Oral administration of an antigenic synthetic lipopeptide (MAP-P3C) evokes salivary antibodies and systemic humoral and cellular responses.

Parenteral immunization with a tetravalent multiple antigen peptide (MAP) containing a gp120 sequence coupled to a synthetic lipophilic moiety (MAP-P3C) has been previously found to produce systemic antibody and cellular responses in mice. This study demonstrates that oral administration of MAP-P3C induced IgA antibodies in mucosal secretions and protein-specific IgG in the sera of the immunized mice. Moreover, intragastric delivery of MAP-P3C generated systemic T-lymphocyte stimulation and specific cytotoxic T-lymphocyte (CTL) activity. The CTL response was eliminated by treatment with CD8-specific antibody plus complement and was MHC class I-restricted. Therefore, presentation of lipid-linked synthetic peptides to the intestinal mucosal surface is effective in initiating humoral and cellular immunity both at mucosal sites and systemically.