Immunogenicity of apoptotic cells in vivo: Role of antigen load, antigen-presenting cells, and cytokines

Anna Ronchetti, Patrizia Rovere, Giandomenica Iezzi, Giacomo Galati, Silvia Heltai, Maria Pia Protti, Maria Paola Garancini, Angelo A. Manfredi, Claudio Rugarli, Matteo Bellone

Research output: Contribution to journalArticlepeer-review

Abstract

Apoptosis allows the clearance of unwanted cells from living tissues without causing inflammation. Processing of phagocytosed apoptotic cells yields Ags that access the cytosol and the MHC class I pathway of engulfing cells and are recognized by Ag-specific CTL. We show here that injection of apoptotic RMA cells, a syngeneic T cell lymphoma, into C57BL/6 mice results in priming of a functional and long-lasting tumor-specific immune response. Cross-priming of CTLs by apoptotic cells requires CD4+ T cell help. Apoptotic cells, however, are at least 20-fold less immunogenic than nonreplicating live cells. Immunogenicity of apoptotic cells is proportional to the number of cells injected, correlates with the serum concentration of IL-10 and IL-1α cytokines, and is enhanced in IL-10 knockout mice. Moreover, immunization with dendritic cells (DCs), but not macrophages (Mφ), pulsed with apoptotic cells primes tumor-specific CTLs and confers protection against a tumor challenge. Our findings demonstrate that tumor cells undergoing apoptosis are, though scarcely, immunogenic in vivo, outline the different roles of Mφ and DCs in the physiologic clearance of unwanted cells, and have implications in designing immunomodulating vaccines.

Original languageEnglish
Pages (from-to)130-136
Number of pages7
JournalJournal of Immunology
Volume163
Issue number1
Publication statusPublished - Jul 1 1999

ASJC Scopus subject areas

  • Immunology

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