Bill Cosby's alma mater has severed ties with the actor and comedian following a series of sexual assault allegations against him.

The University of Massachusetts-Amherst announced Wednesday that Cosby has stepped down from his position as honorary co-chairman of a $300 million fundraising campaign at the university's request.

"He no longer has any affiliation with the campaign nor does he serve in any other capacity for the university," University spokesman Edward Blaguszewski told the Boston Globe.

The announcement followed a request by Massachusetts Attorney General Martha Coakley for UMass to end its relationship with the entertainer.

"At a time when the state is focused on prevention and response to sexual assaults on campus, allowing Mr Cosby to continue to represent our state university sends the exact wrong message," a letter from Coakley to the university read.

"Although Mr Cosby has not been criminally charged nor convicted for these actions, the UMass community has discretion to determine who should be the 'face' of the university at any time.

"I believe the volume and disturbing nature of these allegations has reached a point where Mr Cosby should no longer have a formal role at UMass, nor be involved in its fund-raising efforts, unless or until Mr Cosby is able to satisfactorily respond to these allegations."

Cosby received a Master's degree in Education from UMass-Amherst in 1972, and a doctorate in Education in 1976. Records indicate that Cosby and his wife, Camille, have given between $250,000 and $499,999 to the university, and Cosby performed at a 2004 benefit that raised $1.5 million for the school.

At least 19 women have accused Cosby of sexually assaulting or drugging them, with the first woman coming forward in 2005. Cosby has not been charged in any of the cases, and settled the 2005 case out of court.