Infectious disease
Cause about 70 - 80 % of deaths in
many parts of the Third World
This situation was true for much of
the history of the UK, why has this situation changed?
Antigens and antibodies
What is an antigen, give specific
examples
What is an epitope?
What is an antibody?
How do antibodies confer immunity?
Agglutination Antigenic material is bound
together into clumps
Precipitation Complexes of soluble antigen and antibody become
insoluble and precipitates, (eg. tetanus toxoid)
Neutralisation Antibodies bind and cover the toxic sites of the
antigen
Lysis Some antibodies may cause antigen cell membrane rupture.
History
With reference to the case of Edward
Jenner and James Phipps give the following information,
What was the antigen used?
What was the disease James was hoping
to gain protection from?
Was the antigen given to James an immunization,
a vaccination, or inoculation?
Why did the antigen given provide
protection against another disease?
Is cross immunity common in human
immunology?
Types of immunity
List some mechanisms of innate or
non-specific immunity?
What is specific immunity?
Differentiate between active acquired
and passive acquired immunity, what are the consequences for how long the
person will remain immune?
How may a person become actively
immune?
How may a person become passively
immune?
What is active on passive immunity?
What is local immunity?
What is immunological memory?
What do the terms primary and
secondary immune response mean?
What is clonal expansion?
Immune cells
Give 2 cell types which are
phagocytic?
What is phagocytosis?
Name the types of small lymphocytes
Give a role for each of these cell
types
Abnormal immunity
What is Autoimmunity; give some
examples of autoimmune disease
What is self - tolerance and graft
rejection?
Vaccination
Why should vaccines be kept in the
fridge?
How should vaccines be transported?
How long should vaccines be kept for
in the fridge?
Will any fridge do?
Why should there be a maximum /
minimum thermometer?
Types of vaccine
Living (live attenuated)
Eg. OPV, measles, mumps, rubella, BCG
Immunisation usually achieved with a single dose, except
OPV, (presumably some is digested)
Don’t mix, give one at a time, or simultaneously at
different sites, if not given a 3 week gap is required, (include tuberculin
testing as a live vaccine in this context)
Dead -
inactivated organisms
Eg. Bacterial vaccines such as pertussis, wholecell
typhoid, also IPV (inactivated poliomyelitis)
Primary dose followed by boosters
OK to mix
Dead - components of organisms
Eg. influenza, pneumococcal vaccine
Toxoids
Toxins inactivated by formaldehyde
Eg. tetanus, diptheria
Which factors determine the
effectiveness of vaccination?
By which routes may vaccines be given?
Which children are at increased risk
from infectious diseases so should be prioritised for vaccination?
Contraindications and special
precautions
What are the common contraindications
to vaccination?
When should medical advice be sought
prior to vaccination?
In cases of previous febrile
convulsions, what instruction should be given on prevention and management of
the pyrexia?
Which common side effects may occur
after vaccination?
Protracted inconsolable crying may also occur and must
be taken seriously.
There is a 1:24 000 association between MMR and ITP
(idiopathic thrombocytopenic purpura).
Very rare serious neurological reactions, eg.
encephalopathy after pertussis. Other suggested correlations are very low
frequencies include Guillain Barre and arthritis
Previous severe local or systemic reactions are
contraindications for further vaccination.
Where should desensitising
vaccinations be given?
Anaphylaxis
What is anaphylaxis?
How common is anaphylaxis?
How long does it take to present after
vaccination?
What are the clinical features of
anaphylaxis?
How should anaphylaxis be treated?
What is the optimum temperature for
immune system activity?
What are patient group directions?
http://www.doh.gov.uk/greenbook/greenbookpdf/
Infectious disease
Cause about 70 - 80 % of deaths in
many parts of the Third World
This situation was true for much of
the history of the UK, why has this situation changed?
Living conditions
Nutrition
Vaccination
Antibiotics
Antigens and antibodies
What is an antigen, give specific
examples
Any material the body recognises as
foreign, eg bacteria, virus, snake venom
What is an epitope?
The molecular component of the antigen
the body recognises as foreign and tailors the antibody to
What is an antibody?
An immune protein produced in response
to antigenic exposure
How do antibodies confer immunity?
Agglutination
Antigenic material is bound together
into clumps
Precipitation
Complexes of soluble antigen and
antibody become insoluble and precipitates, (eg. tetanus toxin)
Neutralisation
Antibodies bind and cover the toxic
sites of the antigen
Lysis
Some antibodies may cause antigen cell
membrane rupture.
History
With reference to the case of Edward
Jenner and James Phipps give the following information,
What was the antigen used?
Cowpox virus
What was the disease James was hoping
to gain protection from?
Smallpox
Was the antigen given to James an
Immunization, a vaccination, or inoculation?
An inoculation because it consisted of
the actual disease micro-organism
Why did the antigen given provide
protection against another disease?
Fortunately the antibody produced
conferred sufficient cross-immunity to protect James for the separate disease of
smallpox
Is cross immunity common in human
immunology?
No, it only occurs with closely
related antigens, the more closely related the greater the degree of
cross-immunity
Types of immunity
List some mechanisms of innate or
non-specific immunity?
Flushing effect of urine
Lysozyme in saliva and tears
Action of mucus and cilia in
respiratory tract
Acid in stomach
Intact skin and mucous membranes
Competition from normal flora, eg.
gut, vagina
What is specific immunity?
Immunity which is not innate or non-specific
and is acquired after antigenic exposure
Differentiate between active acquired
and passive acquired immunity, what are the consequences for how long the
person will remain immune?
In active immunity the person produces
their own antibodies . In passive they are given antibodies from someone else.
Active immunity may be long lasting, passive immunity only lasts for the
lifetime of the given antibodies.
How may a person become actively immune?
An antigen causes production of an
antibody
Each exposure to an antigen results in
the production of a highly specific
antibody.
By suffering from the condition
By being exposed to an antigen without
suffering from symptoms of a condition
By vaccination
Antigen antibody reaction is part of
the immune response to an antigen
How may a person become passively
immune?
Trans-placental transfer of antibodies
Ingestion of colostrum
Ingestion of mothers milk
Injections of serum containing
antibodies eg Human Normal Immunoglobulin
Injection of purified extracts of
serum eg hyperimmuneglobulin, and antitoxins, (eg for tetanus, rabies, hep B,
botulism)
What is active on passive immunity?
When someone is enjoying passive
immunity they are exposed to the antigen and develop their own active immunity.
They do not suffer from the condition because of the presence of the passive
immunity
What is local immunity?
Immunity in part of the body, eg. in
the gut after OPV (oral polio vaccine), colostrum and milk antibodies have a
similar effect
What is immuniological memory?
An adaptive immune response is very
much more effective when a particular antigen is encountered for the second
time. Memory cells can probably live for several years.
What do the terms primary and secondary
immune response mean?
Primary Relatively slow to develop and immunity only last a few
weeks
Secondary If the same antigen is introduced a second time a greatly
enhanced response occurs, starts sooner, lasts longer and displays greater
levels of activity. If no symptoms occur after a second exposure the individual
is said to be immune. Often some symptoms may be evident giving a very mild
form of the disease.
What is clonal expansion
Specific small groups of small
lympocytes possess the specific receptor for a particular previously
encountered epitope. Antigens therefore `select` the appropriate lymphocytes
which bind to their epitope. This binding seems to cause rapid clonal expansion
of the involved lymphocyte cell line to give a secondary immune response. The
primary and the secondary response gives rise to memory and effector daughter
cell lines, however the effector cells probably only live for a few days.
Immune cells
Give 2 cell types which are
phagocytic?
Neutrophils, monocytes
What is phagocytosis?
Cell eating
Name the types of small lympocytes
B lympocytes, T helpers, T killers, T
suppressers
Give a role for each of these cell
types
Small lymphocytes recognise foreign
material, they can recognise 108 different epitopes
B lympocytes produce antibodies
T killers (cytotoxic cells) attack foreign
material directly using perforin
T helpers stimulate B cells to produce
antibodies
T suppresser cells stop B cells
producing antibodies
Abnormal immunity
What is Autoimmunity, give some
examples of Autoimmune disease
Where the bodies own immune system
attacks the bodies own tissues, eg rheumatoid arthritis, SLE, diabetes mellitus
type1
What is self - tolerance and graft
rejection?
There is a self/non-self recognition
system. Self tissues are not attacked by the immune system, whereas non - self
material is recognised as antigenic due to the presence of foreign epitopes.
Vaccination
Why should vaccines be kept in the
fridge?
Both freezing and warming may denature
the vaccines
Types of vaccine
What types of vaccine exist?
Living (live attenuated)
Eg. OPV, measles, mumps, rubella, BCG
Immunisation usually achieved with a
single dose, except OPV, (presumably some is digested)
Don’t mix, give one at a time, or
simultaneously at different sites, if not given a 3 week gap is required,
(include tuberculin testing as a live vaccine in this context)
Dead -
inactivated organisms
Eg. Bacterial vaccines such as
pertussis, wholecell typhoid, also IPV (inactivated poliomyelitis)
Primary dose followed by boosters
OK to mix
Dead - components of organisms
Eg. influenza, pneumococcal vaccine
Toxoids
Toxins inactivated by formaldehyde
Eg. tetanus, diptheria
Which factors determine the
effectiveness of vaccination?
The antigenic effectiveness of the
vaccine
The genetic makeup of the individual
By which routes may vaccines be given?
S.C.
I.M.
I.D. BCG always also rabies, cholera,
typhoid may be given this way
Which children are at increased risk
from infectious diseases?
People at increased risk should be
vaccinated as priorities
Asthma, chronic lung conditions,
congenital heart disease, Down`s, HIV, small for dates and premature births,
hyposplenism
Contraindications and special
precautions
What are the common contraindications
to vaccination?
Febrile illness
Any active infection, (minor
infections without pyrexia or systemic upset - still vaccinate)
Allergy to antibiotics in the
preservative
No living vaccines in pregnancy
No live vaccines in impaired immune
responsiveness
Always read the provided information
and the green book to check for specific contraindications
Any cases of previous or suspected
adverse reactions to vaccination, local or systemic, eg. extensive redness,
pyrexia of 39.5 ` C within 48 hours of vaccination, anaphylaxis, bronchospasm,
collapse, unresponsiveness, inconsolable screaming, fits, other cerebral
symptoms
When should medical advice be sought
prior to vaccination?
These following cases apply primarily
to administration of live vaccines in patients who are immunocompromised
Steroid therapy or history of steroid
therapy within 3 months - they cause immunosupression
Immunosupressing therapy, (this does
not include replacement corticosteroids)
Malignancy Chemotherapy or generalised
radiotherapy, for 6 months after treatment
Tumours of the reticulo-endothelial
system
Bone marrow transplantation for 6
months
Any cases of immune deficiency
conditions
Allergy to eggs, (influenza, yellow
fever)
In cases of previous febrile
convulsions instruction should be given on prevention and management of the
pyrexia
Which common side effects may occur
after vaccination?
A mild form of the disease
Discomfort at site
Mild fever and malaise
Other reported adverse reactions
include mild self limiting illness, fever, rashes, injection site reactions.
Protracted inconsolable crying may
also occur and must be taken seriously.
There is a 1:24 000 association
between MMR and ITP (idiopathic thrombocytopenic purpura).
Very rare serious neurological
reactions, eg encephalopathy after pertussis. Other suggested correlations are
very low frequencies include Guillain Barre and arthritis
Previous severe local or systemic
reactions are contraindications for further vaccination.
Where should desensitising
vaccinations be given?
Only in hospital, preferably in or
near a unit with full resuscitation facilities
Anaphylaxis
What is anaphylaxis?
How common is anaphylaxis?
1978 - 89 118 reported
cases from 25 million childhood vaccinations , no deaths
June 92 - June 55 87 cases from 55 million supplied doses
of vaccine, no deaths
How long does it take to present after
vaccination?
What are the clinical features of
anaphylaxis?
How should anaphylaxis be treated?
Information for these answers should
be taken from the learning pack on anaphylaxis
Last question
What is the optimum temperature for
immune system activity?
Probably 38.0`C or even higher.
Homework
Reading Immunisation against
infectious disease, (1996) HMSO up to page 47 is essential. Also read the
relevant pages for every type of vaccine you give, or give advice on
Immune biochemistry
Acute phase proteins
Increase in concentration during
infection by as much as 100 times
Concentrations may be monitored to
chart the progress of an infection
Act as opsonins
Opsonins
Specialised serum proteins
A chemical `tag` that labels a
pathogen for phagocytosis
May be antibodies, acute phase
proteins or complement
Complement
Collective name for about 20 serum
proteins
Some secreted by macrophages
Circulate in inactive form
Activation of first component triggers
off a cascade
Complement may be triggered by
infectious organisms or the labelling chemicals opsonin or antibodies
Final component of cascade is membrane
attack complex
Various intermediate complement
components of the cascade also have functions eg. act as opsonin, attract white
cells, aid in the inflammatory response and stimulate activity of oxidising
agents in macrophages
Membrane attack complex
A cylindrical assembly of molecules
Inserted into the cell walls of
microbes and parasites
Allows sodium and water into the cells