Structure-Based Design of Novel TLR7/8 Agonist Payloads Enabling an Immunomodulatory Conjugate Approach

Area of Science:

• Immunology
• Pharmacology
• Drug Discovery

Background:

• Toll-like receptor 7 (TLR7) and Toll-like receptor 8 (TLR8) pathways are crucial for innate and adaptive immunity.
• Dual activation of TLR7 and TLR8 pathways stimulates type I interferon and proinflammatory cytokines, enhancing antigen presentation.
• This immune stimulation promotes T-cell priming and is a promising strategy for antitumor immunity.

Purpose of the Study:

• To develop novel Toll-like receptor 7/8 (TLR7/8) dual agonists.
• To investigate agonists with varying ratios of TLR7 and TLR8 activity for antibody-drug conjugate (ADC) applications.
• To establish structure-activity relationships (SAR) for optimizing agonist design.

Main Methods:

• Design and synthesis of a novel series of TLR7/8 dual agonists.
• Evaluation of agonist activity through cytokine production assays in human whole blood.
• Structure-based drug design to guide SAR studies.

Main Results:

• The developed TLR7/8 dual agonists demonstrated functional activity, inducing cytokine production.
• Varying ratios of TLR7 and TLR8 activity were achieved in the novel agonist series.
• Structure-activity relationship studies provided insights for optimizing agonist properties.

Conclusions:

• Novel TLR7/8 dual agonists were successfully developed for potential use as payloads in antibody-drug conjugates.
• These agonists effectively stimulate immune responses relevant to enhancing antitumor immunity.
• The findings support the advancement of TLR7/8 agonists in cancer immunotherapy research.