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Constitutive expression of specific interferon isotypes in peripheral blood leukocytes from normal individuals and in promonocytic U937 cells
Author(s) -
Lallemand Christophe,
Lebon Pierre,
Rizza Paola,
Blanchard Brigitte,
Tovey Michael G.
Publication year - 1996
Publication title -
journal of leukocyte biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.819
H-Index - 191
eISSN - 1938-3673
pISSN - 0741-5400
DOI - 10.1002/jlb.60.1.137
Subject(s) - biology , interferon , microbiology and biotechnology , u937 cell , peripheral blood mononuclear cell , endogeny , gene expression , cell culture , gene , immunology , in vitro , biochemistry , genetics
Constitutive expression of IFN‐α5 and IFN‐β was detected in different lymphoid cells including peripheral blood mononuclear cells from normal individuals following amplification of IFN mRNA by reverse transcriptase–polymerase chain reaction and direct sequencing of the amplified product. The activated form of the interferon‐induced transcription factor complex ISGF3 was also dectected in nuclear extracts from uninduced cells. Culture supernatants from uninduced U937 cells were also found to activate an ISRE cloned upstream of the luciferase reporter gene, indicating the presence of endogenous IFN activity equivalent to approximately 0.3 to 0.5 IU/mL. This endogenous IFN was also shown to play a role in mamtaining the basal level of expression of the major histocompatibility class I genes in lymphoid cells. These results suggest that IFN‐α5 and IFN‐β are produced at low levels in normal tissues and play an important role in the regulation of cell function and in the maintenance of homeostasis.