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Three different IgD cell populations in channel catfish, Ictaulurus punctatus
Author(s) -
Edholm EvaStina,
Stafford James,
Sahoo Manoranjan,
Bengten Eva,
Miller Norman,
Wilson Melanie
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.863.4
Subject(s) - immunoglobulin d , catfish , biology , antibody , microbiology and biotechnology , population , immunology , b cell , immunoglobulin e , medicine , fish <actinopterygii> , environmental health , fishery
IgM and IgD are currently the only immunoglobulin (Ig) molecules identified in catfish. While catfish IgM resembles mammalian IgM, catfish IgD is quite different. It is a chimeric molecule consisting of a rearranged VDJ region spliced to the Cμ1 domain, followed by seven Cδ domains and either a transmembrane or secreted tail. To study catfish IgD function, monoclonal anti‐Igδ antibodies were generated. Flow cytometry and cell separation techniques demonstrate the presence of three IgD + populations in peripheral blood leukocytes (PBL). Two are B lymphocyte‐like populations with one expressing messages for the membrane forms of Igμ and Igδ (IgM + /IgD), and the other only expressing the membrane form of Igδ (IgM − /IgD + ). Moreover, PCR protocols amplify appropriate rearranged Ig messages from both populations indicating that they contain functional B cells. In contrast to the situation in mammals where IgM − /IgD + B cells are rare, IgM − /IgD + cells can represent as much as 60% of the total PBL in some catfish. The third population consists of IgM − /IgD + granular‐like cells of unknown origin that do not express Igδ message, but appear to be armed with exogenous IgD via an IgD‐binding receptor. At the present, the function of the granulocytes is unknown, however they degranulate in response to cross‐linking of the surface bound IgD. Supported by NIH grant R01 AI19530; USDA grant 2005‐01812 .