Targeting of Immune Cells by Dual TLR2/7 Ligands Suppresses Features of Allergic Th2 Immune Responses in Mice.

BACKGROUND

TLR ligands can promote Th1-biased immune responses, mimicking potent stimuli of viruses and bacteria.

AIM

To investigate the adjuvant properties of dual TLR2/7 ligands compared to those of the mixture of both single ligands.

METHODS

Dual TLR2/7 ligands: CL401, CL413, and CL531, including CL264 (TLR7-ligand) and PamCysK (TLR2-ligand), were used. Immune-modulatory capacity of the dual ligands with the individual ligands alone or as a mixture in mouse BMmDCs, BMmDC:TC cocultures, or BMCMCs was compared and assessed in naïve mice and in a mouse model of OVA-induced intestinal allergy.

RESULTS

CL413 and CL531 induced BMmDC-derived IL-10 secretion, suppressed rOVA-induced IL-5 secretion from OVA-specific DO11.10 CD4 TCs, and induced proinflammatory cytokine secretion . In contrast, CL401 induced considerably less IL-10 secretion and led to IL-17A production in BMmDC:TC cocultures, but not BMCMC IL-6 secretion, or IL-6 or TNF- production . No immune-modulating effects were observed with single ligands. All dual TLR2/7 ligands suppressed DNP-induced IgE-and-Ag-specific mast cell degranulation. Compared to vaccination with OVA, vaccination with the mixture CL531 and OVA, significantly suppressed OVA-specific IgE production in the intestinal allergy model.

CONCLUSIONS

Based on beneficial immune-modulating properties, CL413 and CL531 may have utility as potential adjuvants for allergy treatment.