CellRaft Array for Screening and Isolation of Highly Effective Cytotoxic T Cells

Project SummaryAdoptive cell therapyACTis an emerging immunotherapy which shows significant promise in treating
both leukemia and solid tumorsas well as certain infectious diseasesACT comprises the isolation and ex vivo
expansion of cytotoxic T lymphocytesCTLsrecognizing epitopes of a mutated or aberrantly expressed protein
present almost exclusively on the surface of a patient s tumor cellsTo meet the need for personalized enrichment
of the most effective CTLsthis Phase II STTR will employ Cell Microsystemsproprietary CellRaft technology
to develop a high throughputautomated platformthe CLEAR AIRSystemto efficiently screen for and
isolate highly activetumor directed CTLs on a single cell basisThe CellRafttechnology is based on a unique
microwell array recently developed by the Allbritton Lab at the University of North Carolina at Chapel HillCell
Microsystems has an exclusive license to the CellRafttechnologycurrently marketing both the consumable
CellRaft Arrays as well as microscope accessories enabling imagingisolation and retrieval of single cells from
the arrayIn Phase I we used the CellRaft technology to assay the cytotoxic activity and kinetics of CTLsT cells
were pre treated with peptide epitopes known to be expressed on influenza infected cellsEpitope treated and
untreated CTL populations were then co incubated with cells expressing the influenza epitopes and monitored
for cytotoxic activityBy performing these assays at the single cell levela unique population ofsuper killerswere identified as those exhibiting cytotoxicity at leaststandard deviations above mean cytotoxicity levelsThese super killers were enriched by approximatelyfold in epitope treated CTLs compared to untreated CTLsThese data indicate that the CellRaft technology is amenable to performing CTL cytotoxicity assays and retrieval
of CTLs for downstream propagation and analysisIn Phase II we will build on these data bydesigning and
testing awell CellRaft Array containingsmall arrays within a single consumable to test multiple conditions
and immunoreactive epitopes in the cytotoxicity assayusing this newwell CellRaft array to assay
sequence dependent cytotoxicity of tumor cell expressed epitopesenabling rapid imaging and long term
culture on the automated CLEAR AIRSystem for longitudinal studies such as these andperforming external
validation studies at both UNC Chapel Hill and MD Anderson Cancer Center for novel CTL recognition
proteinsThis workflow will allow analysis of the T cell receptor without requiring the best killing cells to be
propagation capablean issue observed in Phase I with the best killing cellsCommerciallywe view the CellRaft
Systemas both a research tool enabling correlation of killing efficiency with the molecular characteristics of the
T cell receptorTCRand eventually as a clinical tool for identifying efficacious TCR sequences as well as other
time course based phenotypic screens