PMA induces vaccine adjuvant activity by the modulation of TLR signaling pathway.

Dool-Ri Oh,Jong-Ro Kim,Young Ran Kim,Sunoh Kim,Joon Haeng Rhee,In-Kyu Park,Hu Won Kang,Won Keun Oh

doi:10.1155/2014/406514

Abstract

Toll-like receptor (TLR) ligands are being developed for use as vaccine adjuvants and as immunomodulators because of their ability to stimulate innate and adaptive immune responses. Flagellin, a TLR5 ligand, was reported to show potent mucosal vaccine adjuvant activity. To identify ligands that potentiate the adjuvant activity of flagellin, we screened a plant library using HEK293T cells transiently cotransfected with phTLR5 and pNF-κB-SEAP plasmids. The 90% EtOH extract from Croton tiglium showed significant NF-κB transactivation in a TLR5-independent manner along with the increase of a flagellin activity. We have studied to characterize an active component from Croton tiglium and to elucidate the action mechanisms. Phorbol 12-myristate 13-acetate (PMA) was isolated as an active component of Croton tiglium by activity-guided fractionation, column chromatography, HPLC, NMR, and MS. PMA at a range of nM induced PKC-dependent NF-κB activation and IL-8 production in both TLR5− and TLR5+ assay systems. In in vivo mouse vaccination model, PMA induced antigen-specific IgG and IgA antibody responses and increased IL-12 production corresponding to T cell responses in spleen lymphocytes. These results suggest that PMA would serve as an efficacious mucosal vaccine adjuvant.

Highlights

Toll-like receptors (TLRs) play crucial roles in innate immunity and can contribute to the development of appropriate adaptive immune responses [1, 2]
We reported that a Vibrio vulnificus flagellin B (FlaB) showed strong mucosal vaccine adjuvant activity [9] and enhanced tumor-specific CD8+ T cell immune responses through TLR5 stimulation in a therapeutic cancer vaccine model [10]
The present study demonstrates the vaccine adjuvant effect of Phorbol 12-myristate 13-acetate (PMA) isolated from Croton tiglium

Summary

Introduction

Toll-like receptors (TLRs) play crucial roles in innate immunity and can contribute to the development of appropriate adaptive immune responses [1, 2]. 13 members of TLR family have been identified in mammals [3,4,5], and TLRs received special attention as potent adjuvant receptors [6]. We reported that a Vibrio vulnificus flagellin B (FlaB) showed strong mucosal vaccine adjuvant activity [9] and enhanced tumor-specific CD8+ T cell immune responses through TLR5 stimulation in a therapeutic cancer vaccine model [10]. FlaB combined with TNFα and IFNα was reported to generate potent dendritic cells which produce functionally active cytotoxic T lymphocytes [11]. To identify ligands that potentiate vaccine adjuvant activity of flagellin, we screened a plant extract library using HEK293T cells transiently cotransfected with phTLR5 and pNF-κBSEAP plasmids. The 90% EtOH extract from Croton tiglium L. Croton tiglium is a plant grown in tropical and subtropical

Methods

Results

Conclusion