A complementary DNA (cDNA) with SEQ ID NO: 1 which encodes an immunogenic fragment of major outer sheath protein (Msp) of Treponema denticola.L'invention concerne un ADN complémentaire (ADNc) à SEQ ID NO : 1 qui code un fragment immunogène de la protéine de gaine externe principale (Msp) de Treponema denticola.