Lecture 12 - Cell-based therapies

Question 1

What are some examples of cell-based therapies?

Answer 1

• HSCT
• Mesenchymal stem cells
• Pluripotent stem cell-derived cells
• Engineered tissues and organs
• CAR T cells
• Antigen presenting cells
• Blood cells - RBCs, platelets
• Pancreatic islet cells
• Skin grafts
• Somatic cells, e.g. chondrocytes
• Tissue and organ transplants

Question 2

What are the two types of stem cell therapies?

Answer 2

• Autologous
• Allogeneic

Question 3

Fill in the blank: Cells can be ‘wild type’ or _______.

Answer 3

genetically modified

Question 4

What is the process for cell therapy development?

Answer 4

• Harvest
• Selection
• Amplification
• (Differentiation)
• Screening
• Administration

Question 5

What can pluripotent stem cells (PSCs) be differentiated into?

Answer 5

All other types of cells, including other stem cells

Question 6

True or False: PSCs can be used to generate midbrain dopaminergic neurons.

Answer 6

True

Replaces those lost in Parkinson’s disease

Question 7

What is the FDA-approved gene therapy stem cell treatment for ADA-SCID?

Answer 7

Strimvelis

Question 8

What is the significance of a single nucleotide polymorphism in the β-globin gene for sickle cell disease treatment?

Answer 8

It allows for the transfection of autologous HSCs with an antisickling β-globin gene.

Question 9

Fill in the blank: Engineered HSCs can be used for _______ treatment.

Answer 9

HIV

Question 10

What are cytotoxic T cells (Tc cells) activated by?

Answer 10

Antigen presenting cells such as dendritic cells

Prime Tc cells with specific antigens for target cells, e.g. infected cells, cancers)

Question 11

What do Tc cells release to induce apoptosis in target cells?

Answer 11

• Perforin
• Granzyme

Question 12

What is an emerging approach in cancer immunotherapy involving antigen presenting cells?

Answer 12

Artificial APCs

Decorates cells or microparticles with antigens in order to prime T cells

Question 13

What are CAR T cells genetically engineered to do?

Answer 13

Express a chimeric antigen receptor (CAR)

Related emerging therapies:
* TCR-T cells
* CAR-M
* CAR-NK cells

Question 14

True or False: CAR T cells do not proliferate upon contact with their target antigen.

Answer 14

False

Question 15

What is the main advantage of artificial antigen-presenting cells?

Answer 15

They do not require harvesting from the patient.

Question 16

What is the role of directed differentiation in stem cell therapy?

Answer 16

To replicate specific signaling/contact conditions to guide cell differentiation.

Question 17

What is the outcome of the recent study on sickle cell disease with 35 patients?

Answer 17

High levels of therapeutic antisickling β-globin without recurrence of sickle crises.

Question 18

What is Breyanzi?

Answer 18

Autologous CAR T cells against CD19 for relapsed or refractory large B-cell lymphoma

Approved in Feb 2021 in the USA.

Question 19

What are some ongoing studies related to CAR-T therapies?

Answer 19

Examining different tumour-specific antigens, particularly for solid tumours

Reference to advancements in CAR-T cell applications.

Question 20

What role do iPSCs play in cancer treatment?

Answer 20

iPSCs express a number of tumour-associated antigens and (autologous iPSCs) could act as personalised cancer vaccines

Express tumour-associated antigens when tested against murine tumour models, vaccination with irradiated iPSCs + CpG led to tumour regression.

Treatment possible within a few weeks of diagnosis.

Question 21

What are some challenges in using a patient’s own cells for therapy?

Answer 21

• Cell damage or senescence
• Genetic mutations or disease pathology
• Time constraints
• Insufficient cell numbers
• Immune dysfunction
• Difficulty in culturing or engineering cells
• Comorbidities

Factors that can prevent autologous cell use.

Question 22

What is encapsulated cell therapy?

Answer 22

A strategy where cells are used to manufacture therapeutic proteins in situ when implanted into a patient

Useful for delivering therapeutic proteins for various diseases.

Question 23

What are some therapeutic targets for encapsulated cell therapy?

Answer 23

• Eye diseases
• Neurodegenerative diseases
• Diabetes
• Cancers

Examples of diseases that could benefit from this therapy.

Question 24

What is the significance of the human leukocyte antigen (HLA) complex?

Answer 24

Determines whether the immune system sees cells as self or non-self

Important for understanding transplant rejection.

Question 25

What is the immune compatibility of hPSCs?

Answer 25

hPSCs express HLA class I antigens but not class II and require careful HLA matching ## Footnote They are not universally applicable. When differentiated, HLA class I expression changes.

Question 26

What are hypoimmunogenic iPSCs?

Answer 26

iPSCs that maintain characteristics and can evade immune rejection in mismatched recipients ## Footnote Potential for universal transplantation - CD47 is tumour-associated antigen that is implicated in avoidance of phagocytosis.

Question 27

What is the potential of off-the-shelf cells?

Answer 27

Clonal expansion of engineered iPSCs to generate master cell lines for well-defined treatments ## Footnote A promising avenue for standardized therapies.

Question 28

What is the role of bacteria as therapeutic agents?

Answer 28

Bacteria can colonise hypoxic areas of tumors, which are resistant to traditional therapies ## Footnote Explored as a novel treatment approach. These bacteria classes as obligate anaerobes.

Question 29

What are the challenges associated with cell-based therapies?

Answer 29

* Extremely expensive * Require extensive processing ## Footnote Issues that could limit widespread adoption.

Question 30

Fill in the blank: Autologous iPSCs could act as _______ cancer vaccines.

Answer 30

personalised

Question 31

What are the 7 transcription factors found which are sufficient to generate functional HSCs? ## Footnote Morphogen-directed differentiation of human PSCs into haemogenic endothelium.

Answer 31

1. ERG 1. HOXA5 1. HOXA9 1. HOXA10 1. LCOR 1. RUNX1 1. SPI1

Question 32

How was iPSCs used as a therapy for a patient with Parkinson's disease?

Answer 32

iPSCs reprogrammed into 2.4 million dopamine precursor cells and implanted into dopamine activity centre of the brain

Question 33

What is strimvelis?

Answer 33

It is an autologous CD34+ enriched cell fraction that contains CD34+ cells transducted with retroviral vector that encodes for human ADA cDNA sequence.

Question 34

What does strimvelis treat?

Answer 34

Treatment of SCID due to adenosine deaminase deficiency (ADA) in patients who cannot be treated by bone marrow transplant as they do not have suitable donor.

Question 35

How does strimvelis gene therapy work?

Answer 35

1. Patient bone marrow collected 1. CD34+ cells isolated and stimulated with cytokines (SCF, Flt3, TPO, IL-3) 1. Three daily rounds of retroviral supernatant addition inserted into CD34+ cells with ADA gene 1. Transduced CD34+ cells infused into patient

Question 36

What is the Lyfgenia cell-based therapy? ## Footnote First FDA approved gene therapy for patients with sickle cell

Answer 36

Lyfgenia uses a lentiviral vector to genetically modify CD34+ HSCs to produce HbAT87Q, which functions similarly to haemoglobin A. RBCs with HbAT87Q have a lower risk of sickling and occluding blood flow. These modified cells are then delivered to the pateint. ## Footnote Major side effect - haemotologic malignancy

Question 37

What is the single nucleotide polymorphism associated with sickle cell disease?

Answer 37

SNP is A to T change in the beta-goblin gene which results in formation of haemoglobin S

Question 38

What is the Casgevy cell-based therapy? ## Footnote Casgevy is the first FDA-approved therapy utilising CRISPR/Cas9

Answer 38

HSCs edited using CRISPR/Cas9 to modifiy the BCL11A gene whcih regulates haemoglobin production, allowing more HbF production. Edited HSCs transplanted back to patient.

Question 39

Why is the BCL11A gene targeted in Casgevy therapy?

Answer 39

BCL11A normally prevents the body from producing HbF after birth. By disrupting BCL11A, Casgevy aims to reactivate the production of HbF in patients with sickle cell disease and prevent sickling of RBCs.

Question 40

How does Casgevy target BCL11A?

Answer 40

Targets its ethryoid-specific enhancer region to reduce inhibitory effect on fetal haemoglobin.

Question 41

What is the principle behind using HSC-based therapy to treat HIV?

Answer 41

HSCs can be used to regenerate an HIV-resistant immune system by modifying or replacing them with cells lacking the CCR5 receptor. HIV requires CD4 as receptor and CCR5 as co-receptor to infect CD4+ T-cells. Without CCR5, HIV blocked entry.

Question 42

What is the 'Berlin Patient' Case?

Answer 42

A HIV-positive man with acute myeloid leukemia (AML) was cured after receiving a stem cell transplant from a donor with the CCR5Δ32 mutation, making his immune cells resistant to HIV.

Question 43

What CAR-T cell therapy was used to treat diffuse large B-cell lymphoma (DLBCL) of CNS relapse?

Answer 43

Anti-CD19 CAR-T cell therapy plus BTK inhibitor and PD-1 antibody (BTK enhance function and implantation of CAR-T cells and PD-1 promote their anti-cancer activity). ## Footnote Approved CD19-targeted CAR-T therapies are Yescarta, Kymriah, Brexstrum.

Question 44

What did the CAR-T cell for DLBCL target?

Answer 44

In CD19-targeted CAR-T therapy, CAR is designed to recognise CD19 (protein on surface of B cells) and T-cells can kill B cells.

Question 45

What is Encelto and what does it treat?

Answer 45

Encelto is an allogenic encapsulated cell therapy for treatment of idiopathic macular telangiectasia type 2 (MacTel). MacTel affects Muller cells and cannot maintain blood-retinal barrier (support photoreceptors) disrupts the blood supply to the retina, leading to the loss of photoreceptors.

Question 46

How does Encelto work?

Answer 46

A semi-permeable capsule containing genetically engineered allogeneic retinal pigment epithelium cells which express recombinant human ciliary neurotrophic factor is implanted into vitreous cavity of the eye to slow down loss of photoreceptors.

Question 47

How are hypoimmunogenic induced pluripotent stem cells (iPSCs) generated?

Answer 47

By CRISPR/Cas9-mediated knockout of HLA‐A, HLA‐B, and the class II transactivator gene (CIITA) to remove major T-cell targets, combined with transgenic expression of immune-inhibitory molecules (e.g., CD47 signal and HLA-E) to prevent NK-cell attack - creating iPSCs that evade both adaptive and innate immune responses.

Question 48

What was demonstrated in a case study using hypoimmunogenic iPSC-derived cells?

Answer 48

Hypoimmunogenic iPSC-derived oligodendrocyte progenitor cells (OPCs) were developed as an “off-the-shelf” therapy for Canavan disease. Feng et al. 2023, transplanted these into CD mouse brains, the cells distributed widely, matured into oligodendrocytes expressing functional aspartoacylase, reduced toxic N-acetyl-l-aspartase buildup, restored myelination, improved motor function, and showed low immunogenicity.