Detection and Characterization of Functional T-Cell Epitopes on the Structural Proteins VP2, VP3, and VP4 of Foot and Mouth Disease Virus O1 Campos

Abstract

Foot and mouth disease virus (FMDV) is the cause of a widespread infectious disease affecting cloven-hoofed animals. It is controlled by vaccination with immune-inactivated virus grown in tissue culture. However, peptide vaccines represent a safer alternative to the current virus-inactivated immunogens. Their design requires the identification and evaluation of the sequences recognized by T- and B-lymphocytes. Four structural proteins, VP1, VP2, VP3, and VP4, comprise the viral capsid of the FMDV, but only VP1 has been extensively studied regarding the existence of relevant T-cell epitopes. Here, we utilize a murine model to present a functional T-cell epitope mapping on the complete sequences of VP2, VP3, and VP4 of FMDV O1 Campos. We used two in vitro assays to describe 13 amino acid sequences, each one of them including at least one T-cell epitope. The in vivo T-cell helper function of these sequences was studied in an adoptive cell-transfer assay in mice. Immunization experiments with a fusion peptide containing one of the sequences characterized were also done comparing the helper activity of this sequence with other T-cell epitopes included in the major immunogenic region of VP1.