Activated T cells from umbilical cord blood armed with anti‐CD3 × anti‐CD20 bispecific antibody mediate specific cytotoxicity against CD20+ targets with minimal allogeneic reactivity: a strategy for providing antitumor effects after cord blood transplants

Abstract

BACKGROUND In this study, we asked whether anti-CD3-activated T cells (ATCs) from cord blood (CB) could be expanded and targeted to solid tumors or hematologic malignancies for infusions after unrelated CB stem cell transplant and whether cord blood ATCs (CBATCs) could reduce alloresponsiveness. STUDY DESIGN AND METHODS CB mononuclear cells (MNCs) were activated with anti-CD3 (20 ng/mL) and expanded for 14 days in interleukin-2 (100 IU/mL). CBATCs were armed with anti-CD3 × anti-CD20 (CD20Bi) or anti-CD3 × anti-Her2 (Her2Bi) bispecific antibodies (CBaATCs) and tested for specific cytotoxicity, cytokine secretion, and alloresponsiveness. RESULTS Our results show the mean expansion of CBATCs to be 37-fold after 14 days of culture from either frozen (n = 4) or fresh (n = 4) CB units. Cytotoxicity was optimal when CBATCs were armed with 50 ng of CD20Bi/106 cells. Cytotoxicity peaked between Day 8 and Day 10 for both bispecific antibodies. At an effector-to-target ratio of 25:1, the mean cytotoxicities of CBATCs armed with Her2Bi or CD20Bi were 40% (n = 4) and 30% (n = 4), respectively. CBaATCs exhibited peak specific interferon-γ enzyme-linked immunosorbent spots on Day 10. CBATCs and CBaATCs suppressed responsiveness to alloantigens by 20% to 50% when compared with normal allogeneic peripheral blood MNC response. CONCLUSION We showed that armed CBATCs mediate specific cytotoxicity, secrete low levels of cytokines and chemokines, and demonstrate attenuated response to alloantigens.

Bispecific T-Cell Redirection versus Chimeric Antigen Receptor (CAR)-T Cells as Approaches to Kill Cancer Cells

“…Based on pioneering efforts by Lawrence Lum and his colleagues at the Karmanos Cancer Institute (KCI), these and similar methods have been used to generate conjugated bispecific IgGs of several anti-tumor antibodies. These include clinical candidates such as anti-HER2 trastuzumab × OKT3 (Her2bi) [239] (clinical trial NCT03406858 [240]), anti-EGFR cetuximab × OKT3 (EGFR-bi) [237] (clinical trial NCT02620865 [241]), anti-GD2 3F8 × OKT3 (GD2bi) [238] (clinical trial NCT02173093 [242]) and anti-CD20 rituximab × OKT3 (called CD20bi) [243]. Note that all of these approaches utilize long-existing antibodies (e.g., trastuzumab, rituximab and cetuximab, antibody 3F8) which are chemically conjugated with the “original” anti-CD3ε antibody, OKT3 [244].…”

Natural Killer (NK)- and T-Cell Engaging Antibody-Derived Therapeutics

“…Finally, Lum and colleagues investigated the use of activated T-cells from cord blood as a cellular therapeutic, armed ex vivo with bispecific abs targeting CD20 or HER2/neu on the one side, and engaging CD3 on the other [107]. Cordblood MNCs were first incubated ex vivo with an anti-CD3 mab and IL-2, to activate and expand the T-cells.…”

Expansion of T-cells from the cord blood graft as a predictive tool for complications and outcome of cord blood transplantation

“…These bispecific antibodies likely work in similar way as the magnetic beads used for activation where interaction between the CD3-expressing cell and the CD20-expressing target cell crosslinks the TCR complexes on the T cell allowing it to perform cytotoxic action. This method has proven efficacious also for CB-derived T cells which, after 14 days of IL-2 expansion with OKT3 (anti-CD3) and armed with anti-CD3 x anti-CD20 bispecific antibodies, could mediate specific cytotoxicity versus CD20+ targets in vitro (348). It is unclear how T cells in the referred paper can perform cytolytic action without apparent costimulation.…”