Module 5: Vaccines and Translational Immunology Flashcards
Immunological techniques
-ELISA
-flow cytometry
-monoclonal antibodies
ELISA
-bottom of wells coated with antigen specific to antibody you want to measure
-wash
-primary antibody is added and if present will bind to antigens
-wash
-secondary antibody is added and will bind to Fc portion of primary antibodies already present
-wash
-enzyme substrate added to well and produces coloured product if antibodies are present
What does ELISA measure
-coloured reaction product by absorbance
-detects presence of antibodies
Flow cytometry
-laser light is scattered after being passed through stream of cells
-the way the light is scattered is unique to each cell type
What does flow cytometry measure
-used to measure physical properties of a cell or specific antigens in a cell
-can also measure total number of cells in suspension, the type and the overall composition
Clinical application of flow cytometry
-can be used to diagnose cancer by detecting DNA aneuploidy
Monoclonal antibodies
-created in a lab
-immortal cells that produce unlimited quantities of one identical antibody
What do monoclonal antibodies measure
-immunotoxins
-radiolabelled antibodies
Clinical application of monoclonal antibodies
-can be produced for defence against specific diseases and cancer
Types of vaccines
-live attenuated vaccines
-killed-inactivated vaccines
-toxoid vaccines
-subunit vaccines
Live attenuated vaccines
-modified strain of the disease-causing agent which had lost its pathogenic ability
-provides prolonged exposure to disease
-but has a potential to revert to virulent form
Examples of live attenuated vaccines
-smallpox
-oral poliovirus
-measles
Killed-inactivated vaccine
-contains a strain of the disease causing agent that has been inactivated by heat, chemicals or radiation
-safer option because it cannot mutate to virulent form
-but generally requires multiple booster doses
Examples of killed-inactivated vaccines
-rabies
-flu
Toxoid vaccine
-contains an inactivated toxin that is a product of the pathogen
-safe because it is not a living organism that can spread
-may require several doses
Examples of toxoid vaccines
-tetanus
-diphtheria
Subunit vaccine
-contains only a small part or fragment of the disease-causing agent
-safest type and can be used on immunocomprimised, pregnant and elderly people
-usually doesnt give long lasting protection
Examples of the subunit vaccine
-hepatitis B
mRNA vaccines
-most recent vaccine type
mRNA vaccine production
-made in the lab from a DNA template of the virus
-encodes an antigen of the virus and then is administered as a vaccine
mRNA host cell
-once inside the body, mRNA enters host cell and uses host cell machinery to produce spike protein
mRNA APC
-newly formed spike protein exits cell and is recognized by antigen presenting cell
-then displays antigen on surface of the cell
mRNA immune response
-antigen is recognized by T helped cell and initiated immune response
Antiviral medications against COVID
-polymerase inhibitor
-protease inhibitor
Ebola vaccines
-uses glycoproteins from ebola and puts them into live attenuated recombinant vesicular stomatis vaccine (VSV)
Phases of vaccine developement
-lab studies
-preclinical studies
-clinical phase 1
-clinical phase 2
-clinical phase 3
-health canada approval
Challenges with vaccine development
-cost
-cold chain
-continuous monitoring
-gold standard
Challenges with influenza virus development
-neuroaminidase antigen
-haemagglutinin antigen
Neuroaminidase
-surface protein that removes sialic acid from cell surfaces and enables new viral copies to infect spread to other cells
Haemagglutinin antigen
-binds to sialic acid on cell surface glycoproteins and leads to endocytosis of virus
Cancer cell vs normal cell
-cancer cells do not need specific growth factors and do not respond to stop signals
Tumour
-cancer cells continue to grow until forming abnormal masses of tissue
Cancer immunotherapy
-aimed at enhancing host antitumour immune responses
Benign tumour
-not cancerous
Malignant tumour
-cancerous and can metastasize
Metastasis
-colonization by tumour cells of sites different from primary site of origin
Cancer immunity cycle
-release of cancer cell antigens: indicate that they are not healthy cells and the immune system is able to recognize the antigens
-cells of the immune system capture them and travel to T cells in lymph nodes
-primary activation: T cells are activated and immune response is initiated
-trafficking of T-cells to tumours: activated T cells move through the blood vessels to site of tumour
-infiltration of T cells: invade tumour to attack it
-recognition of cancer cells by T cells: T cells recognize cancer cells because of antigen they had previously released
-T cells initiate a pathway that results in cancer cell death
Immunosurveillance
-tumour cells are identified and kept under control by immune system of healthy individuals
Immunoediting
-elimination
-equilibrium
-escape
Cancer immunoediting phase 1
-elimination: NK cells, cytotoxic T cells and helper T cells recognize and eliminate tumour cell
Cancer immunoediting phase 2
-equilibrium: if not eliminated, they enter a state of equilibrium where cell starts to kill immune system
-can last for a short time or for years
Cancer immunoediting phase 3
-escape: cells are no longer recognized by immune system and can avoid elimination, they can grow uncontrolled and form a tumour
Evasion of immune response by cancer cells mechanisms
-reduced MHC expression
-poor costimulatory molecules
Reduced MHC expression
-cancer cells display low levels of MHC on cell surface so that they cannot be recognized
Poor costimulatory molecules
-tumours lack there so T cells can only be partially activated
Advantages of cancer immunotherapy
-able to attack cancerous cells throughout all organs in body
-allows immune system to target and eliminate cancer cells without damaging healthy cells resulting in fewer side effects
-takes advantage of immunological memory, allowing for possibility of long term protection
-can be applied to almost any types of cancer
Tumour infiltrating lymphocytes (TILs)
-prognostic biomarker in some cancers
-can leave blood stream and migrate to infiltrate tumour under the influence of chemokines
T cell inflamed “hot” tumours
-show higher CD8 TILs and interferon genes
-usually respond well to treatment
T cell non-inflamed “cold” tumours
-lower CD8 TILs and interferon genes
-usually show an inferior response to treatment
Cold tumour treatment
-one could convert cold tumours to hot tumours by stimulating tumour interferon activity
Immunoscore
-measures density/numbers of T cells in the center and at the periphery of the tumour by immunochemistry
Immunoscore application
-can help stratify patients as having high or low risk cancers and aid in developing treatment plans
Immunoscore steps
-separate tumour in central and peripheral regions
-stain for T cells and conduct digital pathology
-assign a score to the tumour to relate it with an associated diagnosis or risk attribution
Hybridoma cell
-perpetual source of antibodies against one antigen
-secrete one identical antibody
Immunohistochemistry
-how you derive immunoscore
VLP (virus like particle) vaccines
-composed of viral structural proteins that structurally resemble human papillomavirus (HPV)
