Trispecific killer engager 161519 enhances natural killer cell function and provides anti-tumor activity against CD19-positive cancers

Objective:Natural killer(NK)cells have gained considerable attention due to their potential in treating"cold tumors,"and are therefore considered as one of the new strategies for curing cancer,by using worldwide development of their new possibilities and interventions with NK cell-related therapeutic products.Methods:We constructed a trispecific killer engager(TriKE)consisting of anti-CD16,IL-15,and anti-CD19.This TriKE was designed to attract CD19^(+)tumor cells to CD16^(+)NK cells,whereas IL-15 sustained the proliferation,development,and survival of NK cells.Results:Treatment with 161519 TriKE in the presence of CD19^(+)targets upregulated expression of CD69,CD107 a,TRAIL,IFN-γ,and TNF-α in NK cells,and significantly improved the proliferation and cytotoxicity of NK cells.NK cells"armed"with 161519 TriKE showed stronger cytolysis against CD19+targets compared with that of"unarmed"NK cells.A preclinical model of B-cell lymphoma in human peripheral blood mononuclear cell-reconstituted xenograft mice showed significant inhibition of tumor growth and prolonged overall survival after treatment with 161519 TriKE,when compared with that in control mice or mice treated with 1619 BiKE.Combined use of IL-2 was a more effective treatment with 1619 BiKE,when compared with that using 161519 TriKE.Conclusions:The newly generated 161519 TriKE enhanced the proliferation,activation,cytokine secretion,and cytotoxicity of NK cells in the presence of CD19+tumor cells.The 161519 TriKE aided inhibition of tumor growth and prolonged the overall survival of murine xenografts,and could be used to treat CD19-positive cancers.

Preclinical characterization and comparison between CD3/CD19 bispecific and novel CD3/CD19/CD20 trispecific antibodies against B-cell acute lymphoblastic leukemia:targeted immunotherapy for acute lymphoblastic leukemia

The CD19-targeting bispecific T-cell engager blinatumomab has shown remarkable efficacy in patients with relapsed/refractory B-cell precursor acute lymphoblastic leukemia.However,several studies showed that blinatumomab has a short plasma half-life due to its low molecular weight,and thus its clinical use is limited.Furthermore,multiple trials have shown that approximately 30%of blinatumomab-relapsed cases are characterized by CD19 negative leukemic cells.Here,we design and characterize two novel antibodies,A-319 and A-2019.Blinatumomab and A-319 are CD3/CD19 bispecific antibodies with different molecular sizes and structures,and A-2019 is a novel CD3/CD19/CD20 trispecific antibody with an additional anti-CD20 function.Our in vitro,ex vivo,and in vivo experiments demonstrated that A-319 and A-2019 are potent antitumor agents and capable of recruiting CD3 positive T cells,enhancing T-cell function,mediating B-cell depletion,and eventually inhibiting tumor growth in Raji xenograft models.The two molecules are complementary in terms of efficacy and specificity profile.The activity of A-319 demonstrated superior to that of A-2019,whereas A-2019 has an additional capability to target CD20 in cells missing CD19,suggesting its potential function against CD19 weak or negative CD20 positive leukemic cells.

Antibody variable region engineering for improving cancer immunotherapy

The efficacy and specificity of conventional monoclonal antibody(mAb)drugs in the clinic require further improvement.Currently,the development and application of novel antibody formats for improving cancer immunotherapy have attracted much attention.Variable region-retaining antibody fragments,such as antigen-binding fragment(Fab),single-chain variable fragment(scFv),bispecific antibody,and bi/trispecific cell engagers,are engineered with humanization,multivalent antibody construction,affinity optimization and antibody masking for targeting tumor cells and killer cells to improve antibody-based therapy potency,efficacy and specificity.In this review,we summarize the application of antibody variable region engineering and discuss the future direction of antibody engineering for improving cancer therapies.

DNA Nanotechnology for Modulating the Growth and Development of Neurons

Late prenatal growth,early postnatal growth,and layering of the neocortical neurons(NC-Ns)play determining roles in the development of the cerebral cortex(CC).Here,we systematically explore the interactive role of neuronal surface receptors(NSRs)on cytoskeleton activation(CA)and the piconewton(pN)force generation(P-FG)and their influence on the proper development,growth,and functioning of neurons using a designed DNA nanomechanical device(DNA-NMD).