The antibody doctors administered to U.S. President Donald Trump for his COVID-19 infection was developed using human cells acquired from aborted fetal tissue, a practice that has been repeatedly condemned by the White House and anti-abortion organizations.

The vaccine - touted Wednesday evening as a "cure" for the highly-contagious coronavirus - is a monoclonal antibody combination developed by Regeneron Pharmaceuticals. Trump was given an 8-gram inoculation under a "compassionate use" exemption when the president was hospitalized over the weekend after being diagnosed with the disease.

Regeneron's antibody cocktail is still undergoing extensive clinical tests and is not yet approved by the U.S. Food and Drug Administration. Trump was one of the first 10 recipients being treated with the "wonder" drug. There is currently no cure for COVID-19.

Trump has never been timid in praising Regeneron's experimental drug after testing positive for the coronavirus last week. "I think this was a blessing from God that I caught the virus, I think it's a blessing in disguise," CBS News quoted the president as saying in a video. Trump, who said he heard about Regeneron's drug, said "Let me take it...and it's incredible the way it worked."

But the process in which the vaccine was developed contradicts the Trump administration's stance on stem cell studies. The Republican bloc platform bluntly denounces embryonic stem cell development and calls for the scrapping of government funding for its research.

Last year, the Trump administration withdrew its financial assistance for government health experts working on embryonic stem cell studies, affecting around $31 million in research, Science Magazine reported.

A Regeneron representative Thursday disclosed that the treatment's effectiveness was tested in a science facility using HEK 293T cells which were originally obtained from the kidney tissue of an aborted fetus in the Netherlands in the 1970s.

The development of Regeneron's antibody mixture is backed by a $450 million grant from the U.S. Biomedical Advanced Research and Development Authority.