Name: Carlota López Sánchez
Function: PhD candidate at Amsterdam UMC
Visited Institution: The Kennedy Institute of Rheumatology, University of Oxford
Period: 1st September 2025 – 31st October 2025

Background
Chronic lymphocytic leukemia (CLL) is a disease characterized the accumulation of malignant B cells in the blood, lymph nodes, and bone marrow. CLL is accompanied by profound T cell dysfunction, including impaired formation of the immunological synapse (IS) between the CLL and T cell. Current treatment options, such as chemoimmunotherapy and targeted therapies can effectively treat the disease, but are not curative. T cell-based therapies are known to be effective against aggressive B cell malignancies however, in CLL, the associated T cell dysfunction restricts their effectivity. Multispecific antibodies create synthetic IS, therefore, evaluation of the IS is necessary to assess the efficacy of these therapies. As the current mechanism for this limited response is still unknown, during this internship I aimed to investigate how different antibodies can restore IS formation using the supported lipid bilayer (SLB) system.

The main goal of my visit was to learn how to generate SLBs with the purpose of investigating the therapeutic potential of certain antibodies to target CLL cells. For this reason, I joined the Immunological Synapse group in Oxford, led by Prof. Michael Dustin. Prof. Dustin is a pioneer in the development of SLBs and its use for the investigation of the immunological synapse.

Methods
In short, the SLB consists of a phospholipid bilayer, similar to a cell membrane, to which any protein of interest can be fluorescently labeled and incorporated to mimic the membrane of a specific cell of choice (e.g. CLL cells). Moreover, T cells can be added together with our antibodies of interest, and signaling molecules can be stained to detect early signs of T cell activation. The lipid layer rests on a glass slide which makes it perfect for imaging using a special microscope.

For my research, I used this method to determine if our in house designed antibodies could be used to target CLL cells and effectively trigger T cell signaling.

Preliminary results
After being trained to generate the SLBs, I had the opportunity to test the antibodies against CLL that we designed in Amsterdam. Using Total Internal Reflection Fluorescence (TIRF) microscopy to detect only the molecules present in the surface of the cells interacting with the SLB, I was able to determine how the addition of our antibody clustered with the CLL target antigen immobilized in the SLB. A representative image is shown below (Fig. 1), where it is clear that our antibody induced the co-localization of the adhesion molecule (blue), target antigen (pink), and the T cell signaling molecule (green) between the SLB and the T cells; indicating that our antibody can be used to target CLL cells and start a response on the T cell side to eliminate the cancerous cells.

Figure 1. Representative TIRF images of immunological synapses formed by healthy donor T cells containing fluorescently labeled adhesion molecules (blue) and CLL target antigens (pink); and fluorescently labeled antibodies (red) and signaling molecules (green). IRM: Interference Reflection Microscopy.

Personal impression
The Kennedy Institute of Rheumatology is affiliated with the University of Oxford, one of the most prestigious universities in the world. My stay there not only allowed me to learn new techniques to apply to my research projects, but also gave me the opportunity to participate in interesting work discussions and strengthen our collaboration with Prof. Dustin’s group.
Over the those two months, I have formed great friendships with both people from the group and students living in the city. Being part of this university has the big advantage of free admission to museums, libraries, and colleges, so I have been able to explore Oxford’s culture in depth during this time (Fig. 2).

Figure 2. The city of Oxford and surroundings. A. Bodleian Library. B. Trinity College. C. River Thames.