CCR7 Is Mainly Expressed in Teleost Gills, Where It Defines an IgD+IgM− B Lymphocyte Subset

摘要: Chemokine receptor CCR7, the for both CCL19 and CCL21 chemokines, regulates recruitment clustering of circulating leukocytes to secondary lymphoid tissues, such as lymph nodes Peyer9s patches. Even though teleost fish do not have either these structures, we recently reported a homolog CCR7 in rainbow trout ( Oncorhynchus mykiss ). In present work, studied distribution bearing extracellular naive adult tissues by flow cytometry, observing that among different leukocyte populations, highest numbers cells with membrane mem )CCR7 were recorded gill (7.5 ± 2% + cells). comparison, head kidney, spleen, thymus, intestine, peripheral blood possessed cells. When was at early developmental stages, detected progressive increase gene expression protein levels gills throughout development. Surprisingly, majority myeloid did express CD8, IgM, nor IgT, but expressed IgD on cell surface. fact, most CCR7. Intriguingly, population coexpress IgM. Finally, when bath challenged viral hemorrhagic septicemia virus, number significantly decreased while increased kidney. These results provide evidence presence novel IgM − B lymphocyte subset expresses responds infections. Similarities subsets mammals are discussed.