Introduction to CAR(Chimeric Antigen Receptor)-T Cell and its role in Immunotherapy

1. Introduction to CAR (Chimeric Antigen Receptor )- T
Cell and its role in Immunotherapy
Achyut Bora School of Biotechnology, BHU
Presented By

2. INTRODUCTION
 Chimeric antigen receptors (CAR) are genetically encoded artificial fusion molecules that can
reprogram the specificity of peripheral blood polyclonal T-cells against a selected cell surface target.
 CARs are genetically engineered receptors that combine the specific binding domains from a tumor
targeting antibody with T cell signaling domains to allow specifically targeted antibody redirected T
cell activation.

3. HISTORY
 In 1987, an Israeli immunologist, Zelig Eshhar, PhD, from The Weizmann
Institute of Science, created the first “chimeric antigen receptor,” an
engineered receptor that does not exist in nature. The DNA encoding the
receptor was implanted in the T cells so they could fight and kill cancer.
 In the year 2010 the first successful cancer treatment with CAR-T was for an
advanced follicular lymphoma patient and was reported by the lab of Steven
Rosenberg, M.D., Ph.D., chief of the SurgeryBranch in NCI’s Center for ,
Cancer Research.
 On August 30, 2017, tisagenlecleucel (Kymriah) was the first CAR T-cell
immunotherapy approved by the FDA. It was approved for children and
young adults aged 25 and under who relapsed or were not responding to
therapy for acute lymphoblastic leukemia (ALL).

4. Chimeric antigen receptor design
The overall structure of a
CAR consists of four
domains joined in series,
namely:
(i) an antigen recognition
domain (targeting moiety),
(ii) a hinge/spacer
(iii) a transmembrane element
(iv) a signalling endodomain
Whilding and Maher ScienceDirect, 2015

5. 1) THE TARGETING MOIETY
 The CAR ectodomain determines target specificity and, most
commonly, contains elements derived from a monoclonal
antibody.
 co-express both antibody variable heavy (VH) and light chains
(VL) in two separate polypeptide chains, thereby creating a
single chain variable fragment (scFv)
2) THE HINGE/SPACER AND TRANS-MEMBRANE
DOMAIN
 Play a predominantly structural role in the CAR.
 Some reports have suggested that different hinge regions might
critically control surface expression levels, construct stability and
antigen binding affinity, which directly influence the efficiency of CAR-
redirected effector functions .

6. 3) THE CAR SIGNALLING DOMAIN
 First generation CAR T-cells contain a single T-cell activating
domain, most commonly derived from the zeta chain of the
TCR/CD3 complex. And CD3z alone provides a sufficiently potent
“signal 1” from its three immunoreceptor tyrosine-based activation
motifs (ITAMs) to substitute for the global signal provided by the
entire CD3 complex.
 Second and third generation CARs have been developed in which
one or two co-stimulatory domains, respectively, are placed in
series with CD3z. Typically, CD28 is included as a co-stimulatory
domain as this provides an early second signal and promotes high-
level IL-2 secretion. Resistance to apoptosis.

7. BASIC CELLULAR AND HUMORAL IMMUNITY

8. PURPOSE FOR CAR-T CELL DEVELOPMENT
Escape Tumor Surveillances Mechanisms
 Low immunogenicity
 Antigen modulation
 Immune suppression by tumor cells T
regulatory cells
 Induction of lymphocyte apoptosis
 Defects in mechanisms of MHC-I
production can render cancer cells
“invisible” to CD8 cells

9. VARIOUS WAYS OF DIRECTING IMMUNITY AGAINST CANCER
CELLS

10. ENGINEERING OF CAR-T CELL RECEPTOR
CAR, chimeric antigen receptor; mAb,
monoclonal antibody; TAA, tumor -associated
antibody; TCR, T -cell receptor.
Ref: Sadelain M, et al. Nat Rev Cancer. 2003;3:35-45.

11. CAR GENE TRANSDUCTION IN T-CELLS
Ref: Sadelain M, et al. Nat Rev Cancer. 2003;3:35-45. Brentjens RJ, et al. Nat Med. 2003;9:279-286

12. UPGRADED GENERATIONS OF CARS
Jessica Hartmann et al. EMBO Mol Med. 2017

13. GENERAL PROCESSES FOR TCR/CAR-T CELL THERAPY
Jonshon and June Cell Resarch 2017

14. BENEFITS OF CAR-T CELL THERAPY
 HLA-independent antigen recognition
 Active in both CD4+ and CD8+ T-cells
 Target antigens include proteins,
carbohydrates, and glycolipids
 Rapid generation of tumor specific T-cells
 Minimal risk of autoimmunity or
GVHD(Graft-versus-host disease)
 A living drug, single infusion

15. DISADVANTAGES OF CAR-T CELL THERAPY
1) Cytokine Release syndrome CRS (symptoms like
high fever, nausea, capillary leaky syndrome)
 Anti IL-6 overcome the CRS toxicity
1) Neurotoxicity( i.e. confusion, seizures, or severe
headaches.)
2) Cost USD $ 475,000 by Novartis’s which is equal to
Rs 30,400,000

16. CONCLUSION
20 Different CAR-T
targets in clinical trials
Jonshon and June Cell Resarch 2017