Scientists have identified an extraordinary enzyme belonging to the terpene synthase family that produces a framework of oxygen atoms essential for some of the most recognized naked mole-rat antibodies. It also calls into question the distinct immune system of these incredible rodents and their adaptations over evolutionary history.
The Vanishing Defenders
These naked mole-rats can live to be 40, which is incredibly long for a rodent. But a new study has revealed a chink in their armor. A study has found that these subterranean creatures are deficient in more than a third of their CD1 genes, which help the body fight off infections.
The CD1 proteins act as a kind of flag: they alert the immune system T-cells to bacteria, viruses and other pathogens that would otherwise go unnoticed. This then allows the T-cells to recognise and kill off the infected cells in question thus at the same time stop further spread of disease. It was news to researchers that the naked mole-rat defied nature, and unlike almost all other mammals, had lost a major component of its immune system.
Unconventional Immunity
We suspected that the absence of the CD1 proteins in naked mole rats might be a clue to an extraordinary adaptation in their immune system. These animals contract an infection that is lethal to mostly all other mammals, as they lack natural killer T-cells and their activity depends on functional CD1 genes. This implies that naked mole-rats have evolved other, presumably CD1-independent strategies to tackle infections and diseases.
Based on the findings, other immune molecules — including myeloid cells as well as T-lymphocytes with a specific function — may have taken the place of CD1 proteins and natural killer T-cells. This evolutionary re-tooling of the naked mole-rat’s immune system showcases new colours within the impressive palette of possibilities of these strange rodents.
The implications of this finding are broader than for the naked mole-rat alone. Given the popularity of these animals in preclinical drug testing, lacking CD1 proteins could lead to serious confusion about what physiological functions are actually appropriate. Researchers will have to account for those quirks when translating findings in the naked mole-rat’s immune response to that of other mammals.
Conclusion
The finding that naked mole-rats have jettisoned a major class of infection-fighting proteins provides an intriguing window into the evolutionary past and adaptations of these extraordinary rodents. The specifics of what this means for their inbred immune system and its function(s) beyond antioxidation has yet to be seen, but we know that these animals have some remarkable and unconventional ways to make a home down below. As more work is done on naked mole-rat and its biology, even more surprises are likely in store for us — and who knows what medical treatments and therapies we could develop from those surprises.
