In UCB, Inc. v. Yeda Research and Development Co., Ltd., Appeal No. 2015-1957, the Federal Circuit held that prosecution estoppel can apply even absent narrowing of a particular proposed claim. 

While generic claim terms are construed in light of what is known in the art, the Federal Circuit held that a patent applicant cannot later obtain claims to subject matter that was requested during prosecution, rejected by the Examiner, and then withdrawn by the applicant.  The Federal Circuit agreed with the district court’s claim construction, which narrowed the scope of a generic term to specific species from the specification, because the applicant had withdrawn claims directed to additional species during prosecution.