Ragon Institute of MGH, MIT, and Harvard View Institution's Website 3 articles published in JoVE Biology Visualizing the Early Stages of Phagocytosis Ali Rashidfarrokhi*2, Veronica Richina*2, Fikadu G. Tafesse1,2 1Department of Molecular Microbiology & Immunology, Oregon Health & Science University, 2Ragon Institute of MGH, MIT and Harvard Here we describe a microscope-based technique to visualize and quantify the early cascades of events during phagocytosis of pathogens such as the fungi Candida albicans and particulates that are larger than 0.5 µm including zymosan and IgG-coated beads. Immunology and Infection New Tools to Expand Regulatory T Cells from HIV-1-infected Individuals Mathieu Angin1, Melanie King1, Marylyn Martina Addo1,2 1Ragon Institute of MGH, MIT, and Harvard, 2Division of Infectious Diseases, Massachusetts General Hospital CD4+ Regulatory T cells are potent immune-modulators and serve important functions in immune homeostasis. The paucity of these cells in peripheral blood makes functional studies challenging, specifically in the context of HIV-1-infection. We here describe a method to isolate and expand functional CD4+ Tregs from peripheral blood from HIV-1-infected individuals. Immunology and Infection Determining the Phagocytic Activity of Clinical Antibody Samples Elizabeth G. McAndrew1, Anne-Sophie Dugast1, Anna F. Licht1, Justin R. Eusebio1, Galit Alter1, Margaret E. Ackerman2 1Massachusetts General Hospital, Ragon Institute of MGH, MIT, and Harvard, 2Thayer School of Engineering, Dartmouth College We present a high-throughput flow cytometric assay to determine the phagocytic activity of antigen-specific antibodies from clinical samples, utilizing fluorescent antigen-coated beads and a monocytic cell line expressing multiple Fc receptors—providing receptor usage and phagocytic activity determinations in a standardized and reproducible fashion for any antigen of interest.