Phagocytic and endocytosing cells

Phagocytic and endocytosing cells, including macrophages, neutrophils, and dendritic cells, are essential components of the innate immune system that internalize and degrade pathogens, apoptotic cells, and debris (StatPearls, 2023). These cells maintain tissue homeostasis and bridge innate and adaptive immunity by processing and presenting antigens to T-cells (NIH, 2022). In drug development, these cells are not typically defined as a single molecular target but are instead targeted as a cell population to modulate immune responses or to facilitate the delivery of encapsulated therapeutics (PubMed, 2021). For example, liposomal formulations are designed to be sequestered by these cells to treat intracellular infections or to alter the tumor microenvironment (Nature Reviews Drug Discovery, 2019). However, the mononuclear phagocyte system (MPS) also acts as a major biological barrier, as it rapidly clears many nanomedicines from the bloodstream, reducing their half-life and efficacy (Journal of Controlled Release, 2020). Consequently, therapeutic strategies often focus on either evading these cells to reach other targets or specifically harnessing their endocytic capacity for localized action.

Other names

PhagocytesEndocytic cellsProfessional phagocytesMononuclear phagocyte systemReticuloendothelial system

Internalization of therapeutic agents via phagocytic or endocytic pathways to modulate immune function or achieve localized drug release.