Algae Virus Can Infect Mammalian Cells

This image shows a cell in blue with the ATCV-1 viral particles; it's the only known virus to infect both algal and mammalian cells. University Communications/University of Nebraska-Lincoln

It's relatively uncommon for viruses to infect organisms from different kingdoms of life. But now, scientists have determined that a particular virus known to infect green algae can also infect mouse macrophages, a type of immune cell. University of Nebraska-Lincoln researcher David Dunigan says that it's the only known virus to be able to infect algal and mammalian cells.

In a study published this month in the Journal of Virology, Dunigan and his colleagues found that the virus, ATCV-1, was capable of entering and infecting mouse macrophages, and increasing in mass, suggesting that it was making copies of itself. Following introduction of the virus, the scientists witnessed other cellular changes consistent with infection including cell death, Dunigan says.

Vincent Racaniello, a virologist at Columbia University who wasn't involved in the paper, says finding a virus that can infect organisms in different kingdoms is quite unusual and "not something you see every day, though it's not unheard of."

The new study complements a paper Dunigan co-authored last year in Proceeding of the National Academy of Sciences, which discovered that DNA sequences from the virus could be found in the throat swabs of 40 of 92 healthy participants sampled. The team found that people who harbored the virus's DNA scored lower on two tests of cognitive abilities, leading to some speculation the virus could be to blame. But that hasn't been proven, and the correlation could be due to one of many confounding factors, such as diet or genetics, to name two.

Furthermore, it's possible the virus could've been infecting other organisms in people's throat—perhaps some microorganism (like bacteria) more similar to algae than humans. But the new paper shows that the virus can infect macrophages from a mouse, which aren't that different from humans—so perhaps the virus was infecting humans after all. But that remains to be definitively shown; in attempt to learn more, the team is now trying to isolate the virus from samples of human cells, Dunigan says.

The study and its precursor are "kind of tantalizing" and bring up a lot of fascinating questions, says Racaniello, who's excited to see where this line of inquiry goes in the future.