The immunogenicity of the tumor-associated antigen α-fetoprotein is enhanced by a fusion with a transmembrane domain.

Aim: To investigate the ability of recombinant modified vaccinia virus Ankara (rMVA) vector to induce an immune response against a well-tolerated self-antigen.
Methods: rMVA vectors expressing different form of α-fetoprotein (AFP) were produced and characterized. Naïve mice were vaccinated with MVA vectors expressing the AFP antigen in either a secreted, or a membrane-bound, or an intracellular form. The immune response was monitored by an IFNΓ ELISpot assay and antibody detection.
Results: Vaccination with the membrane-associated form of AFP induced a stronger CD8(+) T-cell response compared to the ones obtained with the MVA encoding the secreted or the intracellular forms of AFP. Moreover, the vaccination with the membrane-bound AFP elicited the production of AFP-specific antibodies.
Conclusions: The AFP transmembrane form is more immunogenic. Expressing a membrane-bound form in the context of an MVA vaccination could enhance the immunogenicity of a self-antigen.