Bats harbor dangerous viruses without becoming seriously ill — and a US research team may now know part of the reason: an immune system unlike that of any other mammal.
Two toolkits for antibodies
Antibodies are Y-shaped proteins made of two heavy and two light protein chains. In humans and every other known mammal, the heavy chains are built from a single set of genes. A team led by Hannah Frank of Tulane University now reports that vesper bats (family Vespertilionidae) instead carry two entirely separate gene systems for those heavy chains. In the big brown bat, one set holds 33 antibody genes, the other 99. The study appeared in the journal Science Advances.
More than 500 species affected
Vesper bats are the largest bat family of all — over 500 species. “We’ve never seen anything like this in a mammal before,” Frank is quoted as saying. “This completely changes our understanding of how mammalian immune systems can be organized.” The work was carried out at Tulane University together with Stanford University and the US Centers for Disease Control and Prevention.
Why it matters
The second gene toolkit gives the animals a completely new way to generate a wide variety of antibodies. The researchers suspect this could help explain why bats tolerate so many viruses without falling ill. That link is not yet proven — the functional role of the doubled system still has to be confirmed in further experiments. What is clear is that bats may reveal that immune systems can be built in fundamentally different ways than the textbooks have assumed.
Sources: Science Advances · ScienceDaily · Tulane University
