VACCINESVACCINESWhat They Are What They Are HowHow They They WorkWork

Topics in nanobiotechnologyPh.D. Student: Aleksandra RóżekPh.D. Student: Aleksandra Różek

What Is a Vaccine?What Is a Vaccine?

Traditional vaccines contain either parts of microbes or whole microbes that have been killed or weakened so that they don’t cause the disease.

- take advantage of the body’s to learn how to eliminate almost any disease causing germ, or microbe,

that attacks it.

Immune system takes > 1 week to learn how to fight off an unfamiliar microbe.

Stronger microbes can spread through the body faster than the immune system can fend them off.

VaccineVaccine Benefits Benefits

Naturally acquired immunityNaturally acquired immunity – – immunity produced by immunity produced by antibodies passed from mother to fetus (passive), or by the body’s own antibodies passed from mother to fetus (passive), or by the body’s own antibody and cellular immune response to a disease causing organism antibody and cellular immune response to a disease causing organism (active).(active).

Artificially acquired immunityArtificially acquired immunity – – immunity provided by vaccines, as opposed to naturally acquired immunity, which is acquired from exposure to a disease-causing organism.

Herd immunityimmunity –– the resistance to a particular disease gained the resistance to a particular disease gained by a community when a critical number of people are vaccinated by a community when a critical number of people are vaccinated against that disease.against that disease.

How Vaccines Work?How Vaccines Work?

Immune systemImmune system – – a collection of specialized cells and organs that protect the body a collection of specialized cells and organs that protect the body

against infectious diseases.against infectious diseases.

LymphocytesLymphocytes: T : T CellsCells & B & B CellsCells

Lymphocytes - Lymphocytes - white blood cells that are central to the immune system’s white blood cells that are central to the immune system’s response to foreign microbes.response to foreign microbes.

MacrophagesMacrophages – large and versatile immune cells that devour and – large and versatile immune cells that devour and kill invading microbes and other intruders. kill invading microbes and other intruders.

- stimulate other immune cells by presenting them with small pieces - stimulate other immune cells by presenting them with small pieces of the invaders.of the invaders.

B Cells – white blood cells crucial to the immune defenses. They come from bone marrow and develop into blood cells called plasma cells, which are the B Cells – white blood cells crucial to the immune defenses. They come from bone marrow and develop into blood cells called plasma cells, which are the source of antibodies.source of antibodies.

T Cells – white blood cells that direct or participate in immune defenses.T Cells – white blood cells that direct or participate in immune defenses.

Memory Cells and natural immunityMemory Cells and natural immunity

After body eliminated the disease some of the B cells and T cells are converted into memory cells.

Memory B cells can quickly divide into plasma cells and make more antibody if needed.

Memory T cells can divide and grow into disease-fighting army.

Different Types of VaccinesDifferent Types of VaccinesLive, attenuated vaccineLive, attenuated vacciness

A vaccine made from microbesA vaccine made from microbes

that have been weakened in thethat have been weakened in the

laboratory so that they can’t causelaboratory so that they can’t cause

disease.disease.

Disease:Disease:Measles, mumps, rubella, polioMeasles, mumps, rubella, polio

(Sabin vaccine), yellow fever(Sabin vaccine), yellow fever

Inactivated or „killed” vaccinesInactivated or „killed” vaccinesA vaccine made from a whole viruses or bacteriaA vaccine made from a whole viruses or bacteria

tthat has been inactivated with chemicals or heat.hat has been inactivated with chemicals or heat.

Disease:Disease:Cholera, flu, hepatitis A, JapaneseCholera, flu, hepatitis A, Japanese

eencephalitis, plague, polio (Salk Vaccine), rabiesncephalitis, plague, polio (Salk Vaccine), rabies

Toxoid vaccineToxoid vaccineA vaccine containing a toxoid, used to protectA vaccine containing a toxoid, used to protect

aagainst toxins produced by certain bacteria.gainst toxins produced by certain bacteria.

Disease:Disease:Diphtheria, tetanusDiphtheria, tetanus

Subunit vaccineSubunit vaccinessA vaccine that uses one or more componentsA vaccine that uses one or more components

oof a disease – causing organism, rather thanf a disease – causing organism, rather than

tthe whole, to stimulate an immune responsehe whole, to stimulate an immune response..

Disease:Disease:Hepatitis B, pertussis, pneumonia caused byHepatitis B, pertussis, pneumonia caused by

Streptococcus pneumoniaeStreptococcus pneumoniae

Different Types of VaccinesDifferent Types of VaccinesConjugate vaccinesConjugate vaccines

A vaccine in which proteins that are easily recognizableA vaccine in which proteins that are easily recognizable

to the immune system are linked to the molecules thatto the immune system are linked to the molecules that

form the outer coat of disease – causing bacteria to form the outer coat of disease – causing bacteria to

promote an immune response. Conjugate vaccines are promote an immune response. Conjugate vaccines are

designed primarily for very young children because theirdesigned primarily for very young children because their

immune systems can’t recognize the outer coats of certain immune systems can’t recognize the outer coats of certain

bacteria.bacteria.

Disease:Disease:Haemophilus influenzae type B, pneumoniaHaemophilus influenzae type B, pneumonia

Caused by Streptococcus pneumoniaeCaused by Streptococcus pneumoniae

DNADNA vaccine vaccinessA vaccine that uses a microbe’s genetic material,A vaccine that uses a microbe’s genetic material,

rather than the whole organism or its parts, to stimulaterather than the whole organism or its parts, to stimulate

an immune response.an immune response.

Disease:Disease:In clinical testingIn clinical testing

Recombinat vector vaccinesRecombinat vector vaccinesVaccines that use modified viruses or bacteria to deliverVaccines that use modified viruses or bacteria to deliver

ggenesenes that code for microbial antigens to cells of the body. that code for microbial antigens to cells of the body.

Disease:Disease:In clinical testingIn clinical testing

Produce a strong immune responseProduce a strong immune response

Often give livelong immunity with one or two dosesOften give livelong immunity with one or two doses

Safer and more stable than live vaccinesSafer and more stable than live vaccines

Don’t require refrigeration: more easily stored andDon’t require refrigeration: more easily stored and

transported transported

Teaches the immune system to fight off bacterial Teaches the immune system to fight off bacterial toxinstoxins

Targeted to very specific parts of the microbeTargeted to very specific parts of the microbe

Fewer antigens, so lower chance of adverse reactionsFewer antigens, so lower chance of adverse reactions

Allow infant immune systems to recognize certain Allow infant immune systems to recognize certain bacteriabacteria

Produce a Produce a strongstrong antibody and cellular immune antibody and cellular immune responseresponse

Relatively easy and inexpensive to produceRelatively easy and inexpensive to produce

Closely mimic a natural infection, stimulating a Closely mimic a natural infection, stimulating a strong immune responsestrong immune response

Remote possibility that the live microbe could mutate back to Remote possibility that the live microbe could mutate back to a virulent forma virulent form

Must be refrigerated to stay potentMust be refrigerated to stay potent

Produce a weaker immune response than live vaccinesProduce a weaker immune response than live vaccines

Usually require additional doses, or booster shotsUsually require additional doses, or booster shots

When developing a new vaccine, identifying the best antigens When developing a new vaccine, identifying the best antigens can be difficult and time consumingcan be difficult and time consuming

Still in expertimental stagesStill in expertimental stages

Still in expertimental stagesStill in expertimental stages

AdvantagesAdvantages DisadvantagesDisadvantages

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