Immune Therapies Flashcards
Why do we manipulate the immune response
To promote protective immune responses - vaccination, fight tumours, treat immunocompromised patients
Suppress unwanted immune responses - chromic inflammation, autoimmunity, allergy
Describe the evolution of an immunisation programme
Stage 1 - prevaccine - disease rates increasing but no vaccine available yet
Stage 2 - vaccine coverage increases and disease starts to decrease
Stage 3 - as disease rates fall, public awareness of disease can decrease and number of adverse events may increase
Stage 4 - resumption of confidence
Stage 5 - eradication
What is the primary aim of vaccination
To stimulate adaptive immunity and generate long-term immunological memory
How does the body respond to first exposure of a pathogen
Early innate immunity will identify non-self antigens and activate inflammation
Cytokines will recruit other innate immune cells to help with response
Dendritic and other APCs will travel to lymph nodes where they will display parts of the pathogen to T and B cells
What happens to T and B cells when first exposed to a pathogen
When the right receptor if found for the antigen, the T or B cell will become active and will proliferate making clones of itself
Activated T cells will become effector T cells and activated B cells will start to make antibodies
How is protective long-term immunity produced
After eradicating the infection, most of the plasma cells and effector T cells will die as they are not required anymore
Small population will remain and survive as long lived memory cells
Some cells will stay in the tissue at the site of infection, some will travel throughout the body via the lymph and bloodstream continually searching for the pathogen
How does the body produce specific antibodies to natural infection
Initially when B cells are activated they produce IgM - low specificity and affinity
Once B cells start communicating with activated T cells, they differentiate into plasma cells, undergoing somatic hypermutation and isotype switching
This allows the plasma cells to start producing the high affinity IgG antibodies which are highly effective at neutralising and clearing the pathogen
Describe the antibody primary response to infection
Low specificity IgM produced first
High specificity IgG takes longer - requires T cell help
Describe the antibody secondary response to infection
More rapid
More effective
High specificity IgG produced by long-lived plasma cells
What are the different types of vaccines
Live attenuated
Inactivated
Subunit (purified antigens)
Viral vector
Describe a live attenuated vaccine
Live but weakened via genetic manipulations
Capable of replication within host cells
Excellent life-long immunity
Potentially pathogenic in immune-compromised
Give examples of live attenuated vaccines
MMR
BCG
Rotavirus
Describe inactivated vaccines
Pathogen killed through chemical or physical process
Cannot replicate or cause disease
Weak immunity
Several doses required
Give examples of inactivated vaccines
Influenza
Polio
Pertussis
Describe subunit (purified antigens) vaccines
No live components - takes protein fragments from the organism that can cause an immune response
Recombinant - produced by genetic engineering
Toxoid - inactivated bacterial toxins
