By Cameron Chai
A research team at the Sandia National Laboratories in Albuquerque has revealed the power of a high-resolution microscopy technique named Stochastic Optical Reconstruction Microscopy (STORM) that can capture multiple molecules in living immune cells at the same time.
The team presented a paper recently at the 55th Annual Biophysical Society
Annual Meeting held in Baltimore. Jesse Aaron and JerilynTimlin deployed this
methodology to show the changes in certain protein concentration present in the
membranes of the human immune cells that come in contact with toxins from
E.coli. The team revealed that the same changes did not take place in the immune
cells coming into contact with toxins from Y.pestis, which are the bacteria
This research reveals how our immune system can withstand some bacteria, such
as E.coli, but not the plague causing bacteria. The team captured the buildup of
TLR4, a human receptor protein, which is present on the outside of immune cells
as they hunt for foreign bacteria. These receptors identify lipopolysaccharide
(LPS), a toxic chemical signifying the presence of some bacteria, and the TLR4
proteins act as mediators of our innate immunity to these infections.
According to Jerilyn Timlin, principal scientist at Sandia National
Laboratories, a cell membrane is a complicated, heterogeneous system that
consists of proteins that interact with each other simultaneously on a scale
much below the diffraction limit. The simultaneous STORM –based dual-color
imaging system and an objective-based TIRF microscope and filter-based image
splitter, has revealed how the TLR4 receptor is formed after it comes in contact
with toxic bacterial LPS.
Resolving these interactions at or below 40nm showed that TLR4 receptors club
together when they encounter the toxin. When TLR4 receptors detect toxins
emitted by E.coli, they multiply in number and form clusters on the cell