Human B-cell interleukin-10: B-cell lines derived from patients with acquired immunodeficiency syndrome and Burkitt's lymphoma constitutively secrete large quantities of interleukin-10.
A recent addition to the lymphokine network is human IL-10 (hIL-10). This novel lymphokine has striking homology to BCRF1 protein, the product of a previously uncharacterized open-reading frame in the Epstein-Barr virus (EBV) genome. To date, IL-10 expression has been described in several T clones induced with anti-CD3 and phorbol myristate acetate (PMA), in monocytes stimulated with lipopolysaccharide (LPS), and in murine B-cell lymphomas. We sought to determine whether human B cells express hIL-10 and, if so, its relationship to EBV and to other B-cell lymphokines. We studied 21 EBV-positive B-cell lines derived from patients with acquired immunodeficiency syndrome (AIDS) and Burkitt's lymphoma (n = 6), American Burkitt's (n = 3), African Burkitt's (n = 5), and normal lymphoblastoid cell lines (n = 7), in comparison with seven EBV-negative cell lines. All cell lines were activated with the tumor promoters PMA and teleocidin and were studied by Northern blot analysis, reverse transcription-polymerase chain reaction (RT-PCR), and enzyme-linked immunoadsorbent assay (ELISA). We demonstrated that EBV-positive cell lines derived from patients with American Burkitt's lymphoma, and especially those from patients with AIDS, constitutively express large quantities of hIL-10 by Northern blot analysis and ELISA (range, 3,101 to 25,915 pg/mL), and that both teleocidin and PMA induce hIL-10 in these cell lines. In contrast, six of seven EBV-negative cell lines did not express hIL-10 even by RT-PCR, and hIL-10 was not triggered by PMA or teleocidin. To assure that the 350 bp amplified by PCR was hIL-10 and not BCRF1, we used PCR primers, which do not amplify a fragment from plasmid templates containing BCRF1. Cloning and sequencing of the 350 bp product also demonstrated that B-cell IL-10 is identical to hIL-10 from the T-cell clone B21. Correlation of hIL-10 with other B-cell lymphokines secreted by these B-cell lines demonstrated that hIL-10 secretor cell lines also constitutively secrete or can be induced to secrete IL-6, although to a much lesser amount. Since both lymphokines influence B-cell growth and differentiation, we suggest that hIL-10 may contribute to the polyclonal B-cell activation and hyperglobulinemia seen in AIDS patients. Finally, several reports support the hypothesis that EBV is an important cofactor in the development of human immunodeficiency virus type 1 (HIV-1)-related B-cell lymphomas. Detection of large quantities of hIL-10 in B-cell lines derived from AIDS patients, the close association between EBV and hIL-10 shown in this report, and the ability of BCRF1 to capture hIL-10 activities, make hIL-10/BCRF1 an attractive candidate as a factor causing B-cell growth and immortalization in patients with AIDS and B-cell lymphomas.
Benjamin
D
D
Division of Hematology and Oncology, Arthur G. James Cancer Hospital and Research Institute, Ohio State University, Columbus 43210-1228.
Knobloch
T J
TJ
Dayton
M A
MA
D000163:Acquired Immunodeficiency Syndrome / Q000378:metabolism*; D001402:B-Lymphocytes / Q000378:metabolism* / Q000382:microbiology; D001483:Base Sequence; D002051:Burkitt Lymphoma / Q000378:metabolism*; D002460:Cell Line; D003001:Cloning, Molecular; D004854:Herpesvirus 4, Human; D006801:Humans; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism*; D015850:Interleukin-6 / Q000378:metabolism; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis
D015850:Interleukin-6; D012333:RNA, Messenger; D016753:Interleukin-10