Flashcards in Principles of Immunisation Deck (35):
What are 2 examples of natural passive immunity?
-placental transfer of IgG
-colostral transfer of IgA
What are 2 examples of artificial passive immunity?
-treatment with immunoglobulin
What is human normal immunoglobulin?
contains all antibodies- protein extracted from pooled blood donations
What is human specific immunoglobulin?
selected blood donor with high antibody titres against a specific organism
When is HNIG used for post-exposure prophylaxis?
When are specific immunoglobulins used for post-exposure prophylaxis?
What is an advantage of passive immunity?
gives immediate protection
What are the disadvantages of passive immunity?
-short term: no immunological memory
-graft versus host disease
What is an example of natural active immunity?
What is an example of artificial active immunity?
What are the advantages of active immunisation?
-antigen stimulated immune response
-long term immunity
-faster and better response on second encounter
the administration of antigenic material to stimulate and individual's immune system to develop adaptive immunity to a pathogen
Why might someone not receive a vaccination?
-pregnant woman cannot receive live attenuated vaccines
-immunocompromised cannot be given live attenuated viruses
How does an immune response occur?
-disease causing organism contains antigens
-antigens stimulate the production of antibodies
-antibodies bind to the organism and lead to its destruction and memory B cells are formed
How are live attenuated vaccines made?
attenuation of a pathogenic organism by repeated passage in cell culture or a non-human host
Advantage of live attenuated vaccines
they elicit strong cellular and antibody responses and often confer lifelong immunity with only one or two doses
Disadvantages of live attenuated vaccines
-remote possibility exists that an attenuated microbe could revert to a virulent form and cause disease
How are inactivated vaccines produced?
by killing the disease causing microbe with chemicals, heat or radiation
Advantages of inactivated vaccines
-more stable and safer than live vaccines
-do not require refrigeration
Disadvantages of inactivated vaccines
stimulate a weaker immune system response than liv vaccines
-may require and adjuvant
-boosters likely required
What are 4 examples of inactivated vaccines?
What are acellular vaccines?
use only the antigenic part of the disease causing organism
What are the characteristics of acellular vaccines?
-don't induce the strongest immune response
-may require boosters
-cannot cause disease
When are toxoid vaccine used?
when a bacterial toxin is the main cause of illness- when bacteria secrete toxins or harmful chemicals
How are toxins inactivated?
treating them with formalin
What is an example of a toxoid vaccine?
DTaP (diphtheria, tetanus and pertussis)
What is a BCG?
a vaccine against Mycobacterium bovis to protect against Mycobacterium tuberculosis
What is a subunit vaccine?
-a vaccine that only includes the antigens that best stimulate the immune system
-in some cases they use epitopes- parts of the Ag that Ab or T cells recognise
What is a conjugate vaccine?
A vaccine which links antigens or toxoids from the microbe that an infant's immune system can recognise to polysaccharides
What problem do conjugate vaccines solve?
-many harmful bacteria have an outer coating of polysaccharides
--polysaccharide coatings disguise bacterial antigens so that the immature immune system of infants and children can't recognise or respond to them
What do conjugate vaccines defend against?
How do DNA vaccines work?
-use only genetic material
-when the genes for a microbe's antigens are introduced into the body, some cells will take up that DNA and some cells make the antigen molecules.
-the cells secret the antigens and display them on their surfaces
-this evokes a strong antibody response to the free-floating antigen secreted by cells
-stimulates a strong cellular response against the microbial antigens displayed on cell surfaces
a substance which enhances the body's immune response to an antigen
What is the primary aim of vaccination?
to protect the individual who receives the vaccine