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Medical Immunology
Acquired Immunity
Medical Immunology
Harvesting Antibody
Medical Immunology: : Manufacturing Antibody
Monoclonal Antibodies
Medical Immunology: Manufacturing Antibody
Vaccines
Vaccination- The deliberate induction of adaptive immunity to a pathogen by
injecting a vaccine, a dead or attenuated (nonpathogenic) form of the
pathogen.
“Killed” vaccines
* Bacterial
Dead
* Viral
Replication Ability Removed
“Live” attenuated vaccines
* Bacterial
Nonpathogenic types or disabled mutants
* Viral
Reduced ability to replicate in human cells
More potent and risky for immunosuppressed individual
Medical Immunology: Vaccines
Requirements of Vaccines
* Safe
* Induce effective protection in a high proportion of the vaccinated
population
* Long-lived immunological memory
must be conferred
* There should be little or no requirement
for “boosters”
* Cheap
Medical Immunology: Vaccines
An Effective Vaccination Program....
Provides “herd immunity”
By lowering the number of susceptible individuals in a population the natural
reservoir of infected individuals also falls.
Thus the probability of transmission is reduced; even non-vaccinated
individuals enjoy the benefits of a large scale vaccination program.
#*@%!
Medical Immunology: Vaccines
Allergies (Type 1 Hypersensitivity)
Allergy- Disease following a response by the immune system to an
otherwise harmless antigen
Common allergens
* Drugs
* Foods (eg. Tree nuts, shellfish)
* Venoms
* Insect bites
* Pollens
* Dust mites faeces
The antibody produced to respond to these antigens is IgE.
Medical Immunology: Allergies
Allergies
The constant region of the IgE
antibody may bind to surfaces of mast
cells.
When allergens cross-link preformed
IgE that is bound to mast cells
histamine is released.
Histamine causes smooth muscle
contraction and blood vessel dilation.
Medical Immunology: Allergies
Allergy
Mast cells line the body surfaces (inc. blood vessels, connective tissue, lining
of the gut and lungs) as an alert system to local infection.
As a result, an allergic reaction will create different symptoms depending on
the tissue affected.
Medical Immunology: Allergies
Blood Types: ABO
Blood Transfusions: ABO
Units of packed red cells are
made by removing as much
of the plasma as possible
from whole blood units.
Thence, type O individuals
are considered a universal
donor- antibodies have been
removed and no antigen is
present to excite immune
responses in the recipients.
Having both A and B antigen
means that type AB
individuals have no anti-A or
anti-B antibodies. They are
universal recipients.
Blood Transfusions: ABO and Rhesus +/The presence/absence of rhesus factor is marked by +/- respectively.
Transfusions should approach rhess in the same manner as ABO.
Blood Typing: Rhesus Factor
Medical Immunology: Blood Typing
Immunodeficiency: HIV/AIDS
First reported cases 1981
Over 25% of adults infected in Zimbabwe and Botswana
There are actually 2 types; HIV1 and HIV2
Spread to humans from primates
Pssst....wanna try
some HIV1?
...how about
some HIV2?
Medical Immunology: HIV/AIDS
Human Immunodeficiency Virus
Infection occurs after transfer of body fluids via
* infected T helper cells
* as a free virus in blood, semen, vaginal fluid, milk
This includes:
* Sexual intercourse
* Sharing of contaminated needles
* Use of infected blood or blood products
* Pregnancy (25% foetal infection rate)
Medical Immunology: HIV/AIDS
Human Immunodeficiency Virus
HIV is understood to primarily infect and replicate in T helper cells
can also infect macrophages and dendritic cells.
T helper cell concentrations are significantly reduced after initial infection.
T helper cell populations
are partially restored after
an initial adaptive
response.
Afterwards T helper cell
populations will gradually
and persistently decrease.
The destruction of T helper
cells leads to
immunodeficiency.
Medical Immunology: HIV/AIDS
Acquired Immunodeficiency Syndrome (AIDS)
The adaptive immune response controls but does not eradicate HIV.
HIV does not immediately cause AIDS
Most infected individuals
progress towards AIDS
over time and die following
opportunistic infections
and tumours.
Medical Immunology: HIV/AIDS
Tissue & Organ Grafting
Graft rejection involves the destruction of transplanted tissue
I prefer your
head to mine.....
This occurs as an immune
response to antigens on the
grafted tissue.
The tissues of donors and
recipients must closely matched
in order to minimise likelihood of
rejection.
Hmmmm....
...let's swap!!! (no-one
will find out anyway!)
The likelihood of achieving a
close tissue match therefore
increases with greater genetic
similiarity between donor and
recipient.
Medical Immunology: Graft Rejection
Donors and Recipients
There are several major categories of tissue
grafting
Autografts: Donor and recipient are the same
individual (often occurs for skin grafts)
Syngeneic grafts: Donor and recipient are
identical (eg. identical twins)
Allografts: Donor and recipient are individuals
of the same species
Xenografts: Donor and recipient are of
different species
For recipients of allografts and xenografts a
strict regimen of powerful
immunosuppressant drugs is required.
Medical Immunology: Graft Rejection
MHC Matching
MHC markers are constantly presenting both self and non-self peptides
on the membranes of nucleated cells.
Individuals with similar MHC types
are likely to present a similar variety
of peptides.
Thence matching MHC types is an
important part of minimising the
rejection of allografts.
Medical Immunology: Graft Rejection
Autoimmunity
Autoimmune diseases occur when an adaptive immune response is mounted
against self antigens.
Because the antigen is part of the host's own tissues an immune response
does not eradicate the antigen completely; resulting in a sustained immune
response.
This can lead to chronic inflammatory injury to tissues.
Autoimmune disorders usually arise spontaneously and can be triggered by
* infectious agents
* internal immune dysregulation
Medical Immunology: Autoimmunity
Autoimmune Diseases
Common autoimmune diseases include
Rheumatoid arthritis
Insulin dependent diabetes
Multiple Sclerosis
Lupus Erythematosus
Pemphigus vulgaris
Medical Immunology: Autoimmunity