AAV, CRISPR Cas9, CAR-T Cell Therapies Flashcards
What was the first successful gene therapy trial using viral vectors treating?
ADA-SCID (adenosine deaminase severe combined immunodeficiency)
What are some of the attractive gene delivery properties of AAV?
It’s non-pathogenic
Able to package and express foreign genes
Transduce dividing and non-dividing cells
Long-term gene expression in some cells
What are the categories of genes which make up the AAV genome?
Replication and packaging
Viral capsid
Why does it matter that there are different AAV serotypes?
They differ in tropism, transduction efficiency, and how they act
What is the significance of helper-free recombination?
It meant that adenovirus didn’t need to be used so there was no purification step required
What is Glybera?
It was a medication used to treat hereditary lipoprotein lipase deficiency which causes severe pancreatitis
Discontinued after 5 years on the market in 2017 because of high cost and little demand
What is Zolgensma?
Medication used to treat SMA by using AAV9 to deliver a functioning copy of the SMN1 gene
What are some drawbacks to the use of AAV therapeutics?
low transduction efficiencies in certain tissues
Packaging capacity is pretty small
Vector toxicity
Presence of pre-existing neutralizing antibodies in patients
What two types of RNA are required by the CRISPR Cas9 system?
Guide RNA both recruits Cas9 (scaffold function) and has a complementary sequence that can bind to the DNA (spacer function)
What was the first use of CRISPR-Cas9 in therapy?
for beta thalassemia by activating the gene for fetal hemoglobin in hematopoietic stem cells
What is the main drawback to the CRISPR system?
It can create mutations elsewhere in the genome known as ‘off-target’ modifications
How was CRISPR discovered?
In bacteria as an adaptive immune system
How can off-target effects be mitigated in CRISPR?
Guide RNA modification and engineering
Improved Cas variants
What are T-cells role in fighting cancer?
Some find and directly kill cancer cells; other recruit other immune cells; some suppress the immune system
Why do T-cells fail at fighting cancer?
Tumor associated antigen expression decrease HLA molecule down regulation Co-stimulation molecule down regulation TCR signaling blocked T-cell activation failed
