Sorority Lockdown Over Ben Roethlisberger

Ben Roethlisberger's accuser may have dropped out of school, but her sorority is closing ranks. TMZ has learned the group's leaders issued sorority-wide marching orders ... including a mass Facebook takedown.

Sources at Georgia College & State University -- where the accuser was enrolled before the alleged incident -- tell us the accuser's sorority sisters have been ordered to take down each of their Facebook and Twitter accounts and refrain from wearing any clothing with the sorority letters until further notice.

We're told three members of the sorority's national office visited the campus sorority house to check in on the situation and may return later this week.