PORTLAND — AIDS activists staged a protest Monday on behalf of an operating room nurse who is suing a health-care clinic that allegedly fired him for having the virus that causes AIDS.

The York County nurse, whose name isn’t used in the lawsuit, contends his dismissal by Orthopaedic Associates of Portland was illegal discrimination against someone with a physical disability. The nurse apparently is the first health-care worker in the state to file such a suit.

On Monday morning, seven members of the activist group ACT UP put up protest posters on behalf of the nurse at the offices of Orthopaedic Associates and padlocked one of the building’s entrances.

“It was done before anybody got there,” said Richard G. Moon, the clinic’s attorney. “We don’t intend to take any action if this is all that’s been done. We would hope that they would view this in an objective way and let the court process proceed.”

The registered nurse wants his job back and an unspecified amount in damages, said Jed Davis, the nurse’s attorney. Davis said the nurse doesn’t pose a health risk as long as he takes proper precautions.

But Moon contended the nurse was an unnecessary risk because outpatient surgery at the clinic involves the use of sharp instruments such as saws, chisels and drills.

The deadly disease AIDS is spread primarily through sexual contact and sharing of intravenous needles contaminated with blood that contains the virus.