Changes to TCR Repertoire in TILs Following GLA-SE
inflammation, tumor
INFLAMMATION, TUMOR, INFILTRATION
To delineate whether the increased T-cell infiltration was due to a generalized inflammation vs clonal expansion against putative tumor antigens, we analyzed TILs, generated from core biopsy samples and expanded ex vivo, using TCR sequencing. In total, 10 patients had evaluable TILs from both pretreatment and posttreatment samples. Although there was no discernible increase in TIL clonality after IT GLA-SE among all patients (mean [SD], 0.11 [0.09] before treatment and 0.16 [0.11] after treatment), increased clonality was observed in patients with local durable response (from 0.10 to 0.20), as opposed to those with limited response (from 0.07 to 0.06) (eFigure 8 in The greatest increase in TIL clonality was seen in a patient with durable local response) (eTable in Of the dominant TCR clonotypes, CASSDGTGFSSGYTF was present at a very low frequency IT GLA-SE in only 1 unique DNA rearrangement (14 template reads, <0.01% relative frequency); after IT GLA-SE, this TCR rearrangement expanded to become the dominant clone, contributing more than 30 000 template reads using 13 different variable gene families (To phenotype these dominant clones, we performed single-cell sorting and targeted gene reverse transcription using nested polymerase chain reaction in posttreatment PMBCs, where we found these TCRs frequently present. Multiple singlets with matching TCR β sequence were isolated from posttreatment PBMCs. By RNA sequencing, we found high levels of CD4