A real-time antibody-dependent cellular phagocytosis assay by live cell imaging.
J Immunol Methods
; 531: 113715, 2024 Aug.
Article
em En
| MEDLINE
| ID: mdl-38936465
ABSTRACT
Antibody-dependent cellular phagocytosis (ADCP) is a cellular process by which antibody-opsonized targets (pathogens or cells) activate the Fc receptors on the surface of phagocytes to induce phagocytosis, resulting in internalization and degradation of pathogens or target cells through phagosome acidification. Besides NK cells-mediated antibody-dependent cellular cytotoxicity (ADCC), tumor-infiltrated monocytes and macrophages can directly kill tumor cells in the presence of tumor antigen-specific antibodies through ADCP, representing another attractive strategy for cancer immunotherapy. Even though several methods have been developed to measure ADCP, an automated and high-throughput quantitative assay should offer highly desirable advantages for drug discovery. In this study we established a new ADCP assay to identify therapeutical monoclonal antibodies (mAbs) that facilitate macrophages phagocytosis of live target cells. We used Incucyte, an imaging system for live cell analysis. By labeling the live target cells with a pH sensitive dye (pHrodo), we successfully monitored the ADCP in real time. We demonstrated that our image-based assay is robust and quantitative, suitable for screening and characterization of therapeutical mAbs that directly kill target cells through ADCP. Furthermore, we found different subtypes of macrophages have distinct ADCP activities using both mouse and human primary macrophages differentiated in vitro. By studying various mAbs with mutations in their Fc regions using our assay, we showed that the variants with increased binding to Fc gamma receptors (FcγRs) have enhanced ADCP activities.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fagocitose
/
Macrófagos
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Anticorpos Monoclonais
Limite:
Animals
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Humans
Idioma:
En
Revista:
J Immunol Methods
Ano de publicação:
2024
Tipo de documento:
Article
País de afiliação:
Estados Unidos