IL-12 expression in AIDS-related lymphoma B cell lines.
IL-12 is a 70-kDa heterodimer formed by the 40-kDa heavy chain (p40) and the 35-kDa light chain (p35). Twenty-five Burkitt's lymphoma cell lines (CL) and seven normal lymphoblastoid B CL were studied. The Burkitt's CL included AIDS-associated B CL (AABCL) (7 EBV+/2 EBV-) and non-AABCL (8 EBV+/8 EBV-). Reverse transcription-PCR detected p40 in EBV+ AABCL (7 of 7), EBV+ non-AABCL (3 of 8), and normal lymphoblastoid B CL (6 of 6) but not in EBV- CL (0 of 10). p35 mRNA was detected in 30 of 30 CL. Constitutive secretion of p40 was found in 7 of 7 EBV+ AABCL (range, 341-18,086 pg/ml) and p70 in 3 of 7 EBV+ AABCL (range, 25-197 pg/ml), but in only 1 of 8 EBV+ non-AABCL and 0 of 7 normal lymphoblastoid CL. PMA stimulated p40 secretion in 7 of 7 EBV+ AABCL and p70 secretion in 5 of 7 EBV+ AABCL. PMA also triggered p40 and p70 secretion in 2 EBV+ non-AABCL and in 3 of 7 normal lymphoblastoid CL. No IL-12 secretion was detected in 10 EBV- CL, including EBV- AABCL. The CL produced IL-10, a known inhibitor of IL-12, but anti-IL-10 Abs did not neutralize IL-12. Similarly, neutralizing anti-IFN gamma Abs or IFN gamma did not affect B cell IL-12. For IL-12R studies, reverse transcription-PCR and 125I-IL-12 binding assays were performed. Although all CL tested showed mRNA accumulation for one of the IL-12R components, IL-12 binding sites were detected in only 1 of 30 CL. Our data suggest that: 1) AABCL constitutively secrete large amounts of IL-12, contrasting with low IL-12 production by HIV-1 infected PBMC; 2) lack of IL-12 expression in EBV- AABCL suggests that in vivo exposure of B cells to HIV-1 only does not induce IL-12 secretion and that both HIV-1 and EBV are required; 3) the autocrine-negative effect of IL-10 on IL-12 in monocytes and the enhancing effect of IFN gamma on IL-12 secretion do not apply to B cells derived from AIDS patients.
Benjamin
D
D
Division of Hematology and Oncology, Arthur G. James Cancer Hospital and Research Institute, Columbus, OH 43210, USA.
Sharma
V
V
Kubin
M
M
Klein
J L
JL
Sartori
A
A
Holliday
J
J
Trinchieri
G
G
D000163:Acquired Immunodeficiency Syndrome / Q000150:complications / Q000276:immunology*; D001483:Base Sequence; D002051:Burkitt Lymphoma / Q000378:metabolism; D003001:Cloning, Molecular; D017931:DNA Primers / Q000737:chemistry; D015870:Gene Expression; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D016753:Interleukin-10 / Q000378:metabolism; D018664:Interleukin-12 / Q000235:genetics / Q000378:metabolism*; D016483:Lymphoma, AIDS-Related / Q000150:complications / Q000378:metabolism*; D016393:Lymphoma, B-Cell / Q000150:complications / Q000378:metabolism*; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000235:genetics; D018123:Receptors, Interleukin / Q000235:genetics / Q000378:metabolism; D053707:Receptors, Interleukin-12; D014407:Tumor Cells, Cultured
D017931:DNA Primers; D012333:RNA, Messenger; D018123:Receptors, Interleukin; D053707:Receptors, Interleukin-12; D016753:Interleukin-10; D018664:Interleukin-12; D007371:Interferon-gamma