Effective NY-ESO-1–specific MHC II–restricted T cell receptors from antigen-negative hosts enhance tumor regression

Abstract

Adoptive transfer of T cell receptor-engineered (TCR-engineered) T cells is a promising approach in cancer therapy but needs improvement for more effective treatment of solid tumors. While most clinical approaches have focused on CD8 + T cells, the importance of CD4 + T cells in mediating tumor regression has become apparent. Regarding shared (self) tumor antigens, it is unclear whether the human CD4 + T cell repertoire has been shaped by tolerance mechanisms and lacks highly functional TCRs suitable for therapy. Here, TCRs against the tumor-associated antigen NY-ESO-1 were isolated either from human CD4 + T cells or from mice that express a diverse human TCR repertoire with HLA-DRA/DRB1*0401 restriction and are NY-ESO-1 negative. NY-ESO-1-reactive TCRs from the mice showed superior recognition of tumor cells and higher functional activity compared with TCRs from humans. We identified a candidate TCR, TCR-3598_2, which was expressed in CD4 + T cells and caused tumor regression in combination with NY-ESO-1-redirected CD8 + T cells in a mouse model of adoptive T cell therapy. These data suggest that MHC II-restricted TCRs against NY-ESO-1 from a nontolerant nonhuman host are of optimal affinity and that the combined use of MHC I-and II-restricted TCRs against NY-ESO-1 can make adoptive T cell therapy more effective.

High-affinity T cell receptors for adoptive cell transfer

“…Moreover, as engineered TCRs are traditionally designed based on reactivity to a single dominant epitope of a tumor antigen, TCRs with reactivity to subdominant epitopes of tumor antigens remain conspicuously unexplored. Even in the case of Poncette et al, while they confirmed natural processing of NY-ESO-1 116-135 by immunizing mice with full-length NY-ESO-1 DNA, they required that all of their TCRs stain positive for DR4/NY-ESO-1 116-135 tetramer (9). In the process, however, they may have screened out TCRs that target different portions of the NY-ESO-1 protein but still have potent antitumor activity.…”

“…These TCRs were shown to recognize NY-ESO 116-135 -loaded, NY-ESO-1-transduced, and naturally expressing NY-ESO-1 melanoma cell lines more effectively than the ones isolated from human CD4 + T cells. Moreover, their EC 50 values in a NY-ESO-1 peptide titration assay were almost a log-fold lower than 3 of 5 human-derived TCRs (10 -10 vs. 10 -9 M), they secreted greater maximal IFN-γ concentrations, and they had higher MFIs when stained with DR4/ NY-ESO-1 116-135 tetramer (9). One TCR, TCR-3598_2, was chosen for a combined CD4 + and CD8 + ACT study, as it showed no signs of alloreactivity or crossreactivity with any other naturally processed and presented human self-peptides that contain its recognition motif (9).…”

“…In the current issue of the JCI, Poncette and colleagues use a system that has been developed over several years by the Blankenstein laboratory to generate "optimal"affinity TCRs that bind human HLA, but recognize self-antigens such as MART-1 and NY-ESO-1 as foreign (9). Initially, Li et al developed ABab-transgenic mice with human, instead of murine, TCRαβ gene loci and then crossed them with HLA-A2-transgenic mice to form ABab-DII mice, which express human TCRs and the human HLA-A2 MHC class I (MHC I) (10).…”

“…One TCR, TCR-3598_2, was chosen for a combined CD4 + and CD8 + ACT study, as it showed no signs of alloreactivity or crossreactivity with any other naturally processed and presented human self-peptides that contain its recognition motif (9). This TCR was combined with a previously isolated HLA-A2/NY-ESO-1 157-165 -reactive TCR (15) in an ACT fibrosarcoma model where CD8 + T cells could only recognize antigen on cancer cells, while the NY-ESO-1-specific CD4 + T cells could only recognize antigen cross-presented by tumor stromal cells (9). The combination of NY-ESO-1-specific CD4 + and CD8 + T cells led to tumor regression in 10 of 10 mice, although the majority of these mice did eventually develop tumors, likely due to antigen loss (9).…”

“…This TCR was combined with a previously isolated HLA-A2/NY-ESO-1 157-165 -reactive TCR (15) in an ACT fibrosarcoma model where CD8 + T cells could only recognize antigen on cancer cells, while the NY-ESO-1-specific CD4 + T cells could only recognize antigen cross-presented by tumor stromal cells (9). The combination of NY-ESO-1-specific CD4 + and CD8 + T cells led to tumor regression in 10 of 10 mice, although the majority of these mice did eventually develop tumors, likely due to antigen loss (9). Correspondingly, this group had the highest number of CD8 + T cells in their peripheral blood and both CD4 + and CD8 + T cells within their tumors.…”