Novel proteins from Lawsonia intracellularis are disclosed herein, as well as immunogenic fragments of the proteins. The invention further provides methods for immunization and vaccination, as well as immunogenic compositions that utilize the novel proteins or nucleic acids encoding the proteins.本發明揭示來自細胞內勞索尼亞氏菌之新穎蛋白質,以及該等蛋白質之免疫原性片段。本發明另外提供用於免疫及疫苗接種之方法,以及利用該等新穎蛋白質或編碼該等蛋白質之核酸的免疫原性組成物。