Vaccine Delivery Flashcards
What is a conventional prophylactic vaccine?
Induction of immunity to a pathogen by injection of a weaken, modified or related form of the pathogen which is no longer pathogenic
Also results in B-cell memory
What are the active ingredients in traditional vaccines?
- Killed organisms or their components
- Attenuated organisms (different organism, culture condition, selection of non-virulent variants)
What are the types of active ingredients in biotechnology-based vaccines?
- Organisms with specific mutations or deletions
- Recombinant protein vaccines
- Recombinant DNA
- Messenger RNA
- Synthetic peptides (used with same epitopes and antigens from the target)
- Plant vaccines (used to stimulate immune system)
What are some future generation vaccine types?
- Therapeutic vaccines
- Tolerogenic vaccines
What is a therapeutic vaccine?
These vaccines are designed to stimulate an immune response in patients who are already infected and has already mounted an immune response to that organism
ex. Cancer, viral diseases, Alzheimer’s disease
What is a tolerogenic vaccine?
These vaccines hope to “calm” the immune system response to self-antigens often targeted in autoimmune diseases or transplanted organs
What are the primary lymphoid organs?
- Bone marrow: B cell maturation
- Thymus: T cell maturation
What are the functions of the primary lymphoid organs?
Provide a site for lymphocytes (B and T cells) to develop from a lymphoid stem cell
What are the secondary lymphoid organs?
- Lymph nodes
- Spleen
- Mucosal lymphoid tissues (lung, gut)
What are the functions of the secondary lymphoid organs?
They are sites where lymphocytes are most active (meeting places for antigens and the immune system)
Briefly explain lymphocyte activation?
- Antigen presentation (APC to T helper cell)
- T helper clonal expansion and maturation (with cytokines released by dendritic cells)
- T helper cells help B cell (humoural immunity) and Cytotoxic T cell (cellular immunity) activation
What is the utility of adjuvants in vaccines?
Antigens alone do not induce a productive immune response
Adjuvants:
- Awaken the adaptive immune system
- Activate antigen presenting cells
- Initiate cytokine secretion
100x the effect for the same amount of antigen, plus reduce risk of actually causing disease because antigen numbers are lower
How do dendritic cells differentiate between non-self and self?
Pathogen-Associated Molecular Patterns (PAMPs) are recognized by dendritic cells on non-self
These non-self molecules are perceived by dendritic cells as molecular signatures of infection
What are the advantages of adjuvant in vaccine formulations?
- Enhance immunogenicity of weak antigens
- Reduce amount of antigen or frequency of immunizatons to acheive immunity
- Improve the efficacy of vaccines
What is the purpose of a vaccine delivery system?
They facillitate transport of antigen to target site
What are some ideal qualities for drug delivery systems?
- Can target dendritic cells
- Can be coupled to dendritic cell maturation agents
- Can accommodate any type of antigen
- Permits intracellular targeting (ability to be phagocytosized)
- Synthetic, stabe, available for global use
What are the advantages of PAMP (TLR ligand) as a vaccine delivery device?
APC binds to PAMP and leads to internalization
The PAMP-antigen allows for improved internalization of antigen and confers protective immunity
What are some types of preventative cancer vaccines?
HPV vaccines (ex. Gardasil, prevention of genital and head cancers)
Hepatitis B vaccine (prevention of liver cancer)
What are some types of therapeutic cancer vaccines?
- Bacillus Calmette-Guerin (BCG) is approved for early-stage bladder cancer
- Sipuleucel T (vaccine composed of patients own stimulated dendritic for prostate cancer)
How does the Stimuvax vaccine work?
It is a liposomal MUC1 (overexpressed in adenocarcinoma cells) cancer vaccine
The MUC1 antigen is inside a liposome system and injected into patient
The antigen enters APC and stimulates formation of specific B and T cells
These MUC1 specific lymphocytes eliminate MUC1+ tumour cells
How were the Pfizer and Moderna COVID-19 vaccines different from the other types?
They were RNA-based vaccines (instructions for spike protein is injected into patients)
