About

The Ragon Institute of MGH, MIT and Harvard offers the following services to the Partners Healthcare research community.
Flow Cytometry
Fluorescence-activated cell sorting is a specialised type of flow cytometry. It provides a method for sorting a heterogeneous mixture of biological cells into two or more containers, one cell at a time, based upon the specific light scattering and fluorescent characteristics of each cell. It is a useful scientific instrument as it provides fast, objective and quantitative recording of fluorescent signals from individual cells as well as physical separation of cells of particular interest. The Ragon Institute contains 3 analysis instruments capable of measuring between 4 and 16 colors, as well as a 12 color cell sorter.
Imaging Core
	Confocal microscopy is a technique that utilizes a pinhole in plane confocal to the sample which when properly adjusted can exclude scattered light from above and below the focal plane of the specimen. In this way, one is able to obtain very thin optical sections using the confocal microscope. This is also accomplished through the use of multiple wavelengths of laser light. The Ragon Institute Imaging Core utilizes a Zeiss LSM 510 confocal microscope that can image four different fluorescent signals simultaneously, and up to eight discrete signals sequentially,
thereby taking full advantage of multichannel imaging. Images from multiple channels can thereby be combined to reveal precise localization of specific molecules or structures within tissues or cells. An additional benefit of confocal microscopy is that serial optical sections can be obtained in the vertical axis of the sample so that one can effectively “slice through” the sample or cell and obtain a three-dimensional reconstruction of that sample or cell based solely on the fluorescent signals. Since the confocal microscope uses photomultiplier tubes to record fluorescence intensity from each part of the sample imaged, intensity of multiple channels (fluorophores) can be quantified both in space and time. Since the confocal microscope uses lasers to scan the sample, obtaining high resolution images takes some time (on the order of one or several minutes). Therefore, the Imaging Core also is equipped with a Zeiss AxioObserver fluorescence microscope configured with high-speed filter wheels and shutters for rapid, live-cell multichannel time-lapse fluorescence imaging.
Humanized Mouse Model of HIV Infection
	Despite great effort, an ideal animal model in which to study HIV pathogenesis and test vaccine efficacy remains elusive. Recently, we and others have developed a markedly improved humanized mouse model of HIV by transplanting human CD34+ stem cells and autologous human thymic grafts into immunodeficient mice (see Brainard DM et al. Induction of robust cellular and humoral virus-specific adaptive immune responses in human immunodeficiency virus-infected humanized BLT mice. J Virol 2009; 83:7305-21).
In this model, we have achieved robust repopulation of mouse lymphoid tissues with human immune cells, and have generated robust anti-HIV cellular and humoral immune responses in these humanized mice. We believe this improved humanized mouse model will allow us to study questions regarding the biology of HIV-1 not readily approachable through human studies. The Ragon Institute Humanized Mouse Program was established in order to further develop this model, and to make it available to the wider Ragon research community. Highly experienced personnel produce these animals and perform experiments in collaboration with Ragon investigators at very reasonable cost.