Research progress on the molecular mechanisms of PD-1 and LAG-3 synergy in regulating T cell exhaustion and immunotherapy

TL;DR

This paper reviews how PD-1 and LAG-3 work together to weaken T-cell function in tumors and explores how blocking both can improve cancer immunotherapy.

Contribution

The paper provides a systematic synthesis of PD-1/LAG-3 synergy mechanisms and dual blockade therapy advances.

Findings

PD-1 and LAG-3 synergistically suppress T-cell function through distinct signaling pathways.

Dual blockade with bispecific antibodies has shown clinical promise, including approval for melanoma.

Challenges remain in achieving consistent response rates and managing adverse events.

Abstract

PD-1 and LAG-3 are immune checkpoint molecules frequently co-expressed in the tumor microenvironment, where they synergistically drive T-cell exhaustion and immune escape. Dual blockade of these pathways represents a promising strategy to overcome immunotherapy resistance.

This review systematically synthesizes mechanistic studies on PD-1/LAG-3 synergy and summarizes preclinical and clinical advances in dual blockade therapies, with emphasis on bispecific antibodies and combination trial data.

PD-1 and LAG-3 cooperatively suppress T-cell function via complementary signaling pathways. Combined inhibition substantially restores antitumor immunity. A PD-1/LAG-3 bispecific antibody has been approved for melanoma, with numerous trials ongoing across other malignancies.

Despite demonstrated efficacy, challenges including variable response rates, resistance mechanisms, and immune-related adverse events remain. Future efforts should prioritize biomarker identification and regimen optimization to enable precision application of dual blockade.

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