It is a\u00a0mystery that has\u00a0puzzled scientists\u00a0for years.\u00a0How can the world’s only winged mammals\u00a0carry viruses that cause severe disease\u00a0while rarely becoming seriously ill themselves?<\/p>\n
Now researchers\u00a0at\u00a0Tulane University, with collaborators at Stanford University and the Centers for Disease Control,\u00a0may have found a reason.<\/p>\n
In a study\u00a0published in\u00a0Science Advances,\u00a0the research team\u00a0found that the world’s largest family of bats has two distinct copies of the genes\u00a0that\u00a0produce antibodies, the specialized proteins that help the immune system recognize and fight infections. Every other known mammal has only one such set.\u00a0The discovery opens new avenues for understanding the evolution of immunity and how animals respond to disease.<\/p>\n
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We’ve never seen anything like this in a mammal before. This completely changes our understanding of how mammalian immune systems can be organized and raises exciting new questions about why bats have been so evolutionarily successful and how they respond to viruses.”<\/p>\n
\n <\/p>\nHannah Frank, associate professor of ecology and evolutionary biology, Tulane University School of Science and Engineering and corresponding author of the study<\/p>\n
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The discovery was made in vesper bats, which includes more\u00a0than 500 species found on every continent except Antarctica. Their remarkable evolutionary success has long intrigued scientists, and this newly discovered antibody system may offer one explanation.<\/p>\n
Antibodies are Y-shaped proteins made of two heavy protein chains and two light protein chains. In humans and every other known mammal, those heavy chains are built from a single set of genes. Frank and her collaborators discovered that vesper bats instead\u00a0possess\u00a0two separate heavy-chain gene systems, giving them an entirely new way to generate antibody diversity.\u00a0<\/p>\n
While researchers have traditionally focused on bats’ innate immune systems, Frank said this study highlights the importance of looking more closely at their adaptive immune system- the part responsible for producing antibodies.<\/p>\n
“We think this discovery is an important piece of\u00a0the puzzle,” Frank said. “It doesn’t fully explain why bats are such effective viral reservoirs, but it reveals a level of immune\u00a0variety\u00a0we didn’t know existed and gives us an entirely new direction to explore.”<\/p>\n
Bats are critical\u00a0pollinators,\u00a0seed dispersers and natural pest controllers\u00a0but\u00a0also serve as natural hosts for many viruses, Frank said. Understanding how they coexist with those viruses without becoming ill may eventually help scientists better understand immune responses across species and improve strategies for preventing disease spillover.<\/p>\n
“We’ve learned an enormous amount about immunity by studying humans and laboratory mice,” Frank said. “But the natural world is far\u00a0more varied\u00a0than that. Every time we study a species that has evolved differently, we have the opportunity to discover something entirely new.”<\/p>\n
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