Search

Reversing CD8+ T cell dysfunction is crucial in treating chronic hepatitis B virus (HBV) infection, yet specific molecular targets remain unclear. Our study analyzed co-signaling receptors during hepatocellular priming and traced the trajectory and fate of dysfunctional HBV-specific CD8+ T cells. Early on, these cells upregulate PD-1, CTLA-4, LAG-3, OX40, 4-1BB, and ICOS. While blocking co-inhibitory receptors had minimal effect, activating 4-1BB and OX40 converted them into antiviral effectors. Prolonged stimulation led to a self-renewing, long-lived, heterogeneous population with a unique transcriptional profile. This includes dysfunctional progenitor/stem-like (T SL) cells and two distinct dysfunctional tissue-resident memory (T RM) populations. While 4-1BB expression is ubiquitously maintained, OX40 expression is limited to T SL. In chronic settings, only 4-1BB stimulation conferred antiviral activity. In HBeAg+ chronic patients, 4-1BB activation showed the highest potential to rejuvenate dysfunctional CD8+ T cells. Targeting all dysfunctional T cells, rather than only stem-like precursors, holds promise for treating chronic HBV infection. [Display omitted] • Hepatocellular priming induces key co-signaling receptors in dysfunctional CD8+ T cells • While checkpoint inhibition fails, 4-1BB and OX40 activation restores T cell function • Prolonged Ag stimulation yields a self-renewing, long-lived, heterogeneous T cell pool • In chronic settings, only 4-1BB remains effective among further co-receptor modulation In this study, we traced the trajectory and fate of dysfunctional HBV-specific CD8+ T cells and analyzed the modulation of co-signaling receptors following hepatocellular priming. We identified 4-1BB agonism as the most promising strategy to convert these cells into antiviral effectors for treating chronic HBV infections. [ABSTRACT FROM AUTHOR]

Kupffer cells (KCs) are highly abundant, intravascular, liver-resident macrophages known for their scavenger and phagocytic functions. KCs can also present antigens to CD8+ T cells and promote either tolerance or effector differentiation, but the mechanisms underlying these discrepant outcomes are poorly understood. Here, we used a mouse model of hepatitis B virus (HBV) infection, in which HBV-specific naive CD8+ T cells recognizing hepatocellular antigens are driven into a state of immune dysfunction, to identify a subset of KCs (referred to as KC2) that cross-presents hepatocellular antigens upon interleukin-2 (IL-2) administration, thus improving the antiviral function of T cells. Removing MHC-I from all KCs, including KC2, or selectively depleting KC2 impaired the capacity of IL-2 to revert the T cell dysfunction induced by intrahepatic priming. In summary, by sensing IL-2 and cross-presenting hepatocellular antigens, KC2 overcome the tolerogenic potential of the hepatic microenvironment, suggesting new strategies for boosting hepatic T cell immunity. [Display omitted] • KCs are required for in vivo reinvigoration of intrahepatically primed T cells by IL-2 • KCs respond to IL-2 and cross-present hepatocellular Ags • Single-cell RNA-seq identifies two distinct populations of KCs • KC2s have enriched IL-2 sensing machinery and Ag presentation capacity De Simone et al. delineate the mechanisms by which hepatocellularly primed HBV-specific CD8+ T cells acquire antiviral effector functions following IL-2 administration. These mechanisms rely on KCs and, in particular, on a hitherto unidentified KC subset, referred to as KC2, that is poised to respond to IL-2 and cross-present viral antigens. [ABSTRACT FROM AUTHOR]