POZ Community Forums

Meds, Mind, Body & Benefits => Research News & Studies => Topic started by: Mishma on August 01, 2012, 03:38:03 pm

Title: Amazing new tool used in HIV Research
Post by: Mishma on August 01, 2012, 03:38:03 pm
This technique for real time imaging wasn't around when I was playing bench scientist. This is and will be a very important tool in biological research. I think the language used in the abstract is pretty straight forward especially for those of us that have been following HIV infection of T Cells. I don't know how they block egress of the T Cells from the infected lymphoid tissue as I only have access to the absract.



HIV-infected T cells are migratory vehicles for viral dissemination
http://www.nature.com/nature/journal/vaop/ncurrent/full/nature11398.html?WT.ec_id=NATURE-20120802


Thomas T. Murooka,    Maud Deruaz,    Francesco Marangoni,    Vladimir D. Vrbanac,    Edward Seung, Ulrich H. von Andrian,    Andrew M. Tager,    Andrew D. Luster    & Thorsten R. Mempel
AffiliationsContributionsCorresponding author
Nature (2012) doi:10.1038/nature11398
Received 24 February 2012 Accepted 16 July 2012 Published online 01 August 2012

After host entry through mucosal surfaces, human immunodeficiency virus-1 (HIV-1) disseminates to lymphoid tissues to establish a generalized infection of the immune system. The mechanisms by which this virus spreads among permissive target cells locally during the early stages of transmission and systemically during subsequent dissemination are not known1. In vitro studies suggest that the formation of virological synapses during stable contacts between infected and uninfected T cells greatly increases the efficiency of viral transfer2. It is unclear, however, whether T-cell contacts are sufficiently stable in vivo to allow for functional synapse formation under the conditions of perpetual cell motility in epithelial3 and lymphoid tissues4. Here, using multiphoton intravital microscopy, we examine the dynamic behaviour of HIV-infected T cells in the lymph nodes of humanized mice. We find that most productively infected T cells migrate robustly, resulting in their even distribution throughout the lymph node cortex. A subset of infected cells formed multinucleated syncytia through HIV envelope-dependent cell fusion. Both uncoordinated motility of syncytia and adhesion to CD4+ lymph node cells led to the formation of long membrane tethers, increasing cell lengths to up to ten times that of migrating uninfected T cells. Blocking the egress of migratory T cells from the lymph nodes into efferent lymph vessels, and thus interrupting T-cell recirculation, limited HIV dissemination and strongly reduced plasma viraemia. Thus, we have found that HIV-infected T cells are motile, form syncytia and establish tethering interactions that may facilitate cell-to-cell transmission through virological synapses. Migration of T cells in lymph nodes therefore spreads infection locally, whereas their recirculation through tissues is important for efficient systemic viral spread, suggesting new molecular targets to antagonize HIV infection.



http://www.ncbi.nlm.nih.gov/pubmed/21909917

Methods Mol Biol. 2012;757:247-57.
Multiphoton intravital microscopy to study lymphocyte motility in lymph nodes.
Murooka TT, Mempel TR.
Source
Center for Immunology and Inflammatory Diseases and Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
Abstract
Intravital microscopy (IVM) allows for the direct in vivo visualization of dynamic biological processes in their physiological context at high spatial and temporal resolution. Novel nonlinear optical imaging modalities, most prominently multiphoton microscopy, have extended the spectrum of cellular functions amenable to IVM investigation to include migration and cell-cell interactions occurring deep inside the highly light-scattering environments of solid tissues, which had so far been inaccessible to conventional microscopy techniques. This has led to important new insights into immune cell behavior at steady state, as well as their change in behavior during an immune response. Here, we describe in detail a technique that allows for the monitoring of lymphocyte motility in the lymph nodes of mice at the single cell level using multiphoton intravital microscopy (MP-IVM).