Carbon nanotubes significantly enhance the biological activity of CpG ODN in chickens

Abstract

Graphical abstract Figure. No caption available. ABSTRACT Synthetic unmethylated cytidine‐phosphate‐guanosine oligodeoxynucleotides (CpG ODN) is an effective immune stimulant in chicken. To be effective CpG dosage requirement is high. High dosage increases cost of treatment and introduces toxicity. A delivery system using multi‐walled carbon nanotubes (MWCNT) is utilized in this study to aid in lowering the effective dose of the immune stimulant. CpG ODNs were attached non‐covalently in different ways to multi‐walled carbon nanotubes (MWCNT). We assessed and selected an appropriate linking method of CpG ODN with MWCNT followed by cellular uptake studies to establish that MWCNT‐conjugated CpG ODNs were delivered better than free CpG ODNs into the cell. It was observed that MWCNT‐conjugated CpG ODNs were equally effective in priming the cells in vitro at 1000‐fold less concentration than free CpG ODN. In vivo studies revealed that a significantly lower dose of CpG ODN, when given subcutaneously, was enough to protect chickens from a lethal challenge of bacteria. The mechanism of immune stimulation was examined by in vivo cell recruitment and in vitro cytokine production studies. MWCNT‐conjugated CpG ODNs are significantly more efficacious and less toxic than free CpG ODN to qualify as a potential immune stimulant.