Page, D.M., Wittamer, V., Bertrand, J.Y., Lewis, K.L., Pratt, D.N., Delgado, N., Schale, S.E., McGue, C., Jacobsen, B.H., Doty, A., Pao, Y., Yang, H., Chi, N.C., Magor, B.G., and Traver, D. (2013) An evolutionarily conserved program of B cell development and activation in zebrafish. Blood. 122(8):e1-e11.
Teleost fish are among the most ancient vertebrates possessing an adaptive immune system with B and T lymphocytes that produce
memory responses to pathogens. Most bony fish, however, have only two types of B lymphocytes, in contrast to the four types
available to mammals. To better understand the evolution of adaptive immunity, we generated transgenic zebrafish in which
the major IgM+ B cell subset expresses GFP (IgM1:eGFP). We discovered that the earliest IgM+ B cells appear between the dorsal aorta and posterior cardinal vein and also in the kidney around 20 days post-fertilization.
We also examined B cell ontogeny in adult IgM1:eGFP; rag2:DsRed animals, where we defined pro-, pre-, and immature/mature B cells in the adult kidney. Sites of B cell development that
shift between the embryo and adult have previously been described in birds and mammals. Our results suggest that this developmental
shift occurs in all jawed vertebrates. Finally, we used IgM1:eGFP and cd45DsRed; blimp1:eGFP zebrafish to characterize plasma B cells and investigate B cell function. The IgM1:eGFP reporter fish are the first non-mammalian B cell reporter animals to be described. They will be important for further investigation
of immune cell evolution and development and host-pathogen interactions in zebrafish.