SpLICe (Spectral Library of Immune Cells).

Spectral libraries fulfill multiple functions in biological and analytical applications. For biologists, these libraries provide a valuable resource to verify the presence and abundance of specific proteins or pathways within a selected cell type, and thus determine the feasibility of further experiments. Despite advances, existing libraries are incomplete and provide researchers only a limited amount of information. To address this, we introduce the Spectral Library of Immune Cells (SpLICe), a comprehensive resource covering five main cell populations comprising nearly 9,000 protein groups, 123,554 proteotypic peptides, and 135,240 spectra. SpLICe supports the quantification of more than half of total murine proteins annotated by UniProtKB/Swiss-Prot, enabling monitoring of selected proteins or pathways from Reactome pathways, GO Biological Process, GO Molecular Function, or GO Cellular Component databases. The platform also provides insights about the relative abundance of proteins and their associated transcripts and supports the generation of targeted mass spectrometry assays by identifying available proteotypic peptides and evaluating their suitability for targeted MS analyses via an integrated scoring system.