Development of CpG-Oligodeoxynucleotides for Effective Activation of Rabbit TLR9 Mediated Immune Responses

Tsung-Hsien Chuang,Chiun-Jye Yuan,Li-Chung Hsu,Ping-Hui Tseng,Chao-Yang Lai,Hidde L Ploegh

doi:10.1371/journal.pone.0108808

Abstract

CpG-oligodeoxynucleotides (CpG-ODN) are potent immune stimuli being developed for use as adjuvants in different species. Toll-like receptor 9 (TLR9) is the cellular receptor for CpG-ODN in mammalian cells. The CpG-ODN with 18–24 deoxynucleotides that are in current use for human and mouse cells, however, have low activity with rabbit TLR9. Using a cell-based activation assay, we developed a type of CpG-ODN containing a GACGTT or AACGTT motif in 12 phosphorothioate-modified deoxynucleotides with potent stimulatory activity for rabbit TLR9. The developed CpG-ODN have higher activities than other developed CpG-ODN in eliciting antigen-nonspecific immune responses in rabbit splenocytes. When mixed with an NJ85 peptide derived from rabbit hemorrhagic disease virus, they had potent activities to boost an antigen-specific T cell activation and antibody production in rabbits. Compared to Freund’s adjuvant, the developed CpG-ODN are capable of boosting a potent and less toxic antibody response. The results of this study suggest that both the choice of CpG-motif and its length are important factors for CpG-ODN to effectively activate rabbit TLR9 mediated immune responses.

Highlights

Toll-like receptors (TLRs) are a family of pattern recognition receptors
CpG-ODN have been investigated as immunological adjuvant in a wide variety of animals and fish [22,23,24], previous studies have shown that CpG-ODN with 18–24 deoxynucleotides in current use for the activation of human or mouse cells have low activity to rabbit Toll-like receptor 9 (TLR9) [27,28]
We were curious to learn how a CpG-ODN would act on rabbit TLR9 (rabTLR9) if the CpG-ODN contained both the GTCGTT and GACGTT motifs

Summary

Introduction

Toll-like receptors (TLRs) are a family of pattern recognition receptors. These receptors are essential for innate immune cells to detect a wide variety of pathogen-associated molecular patterns – such as those of lipids, lipoproteins, glycans, proteins, and nucleic acids – to elicit host immune responses. CpG-ODN containing the GTCGTT motif generate higher immune responses in humans and various domestic animals than those with the GACGTT motif; in contrast, the latter are more potent in activation of murine cells [9,10,11,12].

Results

Conclusion