RÉSUMÉ
In a recent paper in Nature, Park et al. propose a mechanism through which intestinal dysbiosis compromises the efficacy of immunotherapy targeting the PD-L1/PD-1 interaction. Dysbiosis may upregulate a pair of checkpoint molecules, i.e. PD-L2 interacting with RGMb. Antibodies targeting PD-L2/RGMb can restore responses to PD-1 blockade in the context of dysbiosis.
Sujet(s)
Dysbiose , Récepteur-1 de mort cellulaire programmée , Humains , Immunothérapie/effets indésirables , Transduction du signal , Résistance aux substances , Microbiome gastro-intestinalRÉSUMÉ
Antibiotics (ABX) compromise the efficacy of programmed cell death protein 1 (PD-1) blockade in cancer patients, but the mechanisms underlying their immunosuppressive effects remain unknown. By inducing the down-regulation of mucosal addressin cell adhesion molecule 1 (MAdCAM-1) in the ileum, post-ABX gut recolonization by Enterocloster species drove the emigration of enterotropic α4ß7+CD4+ regulatory T 17 cells into the tumor. These deleterious ABX effects were mimicked by oral gavage of Enterocloster species, by genetic deficiency, or by antibody-mediated neutralization of MAdCAM-1 and its receptor, α4ß7 integrin. By contrast, fecal microbiota transplantation or interleukin-17A neutralization prevented ABX-induced immunosuppression. In independent lung, kidney, and bladder cancer patient cohorts, low serum levels of soluble MAdCAM-1 had a negative prognostic impact. Thus, the MAdCAM-1-α4ß7 axis constitutes an actionable gut immune checkpoint in cancer immunosurveillance.
