MassGeneral Hospital for Children 2 articles published in JoVE Bioengineering Development of a Multicellular Three-dimensional Organotypic Model of the Human Intestinal Mucosa Grown Under Microgravity Rosangela Salerno-Goncalves1, Alessio Fasano2, Marcelo B. Sztein1 1Center for Vaccine Development, Department of Pediatrics, University of Maryland School of Medicine, 2Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children Cells growing in a three-dimensional (3-D) environment represent a marked improvement over cell cultivation in 2-D environments (e.g., flasks or dishes). Here we describe the development of a multicellular 3-D organotypic model of the human intestinal mucosa cultured under microgravity provided by rotating-wall-vessel (RWV) bioreactors. Immunology and Infection In vitro Coculture Assay to Assess Pathogen Induced Neutrophil Trans-epithelial Migration Mark E. Kusek1,2,3, Michael A. Pazos1,3, Waheed Pirzai3, Bryan P. Hurley1,3 1Department of Pediatrics, Harvard Medical School, 2Department of Pediatric Gastroenterology, MGH for Children, 3Mucosal Immunology and Biology Research Center, Massachusetts General Hospital Neutrophil trans-epithelial migration in response to mucosal bacterial infection contributes to epithelial injury and clinical disease. An in vitro model has been developed that combines pathogen, human neutrophils, and polarized human epithelial cell layers grown on transwell filters to facilitate investigations towards unraveling the molecular mechanisms orchestrating this phenomenon.