Drugs used to treat serious diseases contain an animal molecule that can harm the health of some patients, according to a team led by Professor Ajit Varki. Sialic acids are in all mammals, but humans lack a specific type--Neu5Gc--that is found in many other mammals. Neu5Gc can enter the human body through modern biotech drugs that come from animal sources--and also through the consumption of red meat--and trigger an immune response that can have a damaging inflammatory effect in some individuals, the Sydney Morning Herald reports.
Humans used to make Neu5Gc, but lost the ability to do so roughly 2 million to 3 million years ago, according to Dr. Oliver Pearce, who has worked with Varki, in an interview last year. But all the cellular machinery is present to process this sugar as if it were natural. Researchers say that Neu5Gc still gets picked up by human epithelial cells and presented on their surface, but the immune system recognizes it as foreign and therefore dangerous.
"It's reasonable to suggest that for some patients who have problems with some drugs, this may be part of the reason why," says Varki who led the research published in the journal Nature Biotechnology. "Our findings may be relevant to improving the half-life, efficacy and immunogenicity of glycoprotein therapeutics," the researchers say. The immune response generated by Neu5Gc could help explain relationships between certain foods and diseases linked to inflammation, including cancer and heart disorders, says Varki.