To overcome limitations of classical dendritic cell (cDC) immunotherapy, Mysore et al. generated neutrophil-derived APCs (nAPC) with DC properties. Neutrophil to nAPC conversion required FcγR-mediated endocytosis of Ag:Ab complexes or an anti-FcγRIIIB-Ag conjugate, resulting in comparable T cell activation to cDCs, migration to draining lymph nodes, and CD8+ T cell-dependent antitumor immunity in mice. Autologous T cell activation occurred with nAPCs generated from malignant neoantigen-expressing neutrophils obtained from myeloid tumors, suggesting translational potential. In lupus patients, blood nAPCs correlated with disease activity.
Contributed by Katherine Turner
ABSTRACT: Classical dendritic cells (cDC) are professional antigen-presenting cells (APC) that regulate immunity and tolerance. Neutrophil-derived cells with properties of DCs (nAPC) are observed in human diseases and after culture of neutrophils with cytokines. Here we show that FcγR-mediated endocytosis of antibody-antigen complexes or an anti-FcγRIIIB-antigen conjugate converts neutrophils into nAPCs that, in contrast to those generated with cytokines alone, activate T cells to levels observed with cDCs and elicit CD8+ T cell-dependent anti-tumor immunity in mice. Single cell transcript analyses and validation studies implicate the transcription factor PU.1 in neutrophil to nAPC conversion. In humans, blood nAPC frequency in lupus patients correlates with disease. Moreover, anti-FcγRIIIB-antigen conjugate treatment induces nAPCs that can activate autologous T cells when using neutrophils from individuals with myeloid neoplasms that harbor neoantigens or those vaccinated against bacterial toxins. Thus, anti-FcγRIIIB-antigen conjugate-induced conversion of neutrophils to immunogenic nAPCs may represent a possible immunotherapy for cancer and infectious diseases.
