Microparticles released by Listeria monocytogenes-infected macrophages are required for dendritic cell-elicited protective immunity

Cell-free Tumor Microparticle Vaccines Stimulate Dendritic Cells via cGAS/STING Signaling

“…Although apoptotic cells are enriched in eat-me signal phosphatidylserine (27), they are bigger than microparticles and likely less efficient to be taken up and processed by DCs on a particle basis. Furthermore, in addition to being internalized and processed, microparticles can directly transfer MHC class I-peptide complexes onto DC surfaces, as we reported in a Listeria infection model (14), further enhancing the efficiency and potency of antigen presentation by microparticles. An interesting and important finding of the present study is that T-MPs can activate DCs to upregulate costimulatory molecules and produce inflammatory cytokines simultaneously, suggesting that T-MPs contain endogenous activators of innate immunity.…”

“…We have recently demonstrated that microparticles can mediate antigen transfer from macrophages to DCs (14), which prompted us to examine whether T-MPs could function as a cell-free vaccine for cancer immunotherapy. In the present study, we show that T-MPs are not only capable of providing tumor antigens to DCs but also conditioning DCs toward an immunogenic phenotype via activation of type I IFN production, leading to potent antitumor immunity in both prophylactic and therapeutic settings.…”

“…Recently, we have demonstrated that tumor cell-derived microparticles (T-MP) can serve as a safe and efficient carrier to deliver chemotherapeutic drugs to tumor cells, whereas their capacity as a novel vaccine platform remains to be determined (13). In another study, we demonstrated that microparticles released by Listeria monocytogenes-infected macrophages could transfer L. monocytogenes antigens to DCs, leading to the induction of protective adaptive immune responses against the bacteria (14), implicating the potential of microparticles as a vehicle for antigen delivery and DC targeting. In the present study, we provide evidence that T-MPs may represent a novel tumor vaccine due to their possession of both tumor antigens and innate DNA signals.…”

Reversing drug resistance of soft tumor-repopulating cells by tumor cell-derived chemotherapeutic microparticles

“…These membrane vesicles, named as microparticles (MPs), can be taken up by normal or cancerous cells [19,20]. We have recently developed a natural drug delivery system with T-MPs, which can efficiently kill tumor cells without adverse side effects [21].…”

Macrophages transfer antigens to dendritic cells by releasing exosomes containing dead‐cell‐associated antigens partially through a ceramide‐dependent pathway to enhance CD4+ T‐cell responses

“…[1][2][3][4][5] In recent years, much attention has been paid to the role of cross-talk between macrophages (Mφs) and dendritic cells (DCs) in maintaining homeostasis or inducing a protective immune response under physiological or pathological conditions, respectively. [6][7][8] During the development of multicellular organisms, a controlled and programmed form of cell death is indispensable. Therefore, phagocytes must constantly remove apoptotic cells for normal homeostasis and tissue turnover, as the conversion of excessive apoptotic cells to secondary necrotic dead cells would induce inflammation or autoimmunity.…”