Immune cell-mediated tumor killing assays for cancer immunotherapy assessment
02 / 02 / 2022
We set up and designed specialized in vitro immune cell killing assays - either T cell- or NK-mediated - to test candidate compounds or antibodies for their immunomodulatory properties in enhancing the immune response against tumor cells.
Based on co-cultures of human primary immune cells (PBMCs, CD8+ T cells, NKs) and target tumor cells (e.g. MDA-MB-231 breast, SKOV-3 ovarian, A549 or H1299 lung cancer cells…) and combining HTRF technology and live cell imaging associated readouts, our assays allow for the parallel assessment of the immune and tumor components by capturing cytokinic immune response and specific tumor cell death, respectively.
While tumor cell exposure to activated immune cells is sufficient to induce an immune cell response against MDA-MB-231 tumor cells as illustrated by the increase of TNF⍺ levels (A) and decrease of the tumor cell number (B) , Atezolizumab is shown to further optimize the immune cell-mediated killing activity.
(A) Avelumab enhances NK response to MDA-MB-231 breast tumor cells, in a NK ratio-dependent manner.
MDA-MB-231 tumor cells – a representative model of Triple Negative Breast Cancer - were cultured under control and Atezolizumab- or Avelumab-treated conditions and, 24h later, activated primary NK cells were added at different E:T ratios. Twenty four hours later, supernatants were collected and analyzed by HTRF for IFN𝜸 release as a surrogate of NK-induced cell toxicity. While IFN𝜸 levels are increased in a NK-ratio dependent manner, only Avelumab and not Atezolizumab further promotes this increase whatever the E:T ratio.
(B) Avelumab enhances NK cytotoxicity on MDA-MB-231 breast tumor cells.
MDA-MB-231 tumor cells were cultured under control and Atezolizumab- or Avelumab-treated conditions and, 24h later, activated primary NK cells were added at an appropriate E:T ratio (2:1). Specific tumor cell apoptosis (using a caspase 3/7 probe) was kinetically monitored, normalized and analyzed by live cell imaging. Only Avelumab but not Atezolizumab induces an increase of apoptosis towards tumor cells.