3. PCD: Immune cells

The primary goal of this project is to comprehend the role of immune cells in Paraneoplastic Cerebellar Degeneration (PCD) and the associated cancer, aiming to delineate central nervous system (CNS) protective and CNS damaging immune responses. Cytotoxic CD8 T cells have been proposed to play a crucial role in CNS damage. Additionally, autopsy studies have revealed significant microglial activation in the late stages of the disease. We are delving into a detailed investigation of these cells, focusing on microglia, infiltrated monocytes, and lymphocytes, and examining how their localization and function evolve during the progression of the disease.

Our current emphasis is on microglia, the resident immune cells in the CNS, concerning PCD. While prior studies have indicated the involvement of microglia in various neurodegenerative diseases, their specific role in PCD remains unclear. Microglia are known to be responsive to environmental changes, making them crucial indicators of pathological shifts in the brain. Our objective is to characterize immune profiles in different brain areas, with a special focus on microglial reactivity near the Purkinje neuron layer in the cerebellum.

To achieve this goal, we are utilizing Imaging Mass Cytometry (IMC) for quantifying immune infiltration in affected tissues, specifically the cerebellum and the tumor site. This technique proves instrumental in identifying and analyzing the interplay between various cell types, including infiltrating immune cells, essential for comparing diseased tissue with healthy controls. The cerebellum, with its intricate neuronal network, poses a unique challenge. Neurons in this area exhibit a wide range of phenotypes, sizes, and interconnections, making accurate segmentation and analysis challenging.

A key tool in our research is the Hyperion Imaging System which is located at the Flow Cytometry Core Facility. This advanced system allows us to analyze tissue microarrays containing sections from different brain areas (e.g., cerebellum, medulla oblongata, frontal cortex), ovarian tumor tissue and control tissues such as tonsils. The Hyperion System is particularly advantageous for its ability to simultaneously analyze approximately 40 markers with minimal background noise and autofluorescence, avoiding the signal overlap often seen with fluorophore-based techniques.