Adjuvant effect of a 14-member macrolide antibiotic on DNA vaccine

Macrolide antibiotics have unique immunomodulatory actions apart from their antimicrobial properties. We examined the effect of erythromycin (EM), a 1 4-member macrolide, on the immune response to a DNA vaccine that induces a T-helper-1 (Th1)-biased immune response through a Th1-promoting adjuvant ef fect of unmethylated CPG motifs within plasmid DNA. EM enhanced Th1 respons es in plasmid DNA-immunized mice as measured by antigen-specific IgG2a anti body production, interferon-gamma production by antigen-specific CD4(+) T c ells, and cytotoxic T lymphocyte responses. EM augmented the accessory cell activity of unmethylated CpG DNA-stimulated antigen-presenting cells (APCs ), suggesting that EM enhances Th1 responses to a DNA vaccine, possibly thr ough augmentation of accessory cell activity of APCs stimulated with CPG mo tifs within plasmid DNA, (C) 1999 Academic Press.