In a skillet, saute onion and celery in butter until tender. In a large bowl, combine the bread cubes, egg and water. Stir in the onion mixture, poultry seasoning, salt and pepper; set aside.
In another large bowl, combine the egg, milk, bread crumbs and salt. Crumble beef over mixture and mix well. Pat two-thirds of the meat mixture onto the bottom and up the sides to within 3/4 in. of the top of a 9x5-in. loaf pan. Spoon filling into meat shell; cover top with remaining meat mixture and seal edges.
Bake at 350° for 1 hour or until meat is no longer pink; drain. Let stand for 10 minutes before serving.