Janssen Pharmaceutical Companies of Johnson and Johnson 4 articles published in JoVE Immunology and Infection Studying Cryptosporidium Infection in 3D Tissue-derived Human Organoid Culture Systems by Microinjection Devanjali Dutta1, Inha Heo1,3, Roberta O'Connor2 1Hubrecht Institute, Oncode Institute, Royal Netherlands Academy of Arts and Sciences (KNAW), UMC Utrecht, 2Veterinary Microbiology and Pathology, College of Veterinary Medicine, Washington State University, 3Janssen Pharmaceutica We describe protocols to prepare oocysts and purify sporozoites for studying infection of human intestinal and airway organoids by Cryptosporidium parvum. We demonstrate the procedures for microinjection of parasites into the intestinal organoid lumen and immunostaining of organoids. Finally, we describe the isolation of generated oocysts from the organoids. Immunology and Infection Single-cell Screening Method for the Selection and Recovery of Antibodies with Desired Specificities from Enriched Human Memory B Cell Populations Stuart T. Perry1, Elissa Keogh1, Mike Morton1, Wouter Koudstaal2, Gabriel Pascual1 1World Without Disease Accelerator, Janssen Pharmaceutical Companies of Johnson and Johnson, 2Janssen Prevention Center, Janssen Pharmaceutical Companies of Johnson and Johnson The BSelex method to identify and recover individual antigen-specific antibodies from human peripheral blood mononuclear cells combines flow cytometry with single cell PCR and cloning. Neuroscience In Vitro Assay for Studying the Aggregation of Tau Protein and Drug Screening Rosa Crespo1, Wouter Koudstaal1, Adrian Apetri1 1Janssen Prevention Center, Janssen Pharmaceutical Companies of Johnson and Johnson The tau aggregation assay described in this manuscript mimics the anticipated features of in vivo tau misfolding and aggregation. Neuroscience Cell-based Assay to Study Antibody-mediated Tau Clearance by Microglia Donata De Marco1, Renske Taggenbrock2,3, Rosa Crespo3, Wouter Koudstaal3, Elizabeth Ramsburg4, Adrian Apetri3 1Neuroscience Discovery, Janssen Pharmaceutical Company of Johnson & Johnson, Belgium, 2Department of Hematopoiesis, Sanquin Research and Landsteiner Laboratory, The Netherlands, 3Janssen Prevention Center, Janssen Pharmaceutical Company of Johnson & Johnson, The Netherlands, 4Neuroscience Discovery, Janssen Pharmaceutical Company of Johnson & Johnson, Pennsylvania Here we describe a cell-based assay to quantitatively assess tau uptake by microglia with the aim of creating an investigational tool to better characterize the mechanisms of action of anti-tau antibodies.