The objective of this project is to set up, on the proteomic platform of Toulouse, instruments of the latest generation, both extremely sensitive and fast, in order to characterize at high throughput large series of isolated cells, with a depth of analysis of up to 5000 proteins. These state-of-the-art instruments will address the characterization of complex biological systems in all areas of life studies, such as cancer, immune response or viral infections. Living organisms are inherently complex and heterogeneous, and individual analysis of each cell is necessary to detect molecular mechanisms and markers specific to each cell. Single cell proteomics is an emerging approach that is a particularly interesting tool for exploring the complexity of biological systems, through the analysis of proteins, the molecules that directly underlie the biological functions of the cell. Single cell proteomic analysis requires ultra-sensitive mass spectrometers. Very recently, a series of innovations has made it possible to significantly lower the detection threshold of these techniques. Using miniaturized methods of cell preparation, it is already possible to analyze and quantify several thousand proteins in each of them.