A defrocked Philadelphia priest pleaded guilty Thursday to a sex-abuse charge, just days before a landmark priest abuse trial is set to start.

Edward Avery, 69, pleaded guilty to involuntary deviate sexual intercourse and conspiracy to endanger the welfare of a child. He was immediately sentenced to 2ยฝ to five years in prison and was ordered to surrender within 10 days.

The charges stemmed from Avery's abuse of an altar boy at St. Jerome's Parish in northeast Philadelphia.

Two other church officials will still go on trial. One is Monsignor William Lynn, the first U.S. church official ever charged with endangering children for allegedly failing to oust accused predators from the priesthood.

Avery was at the parish despite a credible 1992 complaint that led him to undergo psychological testing at an archdiocesan-run psychiatric hospital, according to a grand jury report. He was pulled from his parish, put on a so-called "health leave" and then reassigned in 1993, the report said.

Avery's accuser said he was passed around by Avery, another priest and his Catholic school teacher in 1998-99.

"When Mass was ended, Fr. (Edward) Avery took the fifth-grader into the sacristy, turned on the music, and ordered him to perform a 'striptease' for him. ... When they were both naked, the priest had the boy sit on his lap and kissed his neck and back, while saying to him that God loved him," the grand jury report alleged. Oral sex and digital penetration followed, the report said.