Download Vaccines stimulating immunity

Vaccines
stimulate
immunity
Cary High
Objectives
 Understand
the purpose of a vaccine
 Explain the three lines of natural immunity
 Describe the four types of vaccine
development strategies
 Identify the advances made by the early
vaccines developed in the US
Deadly Childhood Diseases in US
 Were
common in your grandparent’s
childhood.
 Many of them got diseases such as
diphtheria, whooping cough, polio and
small pox. Many of them lost friends to
these diseases
 The ones that got the diseases and
survived developed PERMANENT immunity
Childhood Diseases in the US
 Are


rare today
due to vaccines that activate the IMMUNE
SYSTEM.
This gives the body the ability to fight off the
germs causing the disease
Scientists working on vaccines
 Immunologists
 Molecular
biologists
 Biochemists
 others
Body’s Natural Immunity
IMMUNE SYSTEM: 3 lines of defense
 Barrier defenses
 Internal defenses:


starts with the production of WBCs in the
bone marrow which become specialized
and circulate throughout the body.
They often collect in the lymph nodes
(located in armpits, neck and groin).
 This
is why you have swollen glands when
fighting off a cold.
First Line of Defense
Nonspecific Barriers to Infection
 Skin
 Mucous Membranes
 Cough
 Sneeze
Second Line of Defense
EATER CELLS:
 Macrophages – special WBCs that attacks
invading microorganisms, engulfs it and
breaks it down into pieces.
 This results in a surface-antigen notification
system being sent out to the rest of the
immune system.
Third Line of Defense
SMART CELLS:
 The antigens cause the formation of specific
antibodies by the B-cell lymphocytes
 T-cells support B-cells for rapid enemy antigen
recognition with future exposures (memory T
cells)
Vaccines imitate the invader
and stimulate immune response
 Using
1.
2.
3.
4.
several strategies:
Live “attenuated” viruses / bacterium (too
weak to cause the disease but strong
enough to activate immune response)
Inactivated or killed viruses / bacterium
(microorganism is killed using chemicals but
leave the surface antigen in tact; antigen
recognition stimulates immune system)
Recombinant DNA-based used for viruses
that will not grow in cultured cells
Experimental Vaccines from engineered
viruses and bacteria
Recombinant DNA - based
 Because
these viruses/bacteria do not
grow in cultured cells, it is impossible to
develop live or inactivated vaccines for
them.
 Scientists identify a subunit of the
virus/bacterium and use recombinant
DNA technology to produce vaccine.
 The subunits activate the body’s immune
response, but do not cause the disease.
Recombinant DNA
Experimental Vaccines

Scientists are:




Trying to engineer viruses / bacteria with specific
genes deleted that will stimulate immune response
without causing the disease
They could also carry the antigens for several
diseases, making them a SUPER VACCINE.
Pharming: developing pharmaceutical vaccines in
plants may provide more efficient and safer
vaccine that is more stable for distribution.
They are working creating new antigens that form
antibodies to trigger specific immune response to
cancer.
Early Vaccines
 Small
Pox – in 1776 Edward Jenner
developed a vaccine used an attenuated
virus (cowpox)
 Polio – virus that infected spinal fluid and led
to paralysis; many put on iron lung machines
to breath. In 1950, Jonas Salk discovered an
injectable inactive vaccine. In 1961, Albert
Sabin advanced this by creating an
attenuated vaccine that is delivered orally
Recombinant Vaccines



Hepatitis B – attack the liver and can cause
death. Mild cases improve with in 6 months.
However, 10% of those cases become carriers
and can transmit the disease to others.
This virus refuses to grow in a cultured dish so
scientist engineered the vaccine using
recombinant DNA technology (cloned gene put
into the DNA of a yeast cell).
Hep-B vaccine is the FIRST BIOENGINEERED
VACCINE
Goal of vaccination program
 to

achieve Herd (Community) immunity
When a critical portion of a community is
immunized against a contagious disease,
most members of the community are
protected against that disease because
there is little opportunity for an outbreak. Even
those who are not eligible for certain
vaccines—such as infants, pregnant women,
or immunocompromised individuals—get
some protection because the spread of
contagious disease is contained.
Vaccination schedule: US children
Age
Hep B
Oral Polio
DPT
Heameophilus
2 months
X
X
X
X
4 months
X
X
X
X
6 months
X
X
X
X
12-15
months
X
15-18
months
X
4-6 years
X
14-16
years
X
MMR
X
X
Q/A
1.
2.
If a child gets an infectious disease,
before he gets his routinely scheduled
vaccine, and survives, does he still need
the vaccine?
A nursing home patient is experiencing a
pervasive case of psoriasis on her skin. Is
she more susceptible to an infectious
disease? Why or Why not?
More Q/A
1.
4.
5.
6.
7.
Name the first recombinant DNA vaccine made
available in the US.
What is the difference between a vaccine made
with an attenuated virus and one made with an
inactive virus?
Can you catch the disease from the vaccine (live
or inactive)?
What is the purpose of a vaccine?
What is the purpose of a vaccination program?