PDL1-targeted vaccine exhibits potent antitumor activity by simultaneously blocking PD1/PDL1 pathway and activating...

Area of Science:

• Immunology
• Oncology
• Vaccine Development

Background:

• Immune checkpoint blockade therapy is effective in a subset of patients, necessitating alternative immunotherapeutic strategies.
• Programmed death ligand 1 (PDL1) plays a crucial role in immune evasion by tumors.
• Existing PDL1-targeting therapies may not be effective for all cancer patients.

Purpose of the Study:

• To develop and evaluate a novel "two-in-one" cancer vaccine targeting PDL1.
• To assess the vaccine's ability to block the PD1/PDL1 pathway and activate antitumor immunity.
• To investigate the vaccine's impact on the tumor microenvironment and its potential as an alternative immunotherapy.

Main Methods:

• Development of a PDL1-NitraTh vaccine comprising the extracellular domain of PDL1 and a nitrated T cell epitope.
• Evaluation of the vaccine's capacity to elicit PDL1-specific humoral and cellular immunity.
• Assessment of the vaccine's antitumor activity, effects on tumor-infiltrating lymphocytes, regulatory T cells (Tregs), and PDL1 expression in tumor tissues.

Main Results:

• The PDL1-NitraTh vaccine effectively broke immune tolerance to PDL1, inducing specific humoral and cellular immune responses.
• Treatment with the PDL1-NitraTh vaccine demonstrated potent antitumor activity.
• Vaccine immunization led to increased tumor-infiltrating lymphocytes, decreased Treg proportion in tumors, and induced PDL1 upregulation within tumor tissues, enhancing therapeutic effects.

Conclusions:

• The PDL1-NitraTh vaccine represents a novel immunotherapeutic strategy with potent antitumor activity.
• This vaccine effectively targets PDL1, overcomes immune tolerance, and remodels the tumor microenvironment.
• PDL1-targeted vaccination may offer a viable alternative for patients resistant to PDL1 antibody drugs.