**4. Single epitope modification of HEVNP: HIV-1 GP120 P18 example**

As discussed earlier, insertion of the P18 peptide from the GP120 protein of HIV-1 results in a stable HEVNP that displays P18 on its surface (in the P domain after residue Y485). Additionally, the P18 insertion significantly lowers the immune system response against HEVNP. When the P18-HEVNP construct is orally inoculated into mice, it induces strong and specific cell-mediated and humoral responses in comparison to immunization with HEVNP [21]. After three rounds of oral immunization, the cell-mediated response includes the lysis of cytotoxic T lymphocytes (CTLs) in three immune system-associated organs. Similarly, humoral responses (IgG, IgA, and IgM induction) in the sera and intestinal fluids are detected by ELISA. These responses were generated by P18-HEVNP without the need for an external adjuvant coadministration.
