Customer case study: Using cell avidity to explore the network of intercellular interactions of NK cells in the tumor microenvironment
Prof. Mark Lowdell
Professor of Cell & Tissue Therapy at University College London and Chief Scientific Officer of INmune Bio, Inc
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About Prof. Lowdell and his research focus

Prof. Mark Lowdell, Professor of Cell & Tissue Therapy at University College London, is a world leader in the development of cell and tissue medicines for immunotherapy and transplantation. He is also the Chief Scientific Officer of INmune Bio, Inc., which is a clinical-stage immune-oncology company focused on the development of novel immunotherapies that harness the power of patient’s innate immune system against cancer. While the latest discoveries in immuno-oncology research have led to clinical benefits, a large proportion of patients still relapses from residual disease – the recurrence of cancer cells that survive the initial treatments. INmune Bio aims to prolong cancer remission and patient’s life expectancy by controlling residual disease using a novel mechanism of action and a precision medicine approach based on natural killer (NK) cells.

The innate killing ability of NK cells serves as a compelling immunotherapeutic tool

NK cells serve as a potential immunotherapeutic tool due to their innate ability to kill cancer cells. They play a crucial role in cancer prevention by providing immune surveillance. NK cells facilitate cancer cell eradiation using two robust killing mechanisms that make them attractive candidates for immunotherapeutic tool.
First, by secretion of perforin and granzymes from the lytic granules to disrupt the cancer cell membrane and cause cancer cell lysis.

In the second mechanism, NK cells bind to the “death receptor” that sits on the surface of the cancer cell inducing signals that lead to cancer cell apoptosis.

NK cell failure is a major cause of cancer relapse

However, quite often NK cell can fail to recognize and eradicate residual cancer cells, resulting in cancer relapse and lower chance of survival. The cancer cells from relapsed patients evade NK-mediated lysis by making themselves invisible to the NK cells, and therefore inhibiting NK cell activation and tumor cell killing. The existing therapies have shown to reduce tumor burden, but are not completely curative, resulting in a high chance of cancer relapse. There is a need for a new approach to stimulate the immune response and effectively eradicate residual cancer cells.

Overcoming NK cell failure with INKmune™

For resting NK cells to become activated, multiple signals need to be delivered from the cancer cell to the immune synapse – the interface consisting of multiple intercellular binding events between a cancer cell and a NK cell. NK cells that make a strong bond to tumor cells form a more stable immune synapse, and allow the NK ligands to better communicate activating signals to the NK cells, which is required for initiating tumor cell killing. INKmune™ is a proprietary NK cell priming platform, developed by INmune Bio, that delivers signals intravenously to activate patient’s resting NK cells, and make them “ready to kill” upon encountering cancer cells. This unique approach enables researchers to prime patient’s autologous NK cells in vivo, and yields the same effect as priming in vitro.

Exploring the Network of Cellular Interactions of NK Cells in the Tumor Microenvironment

Watch a snippet of Mark Lowdell’s webinar on finding the synapse with microscopy. If you would like to download the complete webinar, click here.

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Cell avidity analysis directly measures and quantifies the synaptic interaction

Using microscopical techniques, the team of prof. Mark Lowdell saw that the NK cells seemed to form a more stable synapse with the tumor cell when they were activated. Prof. Mark Lowdell and his team use the z-Movi® Cell Avidity Analyzer as a solution to directly measure and quantify the synaptic interaction.

With cell avidity measurements, the team can rapidly distinguish NK sensitive- from NK-resistant tumor cells by quantifying amount of NK cells bound to cancer cells. In their research studies, the binding between resting NK cells and NK sensitive- (K562) tumor cells depicted a higher avidity score, indicating the formation of a stronger immune synapse. On the other hand, the binding between NK cells and NK-resistant (SKOV3) tumor cells showed a significantly lower avidity score, indicating a much weaker binding compared to NK sensitive- (K562) tumor cells (Figure 1).

Figure 1. Avidity curves showing the percentage of target-bound resting NK cells upon increasing acoustic forces. Cell avidity measurements of NK cells were performed on NK-resistant SKOV3 tumor cells (left), or NK sensitive K562 tumor cells (right).

Cell avidity measurements depict stronger binding of INKmune-primed NK cells that eradicate residual disease

Cell avidity measurements were implemented to measure and compare the binding strength of different NK cell populations (IL-2 primed, IL-15 primed and INKmune-primed NK cells) to NK-resistant SKOV3 cancer cells. INKmune-primed NK cells had higher avidity to SKOV cells compared to IL-2 primed, IL-15 primed and resting NK cells (Figure 2). This finding validates that INKmune-primed NK cells form much stronger immune synapses with cancer cells, which is crucial to properly activate NK cells, and deliver lytic enzymes and apoptosis signals to kill resistant cancer cells. Compared with conventional cytokine activation using  IL-2 or IL-15, which are often associated with off-target toxicities, this technology enables adequate NK cell activation required for NK-mediated, without inducing significant off-target toxicities on healthy tissues. Another advantage of INKmune-primed NK cells over cytokine-primed NK cells is that these NK cells are less prone to be exhausted, as INKmune-primed NK cells express biomarkers that help them overcome inhibition by regulatory cells and hypoxia in the tumor microenvironment.
With this experiment, the use of cell avidity technology demonstrated that INKmune increases NK cell killing of tumor cells by strengthening the binding of the NK to the tumor cell.  It has become evident that beyond conventional assays, cell avidity measurements with the z-Movi® Cell Avidity Analyzer provides key information that can accelerates immunotherapy development by accurately predicting in vivo and clinical efficacy.
Figure 2. Cell avidity between resting-, INKmune-primed-, IL-2 primed-, IL-15 primed- NK cells and NK-resistant SKOV3 tumor cells.The avidity curves show the percentage of target-bound NK cells upon increasing acoustic forces. rForce indicates relative force.

Cell avidity technology provides key information to accelerate immunotherapy development

“The success of INKmune offers substantial clinical benefits, as INKmune-primed NK cells can become a more affordable immunotherapeutic option by in vivo activation of patient’s own autologous NK cells. It has become evident that beyond conventional assays, cell avidity measurements with the z-Movi® Cell Avidity Analyzer provide key information that can accelerate immunotherapy development by accurately predicting in vivo and clinical efficacy.”

Watch the full interview here

Watch the webinar!

In this webinar, Prof. Mark Lowdell how to use the z-Movi® Cell Avidity Analyzer to dissect the temporal nature of the synaptic formation between NK cell and tumor cell.

Learn more about the z-Movi® Cell Avidity Analyzer