Chimeric NOD2 Mincle Agonists as Vaccine Adjuvants

Area of Science:

• Immunology
• Vaccinology
• Molecular Biology

Background:

• Improved vaccine adjuvants are crucial for enhancing vaccine efficacy.
• Targeting multiple pathogen recognition receptors (PRRs) with chimeric pathogen-associated molecular patterns (PAMPs) can augment immune responses.
• The macrophage inducible C-type lectin (Mincle) is a key PRR for adjuvant development, but effective chimeric adjuvants are lacking.

Purpose of the Study:

• To synthesize and evaluate novel chimeric Mincle adjuvants.
• To investigate the efficacy of conjugates containing PAMPs for Mincle and nucleotide-binding oligomerization domain 2 (NOD2).
• To assess the *in vitro* and *in vivo* immune responses and toxicity of these novel adjuvants.

Main Methods:

• Synthesis of Mincle adjuvant conjugates (MDP-C18Brar and MDP-C18Brar-dilipid) using a pH-sensitive oxyamine linker.
• Evaluation of cytokine production (*in vitro*) upon stimulation of immune cells.
• Assessment of T-cell-mediated immune responses and toxicity using ovalbumin (OVA) as a model antigen (*in vivo*).

Main Results:

• The synthesized conjugates effectively elicited Th1 and Th17 promoting cytokines *in vitro*.
• OVA-specific T-cell-mediated immune responses were significantly enhanced *in vivo* compared to coadministration.
• The chimeric adjuvants demonstrated reduced toxicity *in vivo*.

Conclusions:

• Novel chimeric Mincle adjuvants can be synthesized using pH-sensitive linkers.
• These conjugates enhance antigen-specific T-cell immunity and exhibit a favorable safety profile.
• This approach offers a promising strategy for developing next-generation vaccine adjuvants.