CpG DNA is an effective oral adjuvant to protein antigens in mice

We have previously reported that synthetic oligodeoxynucleotides containing immunostimulatory CpG motifs (CpG ODN) are potent adjuvants to protein adm inistered by intramuscular (IM) injection or intranasal (IN) inhalation to BALB/c mice. Herein, we have evaluated oral delivery of CpG ODN with purifi ed hepatitis B surface antigen (HBsAg) or tetanus toroid (TT) to determine its potential as an adjuvant to oral vaccines. CpG ODN augmented systemic ( IgG in plasma, CTL, T-cell proliferation) and mucosal (IgA in lung, vaginal or gut washes, feces and saliva) immune responses against both antigens. C pG stimulated both T-helper type 1 (Th1) (CTL, IgG2a) and Th2 (IgG1, IgA) r esponses when delivered orally. Results from this study indicate that stimu latory CpG ODN may be effective as an adjuvant with oral vaccines. (C) 2000 Elsevier Science Ltd. All rights reserved.