Researchers Read the Sugary ‘Language’ on Cell Surfaces
When Pascal Gagneux envisions malaria parasites and other pathogens interacting with the surfaces of a host’s cells, he pictures a miniature rainforest with pathogenic particles flying overhead like colorful birds. The canopy consists of branching sugary molecules that adorn the surface of the cell. “If you’re a malaria parasite, you’re landing on a human red blood cell,” and “the first ‘leaves’ that you touch” are sugars called sialic acids, said Gagneux, an evolutionary biologist at the University of California, San Diego.
His ecological view of that interaction is rooted in his previous field work studying wild chimpanzee behavior in the dense West African forests. During those treks, he began to ask himself: “Why is it that humans and chimpanzees, who share so much of the same DNA, don’t deal with diseases the same way?”
“Diseases that give you and me the sniffles will actually kill chimpanzees,” he explained. But the opposite is also true. Chimps are not susceptible to influenza A, and HIV infections turn lethal in humans but stay mild in chimps. The malaria parasites that kill humans can’t infect chimps, and vice versa. This odd selectivity is not peculiar to primates — there are countless examples of pathogens devastating certain host species but not others.
