Enhanced Killing of Primary Ovarian Cancer by Retargeting Autologous Cytokine-Induced Killer Cells with Bispecific Antibodies: A Preclinical Study

Abstract

Cr release assay of fresh ovarian cancer cells exposed to autologous CIK cells increased from 21.7 F 0.3% to 89.4 F 2.1% at an E:Tratio of100:1 (P < 0.001). Anti-NKG2D antibodies attenuated the CIK activity by 56.8% on primary cells (P < 0.001). In a xenograft severe combined immunodeficient mouse model, real-time tumor regression and progression was visualized using a noninvasive in vivo bioluminescence imaging system. Four hours after CIK cell injection, we were able to visualize CD8 + NKG2D + CIK cells infiltrating Her2-expressing cancer cells on fluorescence microscopy. Mice that underwent adoptive transfer of CIK cells redirected with BSAbxCA125 and BSAbxHer2 had significant reduction in tumor burden (P < 0.001and P < 0.001) and improvement in survival (P = 0.05 and P = 0.006) versus those treated with CIK cells alone. Bispecific antibodies significantly enhanced the cytotoxicity of CIK cells in primary ovarian cancer cells and in our in vivo mouse model. The mechanism of cytolysis seems to be mediated in part by the NKG2D receptor.

The anti-tumour activity of allogeneic cytokine-induced killer cells in patients who relapse after allogeneic transplant for haematological malignancies

“…The abundant pre-clinical work on CIK cells may provide strategies for improving the efficacy and specificity of the treatment. This includes co-culture of CIK cells with tumour-Ag pulsed DCs, 31,32 bispecific antibodies to redirect CIK cells to tumour target, 33,34 or engineering CIK cells to express anti-CD19 receptor. 35 Exploiting the heterogeneous subsets within the bulk CIK cell culture is another avenue for enhancing its potency.…”

Cell vehicle targeting strategies

“…Only a few studies have described the use of an adapter-based approach to coat cell vehicles ex vivo for targeting in vivo. [144][145][146] In one of these studies, Blanco et al 144 utilized irradiated 293T cells as producers of two separate bispecific adapters: one adapter recognized the human carcinoembryonic antigen (CEA) and the CD3-n chain of the TCR, and the other adapter was comprised of a bivalent anti-CEA diabody fused to the extracellular domain of the B7.1 costimulator molecule. The combined use of both adapters served to conjugate and activate human T-cell proliferation and cytotoxicity toward CEA-expressing tumor cells.…”

“…145 These studies involved bispecific antibodies that conjugated CD3 expression on T cells to Her2 or CA125 ovarian cancer antigens. 146 Activated CIK cells coated with these adapters were able to mediate cytotoxicity toward primary ovarian cancer cells in vitro and in murine xenograft models. 146 Cell vehicle targeting strategies JC Roth et al Our group has been evaluating the use of adapters and artificial receptors (ARs) to superimpose affinity-based cell targeting activity in cells that lack adaptive immune recognition mechanisms, such as MSCs, mast cells and neutrophils.…”

Trifunctional antibodies induce efficient antitumour activity with immune cells from head and neck squamous cell carcinoma patients after radio-chemotherapy treatment

“…Bispecifi c antibodies, which are able to bind two different antigens, were developed to further enhance effi cacy. Suitable target antigens for bispecifi c antibodies include tumourassociated antigens and an antigen expressed on immune effector cells such as T cells or natural killer (NK) cells [3][4][5][6][7], to enable a transient linkage between immune effector cells and tumour cells leading to immune cell activation and lysis of tumour cells. Trifunctional antibodies combine the characteristics of classical monospecifi c antibodies and bispecifi c molecules: In addition to the two specifi c antigen binding sites, trifunctional antibodies retain their intact Fc region, which mediates recruitment and activation of accessory cells (macrophages, dendritic cells, NK cells) [11].…”