Immune hematology

The researches find that the Non-classical monocytes were long thought to play a purely surveillance role in the immune system. With the aid of a novel marker (PD-L1); Ludwig-Maximilians-Universitaet (LMU); but in Munich researchers have now shows that they are directly involve in the regulation of immune response. Monocytes comprise a functionally specific group of white blood cells and are know to play a role in the immune system.

The immune system

Based on the sets of proteins find on their surfaces; they can be divide into two major subtypes, know respectively as classical and non-classical monocytes; which serve different functions in the immune system. Up to now; non-classical monocytes have been view solely as surveillance cells that circulate in the bloodstream ;and serve to recruit other immune cells to sites of damage in the walls of blood vessels.

However, an international team led by Dr. Johan Duchêne, Mariaelvy Bianchini; Dr. Remco Megens and Professor Christian Weber of the Institute for Cardiovascular Prevention (IPEK) ;at the LMU Medical Center has now identified a specific marker for these cells. Using this tool; they then went on to show; in a mouse experimental model, that non-classical monocytes also play a direct regulatory role in the adaptive immune response in certain tissues. The new study appears in the journal Science Immunology.

The bloodstream and serve

Classical monocytes migrate to sites of inflammation in the body, where they differentiate further to produce a range of specialized immune cells that activate other components of the immune response. “They are interest in whether or not non-classical monocytes might also be able to regulate other types of immune cells in addition to acting as lookouts,” says Duchêne. The problem is that no specific marker, with which they  reliably identify, had been find for them.

But this obstacle has now been overcome. In the course of their studies on mice, Duchêne and his colleagues characterize a specific surface protein as a suitable marker with which to track non-classical monocytes. “The protein concern (PD-L1) is a know and well-study molecule that is find on the surface of cancer cells and serves to inactivate the immune response to malignant tumor cells.

Track non-classical monocytes

“It was a great surprise for us to discover that this protein is also strongly express on the surface of non-classical monocytes,” says Bianchini, who is first joint author on the study.The new marker make it possible for the authors of the new study to show that classical monocytes, which develop in the bone marrow, are convert into non-classical monocytes when they first come into contact with specialized blood vessels in the vicinity of the cortical bone.