Indiscriminatory Immune System 3 Flashcards
Immune System and Treatment
Immunisation and Vaccination
Single infection usually sufficient to generate protective immunity to a pathogen - prompted practice of variolation against small pox
Two types of immunisation
active immunity: usually permanent, protection produced by persons own immune system
passive: temporary protection that changes with time, protection transferred from another person/ animal
Immunoprophylaxis
Performed before expsoure ( or soon after exposure in certain cases) to an infectious agent to prevent infection
Immunotherapy
performed during active infection ( or existing cancer) intending to cure infection (or cancer)
Features of effective vaccine
- (Safe): must not cause illness or death - low level of toxicity is not acceptable as it will be given to large number of people.
- Protective immunity
- Give long lasting immunity which last for several years - impracticable to give large/ dispersed rural populations regular booster vaccinations - B and T lymphocytes must be primed by the vaccine.
- Induce neutralising antibodies - cheap if they’re administered to large population.
Induce protective T cells
Practical considerations of a vaccine
Low cost - vaccines are the most effective measure in health care but this benefit is eroded as the cost-per-dose rises.
Biological stability
Ease of administration
Few side effects
Other vaccinations/Components - Booster shots
Booster Shots: same vaccine given at a later date (e.g. diphtheria and tetanus toxoids (DT) given every 10 years to refresh the memory cell population
Other vaccinations/Components - Adjuvant
Any substance that enhances the immunogenicity of substances mixed with it.
Differ from protein carriers in that they do not form stable linkages with the immunogen.
Safety and efficacy of replicating (live attenuated) and non-replicating vaccine approaches
live-attenuated viruses are some of the most effacious (e.g small pox) but have the most risk as they are replication-competent. non-replication competent viruses considered to be safer.
examples of live-attenuated viruses
measles, mumps, and rubella vaccines,
non-replication competent vaccines
hepatitis B (subunit) HPV (virus like particle), inactivated poliovirus vaccine (inactivated virus), numerous AIDS vaccine candiates using non-replicating strategies.
Different vaccine platforms (used for SARS-CoV-2 vaccine)
Inactivated vaccines: contain SARS-CoV-2 thats grown in cell culture and chemically inactivated
Live attenuated vaccines: made of genetically weakened versions of SARS-CoV-2 thats grown inc ell culture
Recombinant spike-protein-based vaccines.
Recombinant RDB-based vaccines
Viral like particles. (VLP): carry no genome but display the spike protein on their surface.
Replication-incompetent vector: vaccines cannot propagate in the cells of the vaccinated individual but express the spike protein within them.
Replication-competent vector: vaccines propagate to some extent in the cells of the vaccinated individual and express the spike protein within them.
Inactivated virus vector vaccines: carry copies of spike protein on their surface but has been chemically inactivated.
DNA vaccines consist of plasmid DNA encoding the spike gene under a mammalian promoter.
RNA vaccines consist of RNA encoding the spike protein and are typically packages in LNPs.
Immunotherapy
Form of therapy targeting the imune system to help infection, allergy, autoimmunity and cancer
Uses of immunotherapy
-Inhibit unwanted or excessive immune response-allergy & autoimmunity
-Enhance immune responses-cancer
-Switch off immune undesired responses-transplantation
Immune cel
Immune cells within tumours predict overall survival. T-cell infiltration within tumours predict overal survival in multiple cancer types..?
Chimeric Antigen Receptor (used in adoptive t cell therapy?)
CAR made of antigen binding domain of BCR and signalling domain of the TCR.
A Viral vector used to transfect T cells with CAR gene.
CAR expressed on the surface of T cells after successful transduction.
Process of Adoptive T cell therapy
- Leukocytes are generally collected by leukapheresis and lymphocytes can be enriched by counterflow centrifugal elutriation or subsets selected.
- Enriched lymphocytes placed into culture and stimulated with bead-based artificial antigen presenting cells and viral vector added.
- Culture is expanded in a bioreactor for several days
T cell bulk product is washed and concentrated,
samples removed for quality control release testing and quality assurance review. - Final formulation is cryopreserved allowing facile shipment to distant infusion sites
- Final product bag is thawed and infused.
- Manufacturing time is generally 5 to 10 days, and collection to infusion times can range from 2 to 4 weeks depending on patient clinical status and chemotherapy conditioning regimens.
Process of CAR T-cell manufacturing(used in adoptive t cell therapy?)
Apheresis: Collect patients white blood cells.
Manufacturing Process: Isolate and activate T cells, Engineer T cells with CAR or T-cell receptor gene, Grow and expand number of T cells.
Infusion: Infuse patient with engineered T cells.
Vein to vein time averaged in 17 days in clinical trials.