ILA, the human 4-1BB homologue, is inducible in lymphoid and other cell lineages.
We recently identified a gene that is induced by lymphocyte activation (ILA). The sequence of the full-length 1.4-kb cDNA characterized ILA as a new member of the nerve growth factor/tumor necrosis factor (NGF/TNF) receptor family and the human homologue of the murine T-cell-specific receptor 4-1BB. The present study demonstrates ILA mRNA isoforms at 4.4, 4.0, and 1.8 kb in poly-A+ RNA from activated, but not from resting human peripheral blood T lymphocytes. A reverse transcriptase-polymerase chain reaction (RT-PCR) assay was used to study tissue distribution and regulation of ILA expression. The gene was induced in T lymphocytes by phytohemagglutinin (PHA), phorbol myristate acetate (PMA), and antibody to CD3, in B lymphocytes by PMA and antibodies to cell surface Ig, and in blood monocytes by interleukin-1 beta (IL-1 beta), lipopolysaccharide (LPS), and PMA. In T lymphocytes, ILA mRNA was detectable 1.5 hours after stimulation, reached maximal levels at 8 hours, and declined to background levels by 48 hours. Induction of ILA mRNA required protein synthesis and was primarily due to increased transcription. Actinomycin D reduced ILA mRNA levels in activated lymphocytes 50% within 30 minutes, demonstrating a relatively short half-life of this mRNA. Analysis of nonlymphoid cells showed that ILA mRNA was not detectable in resting cells. However, in contrast to the lymphoid-specific expression of the murine 4-1BB gene, ILA was detected in nonlymphoid cells, including epithelial and hepatoma cells after stimulation with IL-1 beta. ILA was not detectable in several brain derived cell lines. The ILA cDNA encodes a 30-kD protein as demonstrated by in vitro translation, and this protein is immunoprecipitated by antisera that were raised against ILA peptides or a glutathione-S-transferase fusion protein. Flow cytometry showed expression of ILA protein on a subset of activated T or B lymphocytes. In conclusion, activation-dependent expression of ILA is found not only in T lymphocytes, but also in B lymphocytes, monocytes, and diverse nonlymphoid cell types.
Sam and Rose Stein Institute for Research on Aging, San Diego, La Jolla, CA.
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Schwarz
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Valbracht
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Tuckwell
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von Kempis
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M
Lotz
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD; D001402:B-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D001483:Base Sequence; D002460:Cell Line; D003513:Cycloheximide / Q000494:pharmacology; D017931:DNA Primers; D005786:Gene Expression Regulation; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D007700:Kinetics; D008070:Lipopolysaccharides / Q000494:pharmacology; D051379:Mice; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000096:biosynthesis; D018121:Receptors, Cytokine / Q000096:biosynthesis* / Q000737:chemistry; D017475:Receptors, Nerve Growth Factor / Q000737:chemistry; D018124:Receptors, Tumor Necrosis Factor / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D013601:T-Lymphocytes / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9
D015703:Antigens, CD; D017931:DNA Primers; C084945:ILA receptor; D007375:Interleukin-1; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D018121:Receptors, Cytokine; D017475:Receptors, Nerve Growth Factor; D018124:Receptors, Tumor Necrosis Factor; C505714:TNFRSF9 protein, human; C505715:Tnfrsf9 protein, mouse; D053261:Tumor Necrosis Factor Receptor Superfamily, Member 9; D003513:Cycloheximide; D013755:Tetradecanoylphorbol Acetate