Download Passive vs active & vaccines

2.2.2 Health and Disease
• Compare and contrast the primary and secondary
immune responses;
• Compare and contrast active, passive, natural and artificial
immunity;
• Describe, with the aid of diagrams, the structure of
antibodies;
•
Outline the mode of action of antibodies, with reference to
the neutralisation and agglutination of pathogens;
How immunity develops
• During the body’s first encounter with
a pathogen there will be few
lymphocytes with specific receptors
• It takes time to divide to form clones,
B lymphocytes to secrete antibodies, T
lymphocyte production
• If the same pathogen invades again
persisting memory cells can give a
faster, more effective response
This is ACTIVE IMMUNITY
Secondary
response happens
more quickly, and
produces many
more antibodies
Natural immunity: active and passive
• An infection is an example of acquiring natural
immunity. It is called ACTIVE as your body
needs to work to produce the necessary
antibodies
• When a mother breast feeds her baby she
passes antibodies to it. This is a way of
acquiring PASSIVE immunity as it is a way of
gaining antibodies without the immune system
having to produce them. The thick, yellowish
milk (colostrum) that is produced for the first few
days after birth is particularly rich in antibodies.
Artificial immunity: active and passive
• An alternative to natural
immunity developing is to give
vaccinations (artificial immunity)
• Antigen is injected into the body.
This may be in the form of an
inactivated bacterial toxin or
attenuated (not harmful) virus
which would promote ACTIVE
immunity;
• or the injection of antibodies or
antitoxins which would promote
PASSIVE immunity
(eg Clostridium tetani)
Passive immunity
• Passive immunity doesn’t last as long as
active immunity (only weeks or months):
• No lymphocytes are stimulated to clone
themselves
• No memory cells have been made
• This type of immunity can only last as long
as the antibodies/toxins last in the blood
Antibodies
•Antigen binds with
variable region (specific)
•Have disulphide bonds
between different chains
of the antibody
•Also known as
“immunoglobulins”
shortened to Ig such as
IgA or IgE
•Different
immunoglobulins respond
to antigens in different
ways…
Antibodies
• Neutralisation: bind with
bacterial toxins
• Agglutination: make
pathogen clump together
• Phagocytosis: often follows
agglutination
2.2.2 Health and Disease
• Explain how vaccination can control disease
•
Discuss the responses of governments and other
organisations to the threat of new strains of influenza each
year
• Outline possible new sources of medicines, with reference
to microorganisms and plants and the need to maintain
biodiversity
2.2.2 Health and Disease
• Compare and contrast the primary and secondary
immune responses;
• Compare and contrast active, passive, natural and artificial
immunity;
• Describe, with the aid of diagrams, the structure of
antibodies;
•
Outline the mode of action of antibodies, with reference to
the neutralisation and agglutination of pathogens;
How immunity develops
• During the body’s first encounter with
a pathogen there will be few
lymphocytes with specific receptors
• It takes time to divide to form clones,
B lymphocytes to secrete antibodies, T
lymphocyte production
• If the same pathogen invades again
persisting memory cells can give a
faster, more effective response
This is ACTIVE IMMUNITY
Secondary
response happens
more quickly, and
produces many
more antibodies
Natural immunity: active and passive
• An infection is an example of acquiring natural
immunity. It is called ACTIVE as your body
needs to work to produce the necessary
antibodies
• When a mother breast feeds her baby she
passes antibodies to it. This is a way of
acquiring PASSIVE immunity as it is a way of
gaining antibodies without the immune system
having to produce them. The thick, yellowish
milk (colostrum) that is produced for the first few
days after birth is particularly rich in antibodies.
Artificial immunity: active and passive
• An alternative to natural
immunity developing is to give
vaccinations (artificial immunity)
• Antigen is injected into the body.
This may be in the form of an
inactivated bacterial toxin or
attenuated (not harmful) virus
which would promote ACTIVE
immunity;
• or the injection of antibodies or
antitoxins which would promote
PASSIVE immunity
(eg Clostridium tetani)
Passive immunity
• Passive immunity doesn’t last as long as
active immunity (only weeks or months):
• No lymphocytes are stimulated to clone
themselves
• No memory cells have been made
• This type of immunity can only last as long
as the antibodies/toxins last in the blood
Antibodies
•Antigen binds with
variable region (specific)
•Have disulphide bonds
between different chains
of the antibody
•Also known as
“immunoglobulins”
shortened to Ig such as
IgA or IgE
•Different
immunoglobulins respond
to antigens in different
ways…
Antibodies
• Neutralisation: bind with
bacterial toxins
• Agglutination: make
pathogen clump together
• Phagocytosis: often follows
agglutination
2.2.2 Health and Disease
• Explain how vaccination can control disease
•
Discuss the responses of governments and other
organisations to the threat of new strains of influenza each
year
• Outline possible new sources of medicines, with reference
to microorganisms and plants and the need to maintain
biodiversity
Vaccinations
• Most vaccinations given by injection
eg meningitis C, BCG, MMR
• Some oral eg Polio
• Most contain attenuated virus or bacterial
toxins and offer artificial active immunity
Herd immunity: At least 80-85% of the
population need to be vaccinated to
reduce the chance of somebody catching
the disease – even some one who has not
been vaccinated- to safe levels.
Vaccinations
The MMR controversy
• Hit the headlines in 1998 that the
combined MMR vaccine showed
possible links with autism
• Later rejected by respected
scientists in 2004 but the damage
had been done
The threat of new disease
• There is a constant threat of new
infectious diseases emerging
TASK: make notes from page 186-8 noting
important dates and events in the tracking
of these diseases:
• SARS: severe acute respiratory syndrome
• New strains of flu (eg H5N1)
Sources of new drugs
• There is a continual need for new
drugs and antibiotics
• Around 7000 prescription drugs in
the UK are derived from 3000 plant
species, many of which are found
in tropical rain forests
• For this reason among others it is
important to preserve the rain
forest’s biodiversity
• There are issues about large drugs
companies making lots of money
from plants discovered and used
for centuries by native tribes
Sources of new drugs
• The study of the use of plants by native
people has become known as “ethnobotany”
• Foxgloves contain a poison called digitalin
which can be used to treat irregular heart
rhythms (cardiac arrhythmias)
• Quinine used to treat malaria was first
discovered in the bark of trees in Peru when
locals were seen using it to treat fever
Vaccinations
• Most vaccinations given by injection
eg meningitis C, BCG, MMR
• Some oral eg Polio
• Most contain attenuated virus or bacterial
toxins and offer artificial active immunity
Herd immunity: At least 80-85% of the
population need to be vaccinated to
reduce the chance of somebody catching
the disease – even some one who has not
been vaccinated- to safe levels.
Vaccinations
The MMR controversy
• Hit the headlines in 1998 that the
combined MMR vaccine showed
possible links with autism
• Later rejected by respected
scientists in 2004 but the damage
had been done
The threat of new disease
• There is a constant threat of new
infectious diseases emerging
TASK: make notes from page 186-8 noting
important dates and events in the tracking
of these diseases:
• SARS: severe acute respiratory syndrome
• New strains of flu (eg H5N1)
Sources of new drugs
• There is a continual need for new
drugs and antibiotics
• Around 7000 prescription drugs in
the UK are derived from 3000 plant
species, many of which are found
in tropical rain forests
• For this reason among others it is
important to preserve the rain
forest’s biodiversity
• There are issues about large drugs
companies making lots of money
from plants discovered and used
for centuries by native tribes
Sources of new drugs
• The study of the use of plants by native
people has become known as “ethnobotany”
• Foxgloves contain a poison called digitalin
which can be used to treat irregular heart
rhythms (cardiac arrhythmias)
• Quinine used to treat malaria was first
discovered in the bark of trees in Peru when
locals were seen using it to treat fever