The finding, which appears in the online version of Nature Immunology and will be featured on the cover of the October issue, represents a sizeable evolutionary step for the mammalian immune system and offers a potential new strategy for developing much-needed fish vaccines.
"When examining fish B cells we see them actively attacking and eating foreign bodies, which is a behavior that, according to the current dogma, just shouldn't happen in B cells," said J. Oriol Sunyer, a professor in Penn Vet's Department of Pathobiology. "I believe it is evidence for a very real connection between the most primitive forms of immunological defense, which has survived in fish, and the more advanced, adaptive immune response seen in humans and other mammals."
About 400 million years ago, the earliest ancestors of modern fish split off of the evolutionary pathway that became the earliest ancestors of modern mammals. In modern mammals, the B cell is a highly adapted part of the immune system chiefly responsible for, among other things, the creation of antibodies that tag foreign particles and microbes for destruction. Mammals have phagocytic cells, but they are a specialized few cells identified apart from the complex interactions that drive other white blood cells.
Sunyer and his colleagues discovered this previously unsuspected B cell activity while examinin
Source:University of Pennsylvania