I hope you were there for this talk - 3D Microscopy

The single-most incredible presentation at the conference.  Dr Kedar Narayan presented on some amazing new technology which is allowing us to view HIV in a completely different light.  He somehow managed to explain what is clearly a very complex principle in simple terms, and with plenty of humour sprinkled in.

• traditional electron microscopy only provides a 2D image of the cell
• focuses ion beam scanning electron microscopy (FIB-SEM) allows a 3D image
• the tissue is embedded in a block, with the side face open to the EM scanning
• the FIB laser is used to slice the tissue (like a deli slicer/cutting a loaf of bread) to reveal the next layer of the tissue
• the EM can then image the 2nd layer
• this is repeated 1000s of times to obtain a stack of images (like a CT scan)
• computer software can generate a 3D image of the tissue, including all the internal structures
• FIB-SEM can be applied to HIV
• HIV virons actually use small tunnels from intracellular vesicles to the extracellular surface to escape the cell
• this explains why other studies have found that the pH of vesicles were less acidic than expected (i.e. because they were actually connected to the extracellular membrane)
• virological synapse
• the dendritic cell actually “hugs” the T cell
• rather than individual projections from the cell, the DC actually has lasagne like sheets (veils) to connect with the T cell
• this excludes all drugs since the synapse is covered by the “hug”
• often thought that the T cell is passive in receiving antigen presentation
• not so - they can reach into the DC to sample for virus

What an exciting start to the day (following on from the excellent trainee sessions this morning), and the rest of the session proved equally as informative...stay tuned