CIBSS – of Infections, Symbioses, and Tumour Cells
Freiburg, 02/03/2026
The Cluster of Excellence CIBSS – Centre for Integrative Biological Signalling Studies is studying biological signals and developing solutions in the areas of health and food security.
The cells of complex organisms communicate via biological signals to coordinate tasks, form tissues, and adapt to environmental conditions. The Cluster of Excellence Centre for Integrative Biological Signalling Studies (CIBSS) at the University of Freiburg has been studying since 2019 how to understand and communicate in this ‘language of life’. Researchers from the life, natural, and engineering sciences, as well as ethics and law, are studying how living systems integrate signals to make decisions that regulate development, function, and health – from cells to organs and even entire organisms. The Cluster of Excellence is developing solutions to current global challenges in the areas of health and food security. CIBSS is part of the interdisciplinary focus area ‘Signals of Life’ in the University of Freiburg’s research profile. In May 2025, the German Research Foundation announced that CIBSS will continue to receive funding for another seven years.
More sustainable plant symbioses and new approaches against infections and cancer
Research on lectins illustrates how interdisciplinary collaboration works at CIBSS. These proteins are involved in signalling processes that are crucial for cell communication and interaction. Signalling processes often proceed according to similar principles, even in cell types that are widely dissimilar, such as pathogens, plant roots, and immune cells. The understanding of common principles opens up new research approaches and innovative applications – from improved strategies against infectious diseases to more sustainable plant symbioses and new approaches to the treatment of cancer.
“This has opened up entirely new possibilities for combating tumours that were previously considered untreatable by existing immunotherapy strategies.”
Prof. Dr Susana Minguet
Professor of Synthetic Immunology
Proteins with diverse functions: Lectins in bacterial infections
The cell biologist Prof. Dr. Winfried Römer and his team are working on understanding how pathogens manipulate the cell membranes of their host cells to cause infections. ‘One thing we’re concentrating on is the question of how lectins influence cellular processes in bacterial infections’, says Römer. Römer’s team demonstrated that bacterial lectins like LecA do not only serve as a kind of glue bacteria use to attach themselves to host cells; in addition, LecA activates cellular signalling paths that make it easier for the bacterium to get into the host cell.
The glycolipid Gb3 plays an integral role in this process. ‘Gb3 is not just a binding point for bacterial lectins but has already long been known to be a tumour marker found in excessively high concentrations on the surface of many cancer cells’, says Römer. The researchers observed that two of the lectins under study bind specifically to Gb3, which demonstrates their potential for applications even beyond infection research. For one thing, these binding perspectives open up the possibility of preventing bacterial infections in a targeted manner by blocking the lectin–Gb3 interaction. For another, Gb3 can also be used in cancer research as a target for identifying tumour cells specifically.
Lectins as tools for optimizing symbiotic partnerships in plants
The plant researcher Prof. Dr. Thomas Ott has been conducting research on lectins for a long time. One of Römer’s findings motivated him and his team to investigate whether it is possible to observe similar changes caused by lectins in the membrane in root nodule symbiosis. ‘The structural similarity of the invaginations was fascinating, even though the lectins and the mechanisms involved are ultimately different’, says Ott. In root nodule symbiosis, soil bacteria, so-called rhizobia, enter into a close partnership with plants by colonizing roots, causing the plants to form tiny nodules. There they convert nitrogen gas from the air into a form the plant can use – a process that would not be possible for the plants themselves and that provides them with an individual supply of nitrogen. The result is a natural ‘fertilizer factory’. One of Ott’s goals is to develop strategies for optimizing this valuable process and transferring it to other crop plants. That could reduce the use of synthetic fertilizers in agriculture.
Ott’s team is working with the natural lectin LDP1. The researchers succeeded in demonstrating that LDP1 accumulates in the so-called infection chamber, the region of the root in which the symbiosis between plant and rhizobia originates. In collaboration with Winfried Römer, the team investigated how LDP1 acts outside of its natural plant context. ‘We were able to use Winfried Römer’s system without having to spend months or years to develop our own’, says Ott. ‘That was a great advantage.’ The researchers found indications that the lectin under study promotes membrane invaginations under certain conditions. Unlike in the case of pathogens, where this effect is undesirable, it could be promoted in a targeted manner in plants to support symbiotic interactions.
“The close link between Susana’s experience in immune therapy and our expertise in lectin and membrane research is crucial to making such innovative approaches a reality.”
Prof. Dr Winfried Römer
Professor of Synthetic Biology of Signalling Processes
Innovative immune therapy via lectin CAR T cells
One of immunologist Prof. Dr. Susana Minguet’s areas of expertise is so-called CAR T cell therapy. This method of immune therapy involves modifying the patient’s own T cells to identify cancer cells with the help of so-called chimeric antigen receptors (CAR) and attack them. Up to now, this technology has usually been based on the CAR T cells recognizing particular proteins on tumours. In the collaboration between Minguet and Winfried Römer, the researchers hit on the idea of extending this strategy and integrating lectins into CARs, enabling T cells to identify tumour cells on the basis of altered sugar structures.
‘This opens up completely new possibilities for fighting tumours that have been regarded up to now as invulnerable to existing immune therapy strategies’, says Minguet. ‘The interdisciplinary exchange played a key role in this breakthrough.’ Now the team is focusing on optimizing how the CAR T cells react after identifying their target. ‘Identification alone is not enough to eliminate tumour cells effectively: CAR T cells must be properly activated.’
The key here is to carefully balance the signalling pathways created by CAR in the T cells: On the one hand, they must be strong enough to ensure an effective activation and the killing of the tumour cell, but on the other hand, they should not be so strong that they cause so-called T cell exhaustion. This weakens the immune response to cancer and reduces the long-term effectiveness of a therapy.
The teams of Minguet and Römer aim to continue researching the possibilities of lectins in the future. This includes further optimizing lectins via protein engineering or additionally using lectin NK cells (natural killer cells) to broaden the spectrum of immune cells equipped with lectins. Römer: ‘The close link between Susana’s experience in immune therapy and our expertise in lectin and membrane research is crucial to making such innovative approaches a reality.’