CAR- T Cell

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
AchyutBora School of Biotechnology, BHU
Presented By

2. INTRODUCTION
Chimericantigenreceptors(CAR)aregeneticallyencodedartificialfusionmoleculesthatcan
reprogramthespecificityofperipheralbloodpolyclonalT-cellsagainstaselectedcellsurfacetarget.
CARsaregeneticallyengineeredreceptorsthatcombinethespecificbindingdomainsfromatumor
targetingantibodywithTcellsignalingdomainstoallowspecificallytargetedantibodyredirectedT
cellactivation.

3. HISTORY
In1987,anIsraeliimmunologist,ZeligEshhar,PhD,fromTheWeizmann
InstituteofScience,createdthefirst“chimericantigenreceptor,”an
engineeredreceptorthatdoesnotexistinnature.TheDNAencodingthe
receptorwasimplantedintheTcellssotheycouldfightandkillcancer.
Intheyear2010thefirstsuccessfulcancertreatmentwithCAR-Twasforan
advancedfollicularlymphomapatientandwasreportedbythelabofSteven
Rosenberg,M.D.,Ph.D.,chiefoftheSurgeryBranchinNCI’sCenterfor,
CancerResearch.
OnAugust30,2017,tisagenlecleucel(Kymriah)wasthefirstCART-cell
immunotherapyapprovedbytheFDA.Itwasapprovedforchildrenand
youngadultsaged25andunderwhorelapsedorwerenotrespondingto
therapyforacutelymphoblasticleukemia(ALL).

4. Chimeric antigen receptor design
Theoverallstructureofa
CAR consistsoffour
domainsjoinedinseries,
namely:
(i)anantigenrecognition
domain(targetingmoiety),
(ii)ahinge/spacer
(iii)atransmembraneelement
(iv)asignallingendodomain
Whildingand Maher ScienceDirect, 2015

5. 1) THE TARGETING MOIETY
The CAR ectodomaindetermines 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
PlayapredominantlystructuralroleintheCAR.
Somereportshavesuggestedthatdifferenthingeregionsmight
criticallycontrolsurfaceexpressionlevels,constructstabilityand
antigenbindingaffinity,whichdirectlyinfluencetheefficiencyofCAR-
redirectedeffectorfunctions.

6. 3)THECARSIGNALLINGDOMAIN
FirstgenerationCART-cellscontainasingleT-cellactivating
domain,mostcommonlyderivedfromthezetachainofthe
TCR/CD3complex.AndCD3zaloneprovidesasufficientlypotent
“signal1”fromitsthreeimmunoreceptortyrosine-basedactivation
motifs(ITAMs)tosubstitutefortheglobalsignalprovidedbythe
entireCD3complex.
SecondandthirdgenerationCARshavebeendevelopedinwhich
oneortwoco-stimulatorydomains,respectively,areplacedin
serieswithCD3z.Typically,CD28isincludedasaco-stimulatory
domainasthisprovidesanearlysecondsignalandpromoteshigh-
levelIL-2secretion.Resistancetoapoptosis.

7. BASIC CELLULAR AND HUMORAL IMMUNITY

8. PURPOSE FOR CAR-T CELL DEVELOPMENT
EscapeTumorSurveillancesMechanisms
Lowimmunogenicity
Antigenmodulation
ImmunesuppressionbytumorcellsT
regulatorycells
Inductionoflymphocyteapoptosis
DefectsinmechanismsofMHC-I
productioncanrendercancercells
“invisible”toCD8cells

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: SadelainM, et al. Nat Rev Cancer. 2003;3:35-45.

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

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

13. GENERALPROCESSESFORTCR/CAR-TCELLTHERAPY
Jonshonand June Cell Resarch2017

14. BENEFITS OF CAR-T CELL THERAPY
HLA-independentantigenrecognition
ActiveinbothCD4+andCD8+T-cells
Targetantigensincludeproteins,
carbohydrates,andglycolipids
RapidgenerationoftumorspecificT-cells
Minimalriskofautoimmunityor
GVHD(Graft-versus-hostdisease)
Alivingdrug,singleinfusion

15. DISADVANTAGES OF CAR -T CELL THERAPY
1)CytokineReleasesyndromeCRS(symptomslike
highfever,nausea,capillaryleakysyndrome)
AntiIL-6overcometheCRStoxicity
1)Neurotoxicity(i.e.confusion,seizures,orsevere
headaches.)
2)CostUSD$475,000byNovartis’swhichisequalto
Rs30,400,000

16. CONCLUSION
20 Different CAR-T
targets in clinical trials
Jonshonand June Cell Resarch2017