Regeneron Pharmaceuticals, Inc 3 articles published in JoVE Chemistry Host Cell Protein Analysis using Enrichment Beads Coupled with Limited Digestion Sisi Zhang1, Hui Xiao1, Ning Li1 1Analytical Chemistry, Regeneron Pharmaceuticals Inc. A protocol is presented for enriching host cell proteins (HCPs) from drug products (DP) and detecting peptides using proteome enrichment beads. The method is demonstrated using an in-house manufactured monoclonal antibody (mAb) drug substance (DS), which is a well-characterized reference material for evaluating and comparing different methods in terms of performance. Immunology and Infection Flow Cytometric Characterization of Murine B Cell Development Faith M. Harris*1, Karoline A. Meagher*1, Maggie Zhong1, Benjamin J. Daniel2, Mark Eckersdorff1, Jesse A. Green1, Vera Voronina1, Chunguang Guo1, Andre Limnander3, Lynn E. Macdonald1 1Regeneron Tech Centers, Regeneron Pharmaceuticals, Inc., 2Regeneron Therapeutic Proteins, Regeneron Pharmaceuticals, Inc., 3Immunology and Inflammation, Regeneron Pharmaceuticals, Inc. We describe herein a simple analysis of the heterogeneity of the murine immune B cell compartment in the peritoneum, spleen, and bone marrow tissues by flow cytometry. The protocol can be adapted and extended to other mouse tissues. Genetics Single-cell RNA Sequencing and Analysis of Human Pancreatic Islets Yurong Xin1, Christina Adler1, Jinrang Kim1, Yueming Ding1, Min Ni1, Yi Wei1, Lynn Macdonald1, Haruka Okamoto1 1Regeneron Pharmaceuticals, Inc Here, we present a protocol to generate high-quality, large-scale transcriptome data of single cells from isolated human pancreatic islets using a droplet-based microfluidic single-cell RNA sequencing technology.