Bacteria-instructed B cells cross-prime naïve CD8+ T cells triggering effective cytotoxic responses.

In addition to triggering humoral responses, conventional B cells have been described in vitro to cross-present exogenous antigens activating naïve CD8+ T cells. Nevertheless, the way B cells capture these exogenous antigens and the physiological roles of B cell-mediated cross-presentation remain poorly explored. Here, we show that B cells capture bacteria by trans-phagocytosis from previously infected dendritic cells (DC) when they are in close contact. Bacterial encounter "instructs" the B cells to acquire antigen cross-presentation abilities, in a process that involves autophagy. Bacteria-instructed B cells, henceforth referred to as BacB cells, rapidly degrade phagocytosed bacteria, process bacterial antigens and cross-prime naïve CD8+ T cells which differentiate into specific cytotoxic cells that efficiently control bacterial infections. Moreover, a proof-of-concept experiment shows that BacB cells that have captured bacteria expressing tumor antigens could be useful as novel cellular immunotherapies against cancer. © 2023 The Authors. Published under the terms of the CC BY NC ND 4.0 license.

Citation

Raquel García-Ferreras, Jesús Osuna-Pérez, Guillermo Ramírez-Santiago, Almudena Méndez-Pérez, Andrés M Acosta-Moreno, Lara Del Campo, María J Gómez-Sánchez, Marta Iborra, Beatriz Herrero-Fernández, José M González-Granado, Francisco Sánchez-Madrid, Yolanda R Carrasco, Patricia Boya, Nuria Martínez-Martín, Esteban Veiga. Bacteria-instructed B cells cross-prime naïve CD8+ T cells triggering effective cytotoxic responses. EMBO reports. 2023 Jul 05;24(7):e56131

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PMID: 37184882

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