Purpose. To determine the effect of unmethylated oligodeoxynucleotides containing bacterial CpG motifs (CpG ODN) on the induction of rat tear IgA antibody responses. Methods. Rats were immunized intranasally with either soluble dinitrophenylated bovine serum albumin (DNP-BSA) or poly(lactide-co-glycolide) (PLG) encapsulated DNP-BSA in combination with CpG ODN. The animals received two immunizations 21 days apart. Following the second immunization, tear, saliva and serum samples were collected for 28 days and analyzed for antigen specific antibodies. Tear IgA, saliva IgA and serum IgG antibody concentrations were determined by ELISA. Results. Co-administration of CpG ODN with either soluble or encapsulated antigen resulted in significantly elevated levels of both tear and salivary IgA antibodies as well as levels of serum IgG antibodies. Microencapsulated DNP-BSA plus CpG ODN elicited higher levels of IgA antibodies in tears than did soluble antigen plus CpG ODN. Conclusions. CpG ODN is an effective mucosal immune modulator for enhancing rat tear IgA antibody responses to both soluble and microencapsulated antigens.
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