Bispecific antibodies and CAR T cells targeting a TP53 mutation–associated neoantigen show discordant affinity requirements
Sarah R. DiNapoli, Katharine M. Wright, Brian J. Mog, Alexander H. Pearlman, Tushar D. Nichakawade, Nikita Marcou, Emily Han-Chung Hsiue, Michael S. Hwang, Jacqueline Douglass, Qiang Liu, Evangeline Watson, Marco Dal Molin, Joshua D. Cohen, Maria Popoli, Suman Paul, Maximilian F. Konig, Nicolas Wyhs, P. Aitana Azurmendi, Stephanie Glavaris, Jiaxin Ge, Tolulope O. Awosika, Jin Liu, Kathleen L. Gabrielson, Sandra B. Gabelli, Drew M. Pardoll, Chetan Bettegowda, Nickolas Papadopoulos, Kenneth W. Kinzler, Shibin Zhou, Bert Vogelstein
Sarah R. DiNapoli, Katharine M. Wright, Brian J. Mog, Alexander H. Pearlman, Tushar D. Nichakawade, Nikita Marcou, Emily Han-Chung Hsiue, Michael S. Hwang, Jacqueline Douglass, Qiang Liu, Evangeline Watson, Marco Dal Molin, Joshua D. Cohen, Maria Popoli, Suman Paul, Maximilian F. Konig, Nicolas Wyhs, P. Aitana Azurmendi, Stephanie Glavaris, Jiaxin Ge, Tolulope O. Awosika, Jin Liu, Kathleen L. Gabrielson, Sandra B. Gabelli, Drew M. Pardoll, Chetan Bettegowda, Nickolas Papadopoulos, Kenneth W. Kinzler, Shibin Zhou, Bert Vogelstein
View: Text | PDF
Research Article Immunology Oncology

Bispecific antibodies and CAR T cells targeting a TP53 mutation–associated neoantigen show discordant affinity requirements

Abstract

Mutation-associated neoantigens (MANAs) are highly cancer-specific targets for immunotherapy where peptides derived from intracellular mutant proteins are presented on the cell surface via HLA molecules. T cell–engaging bispecific antibodies and CAR T cells can target MANAs to eliminate cancer cells via T cell activation. However, the low antigen density of MANAs on the cell surface can limit therapeutic efficacy. Here, we investigated whether increasing the affinity of the H2 single-chain variable fragment (scFv) targeting the p53 R175H MANA (HMTEVVRHC presented on HLA-A*02:01) improves its therapeutic effect. We identified higher-affinity H2 variants via phage biopanning and a thiocyanate elution method. Increasing bispecific antibody affinity to the low nanomolar range increased cancer cell killing and tumor control in mouse xenograft models without sacrificing antigen specificity. We next asked how increasing scFv affinity impacts CAR T cell function — a matter of debate. We appended each variant scFv to a CD28z CAR, CD3γ, or the T cell receptor. In striking contrast to the bispecific antibody results, increasing CAR affinity decreased function in each CAR format due to lower T cell activation upon interaction with target cancer cells. These results have important implications for the design of future immunotherapeutic approaches targeting low-density antigens.

Authors

Sarah R. DiNapoli, Katharine M. Wright, Brian J. Mog, Alexander H. Pearlman, Tushar D. Nichakawade, Nikita Marcou, Emily Han-Chung Hsiue, Michael S. Hwang, Jacqueline Douglass, Qiang Liu, Evangeline Watson, Marco Dal Molin, Joshua D. Cohen, Maria Popoli, Suman Paul, Maximilian F. Konig, Nicolas Wyhs, P. Aitana Azurmendi, Stephanie Glavaris, Jiaxin Ge, Tolulope O. Awosika, Jin Liu, Kathleen L. Gabrielson, Sandra B. Gabelli, Drew M. Pardoll, Chetan Bettegowda, Nickolas Papadopoulos, Kenneth W. Kinzler, Shibin Zhou, Bert Vogelstein

×

Figure 3

Higher-affinity H26.8 has improved tumor control in vivo.

Options: View larger image (or click on image) Download as PowerPoint
Higher-affinity H26.8 has improved tumor control in vivo. (A) Delayed tr...
(A) Delayed treatment model design. NSG mice were inoculated with 3.5 × 105 KMS26 cells i.v. 7 days prior to treatment. On treatment day 0, mice received 107 human T cells i.v. and surgically implanted micro-osmotic continuous release pumps i.p. scDb was dosed at 0.075 mg/kg/d for 14 days. Tumor burden was measured by bioluminescence imaging. (B) Tumor burden and (C) bioluminescent images at days –1 and 14 (average radiance, means compared at day 14 by Mann-Whitney test, n = 5 per group; data are shown as mean ± SD). (D) Early treatment model design. NSG mice were inoculated with 5 × 105 NALM6R175H cells and 107 human T cells i.v. 2 days prior to treatment start. On treatment day 0, mice received surgically implanted continuous release pumps i.p. scDb was dosed at 0.075 mg/kg/d for 14 days. (E) Tumor burden and (F) bioluminescent images of mice at days –1 and 14 (average radiance, means compared at day 14 by Mann-Whitney test, n = 5 per group, representative of 2 experiments; data are shown as mean ± SD). Pump treatment period indicated by gray boxes.