Monocyte uptake of polymeric peptidoglycan is bimodal and governed by complement C3 and C4 opsonins.

ABSTRACT: Peptidoglycans (PGNs) are structural polymers of the bacterial cell wall and a common microbial molecular pattern encountered by the immune system daily. Low levels of PGNs are constitutively present in the systemic circulation in humans and rise during inflammatory pathologies. Since all known PGN sensors are intracellular, PGN internalization is a prerequisite for the initiation of cellular immune responses. Here, we report the mechanisms controlling the recognition and uptake of polymeric PGNs by circulating human mononuclear phagocytes. We found that complement C3 and C4 opsonins govern PGN recognition and internalization, but no single opsonin is indispensable because of multiple uptake redundancies. We observed a bimodal internalization of polymeric PGNs with distinct requirements fo

SUBMITTER: Popescu NI 

PROVIDER: S-EPMC11790019 | biostudies-literature | 2024 Dec

REPOSITORIES: biostudies-literature