New research shows that fruit bats produce significantly less of these reinforcements when they are exposed to viruses, compared with rodents; however, surprisingly a fruit-only diet is enriched in cytokines and can enhance their immune response. This discovery questions the common paradigm of bats and zoonotic viruses and allows for strategies mitigating future pandemics.
Bats’ Unique Immune Responses
For many viruses with pandemic potential, bats are the natural reservoir, yet bats rarely suffer from pandemic viral infections. This has not gone unnoticed, with a group of scientists launching a bat immunology project to uncover ways that the bat immune system can drive spelofeverse (virus spillovers from bats into humans).
The results of a new study, published in PLOS Biology, reveal that fruit bats make more varied antibodies against viruses than mice do—but their overall antibody response is also smaller. This might seem paradoxical, given that a robust antibody response is frequently associated with the best virus neutralization and elimination. The authors propose the distinct immune signature may represent an evolutionary in spotlighting bat ability to easily carry these deadly pathogens.
Diet Can Significantly Influence Bat Immunity
Diet and how it shapes the bats’ antibody response to viruses Among the more striking discoveries of their study is the apparently profound effect of diet. However, bats that only ate fruit had an almost 50-fold increase in the proteins used to create antibodies compared to those on a protein-supplemented diet.
In the case of bats, this could mean that their immune system is especially attuned to shifts in dietary protein intake. The scientists suggest that because the fruit-only diet might have the optimal amounts of nutrients and antioxidants necessary for a more vigorous antibody response, it could be part of what makes these bats so successful.
These findings may be relevant given that ecological disturbances associated with nutrient-related food shortages are likely to affect the ability of bats to control viral infections. It also raises questions around the part diet may play in enabling such zoonotic viruses to spill over from bats into human populations.
Conclusion
This study’s results suggest bats are likely not the origin of zoonotic viruses, as previously thought. This broader antibody response in the frugivorous bats could be developed into model studies to explore the role of diet on virus spillover events by further evaluating their effect on cross-protective immunity. Such insights could have applications in reducing the risk of future pandemics by illuminating the intricate dance that goes on between bats’ immune systems, what they eat, and how deadly viruses are passed on among them.
