A United spokesman, Ken Ramsden, said: "We have not bought the club and this is not a takeover move. We have simply come to an agreement with them whereby we can send players to play in their team and gain experience and the situation will work vice versa."
United have already sent Danny Higginbotham, a reserve defender, to Belgium.
Talk that United will use the arrangement to sign non-EU nationals and allow them to gain Belgian citizenship and therefore avoid the need for a work permit when they sign for United was rejected by Ramsden.
Antwerp's secretary, Paul Bistiaux, described the deal as case of his club having to "face reality. He said: "The smaller clubs have to align themselves with the big ones to survive."
Antwerp in not the only Belgian club to have been approached. Germinal Ekeren, a small First Division club, is in talks with Ajax over a possible co-operation pact.
Gordon Taylor, the chairman of the Professional Footballers' Association, believes United's link-up could damage the English game. "If this link- up ends with more foreign players coming into the game, then the young Michael Owens and David Beckhams may not be such a priority in future," he said.
Fifa, football's world governing body, and Uefa, the European body, are concerned about such deals effectively turn smaller leagues and clubs into pawns for the bigger ones.
Fritz Ahlstrom, a spokesman for Uefa, expressed reservations about the deal. "In principle, we don't like it," he said. "What happens if Antwerp develop key players, and then is forced to let them go to sit on the bench in Manchester?"
But Ferguson said: "This is just part of the expansion plan," Ferguson said. "There will be deals with clubs in Australia, Ireland and Sweden." He did not elaborate.