https://phys.org/news/2019-01-immune-safer-nanomedicines.html

Previously, the lab of CU Cancer Center investigator Dmitri Simberg, Ph.D., has shown that blood proteins (collectively called protein corona) coat nanoparticles, marking them for immune system attack. In particular, the Simberg lab showed that one of the most important components of the immune system, namely the complement system, cannot attack nanoparticles unless they are coated with protein corona. Now the Simberg lab shows another step in this process: Natural antibodies within the protein corona are responsible for the ability of the complement system to recognize and attack nanoparticles.

"Basically, we found that C3 deposition on nanoparticles (and thus immune system activation against nanoparticles) really depends on natural antibodies in each person's blood," says Simberg, who is also an associate professor in the Skaggs School of Pharmacy and Pharmaceutical Sciences. "We can remove these antibodies and there is very little complement system activation. Then we can add these antibodies back and there is activation.