macrophages and eosinophiles• Activation of the Complement system, activation of macrophages and eosinophiles• Aggregation of antigen leading to enhanced uptake by phagocytes• Activation of the NALP3 inflammasome (2008)

Model suggests that:1) Alum is phagocytised2) Alum destroys the phagosome 3) This releases the phagosomal protease

cathepsin into the cytoplasm4) C th i ti t th N l 3 i fl4) Cathepsin activates the Nalp3 inflammasome5) The inflammasome cleaves/activates IL1β

inflammation!

So, do we FINALLY understand Alum?

Inflammasome-model had several flaws: Nalp3 KO mice still respond to Alum (effect of knocking out “key” p p ( g y

molecules was partial, depended on readout – ab vs. T cell response)

inflammasome-activation may be secondary effect as

Current (2011) model suggests that:

macrophages die from Alum-stimulation and caspase-activation!!

1) Alum is NOT phagocytised after all (at least not by dendritic cells)2) Alum interacts with the DC membrane and leads to re-arrangement of lipid rafts3) Re arrangement of membrane components may bring membrane bound3) Re-arrangement of membrane components may bring membrane-bound

receptors together and trigger DC activation4) Alum-bound antigen is “handed off” to DC (phagocytized, processed, presented)

The History of Adjuvants: Freund’s Adjuvante sto y o dju a ts eu d s dju a t

• Developed in the 1930s by Jules FreundB d th b ti th t th “b tt ”• Based on the observation that the “butter” a mycobacterial strain produced made it more immunogenicimmunogenic

• “Butter” was subsequently replaced by paraffin oil which worked betterworked better

• Two formulation of the adjuvant were created: complete and incomplete Freund’s Adjuvant

FCA

a d co p ete eu d s dju a t

mineral oil fraction industrial emulsifiers debris of dried M. tuberculosis

Emulsified together with the antigen solution to a cream-like emulsion

Freund’s Adjuvants: Features

Advantages: outstanding humoral and cellular responses! Still considered the gold standard.

Disadvantages: poorly characterized ingredients, extremely irritant therefore unacceptable for humans (incomplete Freund’s

(IFA, FIA) used in clinical trials), Complete Freund’s (CFA, FCA) can only be used once (boost with incomplete p ( , ) y ( p

Freund’s adjuvant) accidental injection of FCA causes painful, slow healing granulomas

Next-generation of Freund’s-like adjuvants: Replacement of the mineral oil with biodegradable (vegetable) oils: adjuvant 65, …

“Other” adjuvants: Where to start??Ot e adju a ts e e to sta tMany (structurally unrelated) molecules have adjuvant function.How do you categorize them??y g

An attempt to group adjuvants:

Antigen delivery systems ImmunopotentiatorsInsoluble aluminum compounds MPL and synthetic derivatesCalcium phosphate MDP and derivativesLiposomes Oligonucleotides (CpG, etc.)Virosomes™ Double-stranded RNA (dsRNA)Virosomes Double stranded RNA (dsRNA)ISCOMS® Alternative pathogen-associated

molecular patterns (PAMPs) (E. coli heat labile enterotoxin (LT); flagellin)labile enterotoxin (LT); flagellin)

Microparticles (e.g., PLG) Saponins (Quils, QS-21)Emulsions (e.g., MF59, Montanides) Small-molecule immune potentiators

( SMIPs) (e g resiquimod [R848])( SMIPs) (e.g., resiquimod [R848])Virus-like particles & viral vectors Cytokines & chemokines

The MOA of MPL: A clear-cut story?e O o c ea cut sto y• LPS (endotoxin) binds to

TLR4, triggers strong

LPS

inflammatory signals• MPL is “de-toxified” LPS

and acts as an adjuvant but LPSwithout the excessive inflammatory (IL1) response

MPL Q: Why does MPL induce a different signaling response MPLwhen binding to the same receptor (TLR4)??

A: TLR4 is only TLR signaling through both MyD88 andA: TLR4 is only TLR signaling through both MyD88 and TRIF adaptor proteins. MPL preferentially triggers TRIF (“beneficial”) signals!

How do we use this information to make better adjuvants?

Saponin-based adjuvantsWhat are saponins?Tensoactive glycosides containing hydrophobic nucleus with triterpenoid

structure plus carbohydrate chains linked to the nucleusstructure plus carbohydrate chains linked to the nucleus. Naturally occurring in plants and marine organismsNatural function: protect against being eaten (bitter!!), protects against

i b d f i t i t ld bl d d i d i tmicrobes and fungi, toxic to cold-blooded organisms and insects.Applications: food additive, dietary supplements, adjuvants

Saponin-adjuvants used in humans (experimental vaccines)QS21 ISCOM

Purified fraction of QuilA, derived from tree bark Induces strong cellular immune responses

Cage-like particles Saponin-cholesterol micelle

Saponin adjuvants used in humans (experimental vaccines)

Induces strong cellular immune responses Used in humans (HIV, cancer, malaria) Problem: hemolytic! (strong binding to cholesterol)

Saponin cholesterol micelle, forms cage-like structures, Safe (no hemolysis!!), effective MOA: ?? (does NOT form a depot!)

Immunostimulatory DNA! Unmethylated CpG dinucleotides are the reason that bacterial

DNA b t t t b t DNA i i ti l t

Immunostimulatory DNA!DNA, but not vertebrate DNA, is immunostimulatory.

Vertebrate DNA has relatively low amounts of unmethylated CpG compared to bacterial DNA.

A CpG-based adjuvant has already been tested in a few vaccines, an alum-adjuvanted Hepatitis B vaccine and a CpG adjuvanted melanoma vaccine.

Microspheres/MicroparticlesObjective: cause aggregation of antigen to 1) Improve uptake by APC2) I i i it f h l

B

2) Increase immunogenicity for humoral responses3) Route exogenous antigen into the MHCI pathway for CTL induction (disruption of

phagosome and release of particle/vaccine into cytoplasm!)

Examples of microparticles: PLGA spheres Lactide and glyoclide * Polyphosphozanes* Beta-glucan Proteinoids Proteinoids

Most commonly used material:Poly(lactide-co-glycolide) (PLG)Poly(lactide co glycolide) (PLG)

Is a synthetic polymer of lactide and glycolide. It is very safe and also the metabolites are well tolerated U d d li t f i d ( L D t) Used as a delivery system for various drugs (e.g., Lupron Depot)

or material for absorbable sutures

Recap: Wh t h ld MODERN Adj t d ?What should MODERN Adjuvants do?

SAFELY enhance vaccine induced immune responses with little/no SAFELY enhance vaccine-induced immune responses with little/no side effects, provide dose sparing

Drive the desired immune response (i.e., response associated with protection against the pathogen which the vaccine is for Strong antibody vs. strong cytotoxic T cell response Th1 vs. Th2 response Th1 vs. Th2 response

Efficacious AND safe in special populations: Newborn Eld l Elderly Immunocompromised patients:

HIV, cancer, transplant, pregnant, … Defined chemical structure, high purity, defined mechanism-of-

action Induce cross strain protection (e g flu!!) Induce cross-strain protection (e.g., flu!!)

A few “must know” adjuvants:A few must-know” adjuvants:

• Saponins (tensoactive adjuvants): QS21, ISCOMp ( j ) ,

• Emulsions: MF59, Montanide, adjuvant 65

• Microspheres: e.g. PLGA

C b h d t I li l d t• Carbohydrates: Inulin, glucans, dextrans, …

• CpG motifs: as oligonucleotides or in DNA vaccinesCpG motifs: as oligonucleotides or in DNA vaccines

“TRIF-only LPS” – the perfect adjuvant?o y S t e pe ect adju a t

Understanding the cellular signaling pathways allows us to “design” a TLR4 agonist with the most desirable adjuvant qualities:TLR4 agonist with the most desirable adjuvant qualities:• Defined signaling pathway• Synthetic (i.e., defined chemical structure/purity)

Selective activation of beneficial (exclusion of undesirable)• Selective activation of beneficial (exclusion of undesirable) signaling pathways

In principle: great idea!! But…..

Some signaling through the “undesirable” MyD88 pathway is also necessary for:g g g y p y y• Full activation of dendritic cells requires both pathways to be stimulated!• MyD88 signal is necessary for establishing/maintaining T cell memory!!• MyD88 signal is involved in supressing generation of Tregy g p g g g• MyD88 signal is involved in negative inflammatory feedback loop (i.e., limit extent of

inflammatory response and therefore side effects!)

Lesson learned: we STILL do not know enough about the signaling pathways triggered by adjuvants (their role in immunogenicity and their complexity)

Squalene (squalane)-based adjuvantsWhat is squalene? Formed by the condensation of 6 activated isoprene units Naturally occuring e g in/on human skin (natural moisterizer but Squalene Naturally occuring, e.g., in/on human skin (natural moisterizer, but

also in skin-care products) Main (industrial) source: shark livers! By itself squalene is not an adjuvant (used as part of the By itself, squalene is not an adjuvant (used as part of the

emulsion) MOA?????

Squalene-based adjuvants used in humans (EU, not US!)MF59 AS03

Application:Application:Fluad® vaccine

Several 100Mio doses

Pandemrix® vaccine

Content:• SqualeneSeveral 100Mio doses

deployed (outside US) • Tocopherol (VitE)• Tween80

Just to be clear……Squalene does/did NOT cause Gulf War Syndrome (non immunized soldiers got sick, tens of millions of immunized Europeans did not…)!Humans immunized with MF59 do not have higher incidence of autoimmune disease!

Sugar-based adjuvants

Various complex carbohydrates from plants and fungi stimulate the immune system

Gamma-inulin (from plant roots of the Compositae family) strong activator of the complement system

“Crystalline” form acts as a potent, but safe adjuvant

C3 activation and thus strong activation of macrophages (originally used to deplete Complement)

often combined with other adjuvant to direct the often combined with other adjuvant to direct the immune response (e.g. Algammulin – gamma-inulin and Alum hydroxide)

induces Th1 and Th2, does not induce IgE as Alum, no toxicity

b t lli d ith Al t f th h can be co-crystallized with Alum to further enhance adjuvanticity (“algammulin”)

Immunostimulatory DNA?Immunostimulatory DNA?How can nucleic acid be immunostimulatory???

Historic observations: DNA vaccine(1) (2)

cloning

T cells

INFLAMMATION NO RESPONSE

Mucosal Adjuvants: D d thi diff t?Do we need something different?

Why deliver a vaccine through the mucosal route?

Easier administration (easiest route = oral immunization)

Reduced adverse effects

Potential for frequent boosting

Local immunization establishes local immunity at sites where many fpathogens establish infection

Requirements for sterility by far not as stringent as for injected vaccines, no sterile needles needed no trained personnel needed for vaccinationsterile needles needed, no trained personnel needed for vaccination

Mucosal delivery of antigens stimulates mucosal and systemic immunity without affecting maternal antibodies

Recently explored delivery option: aerosolized vaccines as nasal sprays

Mucosal Adjuvants: D d thi diff t?Do we need something different?

Mucosal adjuvants

Be able to interact with M cells in the mucosal epithelium (uptake)

Mucosal adjuvants have to….

Stimulate mucosal immune cells

Most potent available mucosal adjuvants to date (mostly animal studies…):

Bacterial toxins of Vibrio cholerae (CT) E coli (heat labile enterotoxin LT) Bacterial toxins of Vibrio cholerae (CT), E.coli (heat labile enterotoxin LT)Too toxic in humans single AA substitute in enzymatic A subunit of LT (used for intranasal immunizations with Flu vaccine in humans tolerated)

PLG microparticles: taken up by M cells! PLG microparticles: taken up by M cells!

recombinant Shigella bacteria

Non-traditional adjuvants: Inhibitors of inhibitors

•Insufficient immunogenicity may be due to premat re sh t do n of imm neto premature shut-down of immune responses• SOCS (Suppressors of cytokine signaling) induced by several cytokinessignaling) induced by several cytokines, participate in negative feedback loop of cytokine/TLR signals (i.e., limit extent/duration of immune response!!)extent/duration of immune response!!)

How do you block inhibitory pathways with a vaccine adjuvant?

Vaccine would have 3 components:1) Antigen2) TLR agonist (TLR3, 4, 7/8)) g ( , , )3) SOCS1-siRNA (plasmid encoded)

A broader definition of Adjuvants: ANYTHING th t h d ti ithat enhances adaptive immune responses…

• Traditionally, adjuvants have been stimulators of innate immunity (inflammation) which indirectly act on adaptive immunityadaptive immunity

• In practical terms the task of a vaccine adjuvant is to• In practical terms, the task of a vaccine adjuvant is to increase T and B cell responses to the vaccine

Th f t th t t di tl l h tTherefore, agents that act directly on lymphocytesare also vaccine adjuvants!

A Molecular Adjuvant That Enhances Costimulation

APC

Inhibition

Example of a direct T cell-adjuvant

APC

+

MHC

TCRCTLA-4

B7

Resolving the Immune

MHC

-

T-cell- CD28

Inactivation/Anergy

Immune Response(Downregulation)

B7

APCNormal pathway

gy

T-cell

+ +TCR

CD28CTLA-4

Blockade of Inhibition

Initiating the

APC

MHCB7Anti-CTLA-4 mab

Initiating the Immune Response(Upregulation)

T-cell

+--

TCR

CD28

CTLA-4

P l d T ll

Addition of anti-CLTA4 blocking T-cell CD28

Continued Activation

Prolonged T cell response

blocking antibody

A Molecular Adjuvant That Enhances BCR Signaling

AgC3d-molecules*

Example of a direct B cell-adjuvant

CD21 (CR2)

CD19+CD22

CD19B-cell +

Chimeric molecule (e.g. HEL-C3d) with 3 copies of C3d induces same ab-titer as 1000x more HEL in FCA.

*

The future of adjuvant (discovery) research

“Traditional” adjuvant research: serendipitous discovery that a naturally occurring substance has adjuvant properties

“Modern” adjuvant research: systematic search for chemical compounds that trigger defined (innate) immune pathways

Lessons for 21st century adjuvant research

• One size does NOT fit all!• One size does NOT fit all!– we need multiple adjuvants for different antigens,

different immunization routes different targetdifferent immunization routes, different target populations

• Formulation is critical!• Formulation is critical!– How the adjuvanted vaccines is prepared affects

efficacy of the vaccine and side effects!efficacy of the vaccine and side effects!

• The pipeline is clogged!f– Takes too long from discovery to licensure!

“Rationale” adjuvant research (receptor/signal pathway analysis etc) will speed up characterizationpathway analysis, etc) will speed up characterization and helps improve safety profile

Safety concernsSa ety co ce s

Possible (and hypothetical) adverse effects of adjuvanted vaccines:

Local acute or chronic inflammation painful abscess, persistent nodules, ulcers or draining lymphadenopathy

M h i f iti (Al *) l i th l i (li k t i d b t bl !) Macrophagic myofascitis (Alum*): myalgias, arthralgias (link to vaccine debatable!), fatigue, very rare neurologic disease

Neurologic disease: HepB, but not HepA vaccine (therefore, reason for side effect cannot be the al m hich is sed for both accines b t the antigen itself!)cannot be the alum which is used for both vaccines, but the antigen itself!)

Itching, swelling of lymph nodes, allergic responses: Alum and other adjuvants

Influenza-like illness with fever

IgE-type immediate hypersensitivity to vaccine antigen, including anaphylaxis

Chemical toxicity to tissues or organs

Induction of hypersensitivity to host tissue, producing autoimmune arthritis, amyloidosis, anterior uveitis

Carcinogenesis, teratogenesis or abortogenesis

* Alum is also found in: food, deodorant, medicines, breast milk and baby formula!!!

g , g g

Fear mongering and misinformation i d kcampaigns do work…

The Vaccine May Be More Dangerous Than Swine Fluy gBy Dr Russell Blaylock

http://socioecohistory.wordpress.com/2009/07/15/dr-russell-blaylock-vaccine may be more dangerous than swine flu/vaccine-may-be-more-dangerous-than-swine-flu/

Animal studies using this adjuvant have found them to be deadly. A study using 14 guinea pigs found that when they were injected with the special adjuvant only one animal survived A repeat of the studythat when they were injected with the special adjuvant, only one animal survived. A repeat of the study found the same deadly outcome.

So, what is this deadly ingredient? It is called squalene, a type of oil. The Chiron company, maker of the deadly anthrax vaccine makes an adjuvant called MF 59 which contains two main ingredients ofdeadly anthrax vaccine, makes an adjuvant called MF-59 which contains two main ingredients of concern-squalene and gp120.

The second ingredient, and one that greatly concerns me, is called gp120, a glycoprotein. Researchers found when it was mixed with squalene, the glycoprotein became strongly antigenic -that is, it produced a powerful and prolonged immune response to the vaccination. In fact, their studies show that with each dose, the intense immune reaction lasts over a year.

Now for the shocker-the glycoprotein-gp120, a major component of MF-59 vaccine adjuvant, is the same protein fragment isolated from HIV - the virus that is responsible for the rapid dementia seen in AIDS patients.

ConclusionConclusion

• Vaccines and vaccine adjuvants may have some (usually mild) side effects and minor ( y )risks,

• But disease has predictable and severe• But, disease has predictable and severe side effects and frequent consequences

/include disability and/or death

Smallpox Polio Tuberculosis Pertussis

Epitope spreading: Example

Data from Dr. Hana Golding, FDA)

What does it take to make a new vaccine?Part B: Making vaccines safer

More virulent

More attenuated

vaccine vaccine

Benefit from/requireadjuvants!!!

Example:DTP: diphteria and tetanus toxoid, whole-cell pertussisDTaP: -”-, acellular pertussis

Acellular is safer, butless immunogenic!!

Example: