Submitted to: Journal of Leukocyte Biology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/9/2001
Publication Date: N/A
Citation: Interpretive Summary: A novel approach to vaccination is the use of DNA coding for antigens that are targets of protective immune responses. Oligonucleotides including immunostimulatory sequences (ISS) including the motif CpG were previously shown to promote enhanced type 1 responses important for protection against intracellular pathogens. We engineered plasmid DNA to include ISS motifs and characterized at the molecular level their patterns of stimulation of bovine macrophages. The results indicate that such modified plasmids appear to effectively stimulate macrophages to secrete cytoquines that may be important for protection against intracellular pathogens.
Technical Abstract: The immunogenicity of DNA vaccines is partially attributable to the adjuvant properties of bacterial plasmid DNA (pDNA) for B lymphocytes and professional antigen presenting cells. In mice, modification of immunostimulatory sequences (ISS), including CpG motifs, in pDNA vectors or oligodeoxynucleotides can increase or decrease their adjuvant properties. ISS that stimulate optimal responses reportedly differ for murine and human leukocytes. We have previously characterized the mitogenic properties of oligodeoxynucleotides containing one AACGTT motif for bovine B lymphocytes. We now define cytokine responses by macrophages stimulated with pDNA engineered to contain an ISS comprising two AACGTT motifs. Macrophages activated with CpG-modified pDNA secreted significantly more IL-12, TNF-?, and NO than macrophages stimulated with unmodified pDNA or modified pDNA that contained nucleotides scrambled to remove CpG motifs. Engineered CpG-pDNA or CpG-oligodeoxynucleotides should be useful as vaccines or adjuvants to promote enhanced type 1 responses important for protection against intracellular pathogens.