Induction in mucosa of IgG and IgA antibodies against parenterally administered soluble immunogens

The induction of a mucosal immunity provides an additional principle of vac cination by preventing the entry of pathogens in the body. Albeit the fact that intensive research has been conducted on local vaccines, the major muc osal vaccine commercially available for human use remains the oral polio va ccine. We have previously demonstrated that parenteral vaccination in human s with tetanus toroid (TT) results in a genital immunoglobulin (IE)G antibo dy (Ab) response. Here, we show that injections of TT with no adjuvant indu ces an anti-TT response in the mucosal tissues of normal BALB/c mice. The r esponse is multiregional, involves both IgG and IgA isotypes, and is long-l asting. Similarly, injections of haptens coupled to TT or to other diffusib le proteins may induce mucosal Abs. These results led us to immunize normal BALB/c mice with a viral peptide coupled to TT by disulfide bridging. The hapten was a 17 amino acid peptide containing the ELDKWA sequence of human immunodeficiency virus (HIV)-1 gp41. A significant IgG and IEA At, response to the immunizing peptide was induced in various mucosal tissues despite t he presence of a suboptimal Ab response in the spleen. The results indicate that mucosal immunity to peptides that are candidates for human vaccinatio ns may be achieved by parenteral adjuvant-free immunization with peptide co upled to TT.