Technological leap makes it possible
Intravital microscopy, invented in the early 19th century, allows scientists to look at the tissues and cells of live animals. The technology has been in use for generations. But particularly advanced and powerful multi-photon microscopes using infrared beams to image fluorescent cells in living tissues became commercially available in the late 1990s.
That prompted von Andrian to embark on a project to use the technology to study the immune system. He set up his lab at the CBR Institute and developed a strain of mouse that has fluorescent T-cells.
"We are among a handful of labs which started to do this at the same time," von Andrian said of using the technology to study the immune system. The microscopes produce optical sections through solid organs, similar to a CT-scan. Hundreds, even thousands of these sections are assembled into digital time-lapse videos to generate a 3-dimensional look at an immune response in real time.
The organism remains intact, providing a live look at what is happening in the immune system. The challenge in adapting the technology was that it takes 15-30 seconds to generate the necessary series of photographs to create the 3-dimensional footage and the animal must remain perfectly still for it to work.
It took a year to figure out how to keep the anesthetized animal from moving, he said. Others have also worked to develop and advance the technology, von Andrian said. His lab's distinction was in adapting the technology for use in lymphoid organs in live animals.