Researchers from the University of Pennsylvania have discovered that red blood cells (RBCs) can act as immune sensors. RBCs expressing Toll-like receptor 9 (TLR9) bind to the cytosine-phosphate-guanine (CpG) motif-containing DNA from mitochondria, bacteria, and plasmodia and stimulate erythrophagocytosis and innate immune response through interferon signalling. RBCs and TLR9 Besides delivering oxygen to tissues, RBCs are known to involve in pathogen immobilization and chemokine regulation. TLRs identify microbial membrane lipids and nucleic acids.
TLR9 specifically recognizes unmethylated CpG motifs in microbial DNAs. RBCs expressing TLR9 are shown to remove cell-free CpG-containing mitochondrial DNA from the lungs. In the current study, TLR9 was found on the surface of murine, chimpanzee, and human RBCs using antibodies and confocal microscopy. TLR9 binds to microbial DNA Human RBCs…
