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J. Exp. Med.,
Volume 188, Number 7, October 5, 1998 1255-1265
, Repressing the HIV-1
Long Terminal Repeat in Macrophages: Pulmonary
Tuberculosis Alters C/EBP Expression, Enhancing
HIV-1 Replication
By



From the * Division of Pulmonary and Critical Care Medicine and Bellevue Chest Service, New York
University Medical Center, New York 10016; the We have previously observed that HIV-1 replication is suppressed in uninflamed lung and increased during tuberculosis. In vitro THP-1 cell-derived macrophages inhibited HIV-1 replication after infection with Mycobacterium tuberculosis. Suppression of HIV-1 replication was associated with inhibition of the HIV-1 long terminal repeat (LTR) and induction of ISGF-3, a
type I interferon (IFN)-specific transcription factor. Repression of the HIV-1 LTR required
intact CCAAT/enhancer binding protein (C/EBP) sites. THP-1 cell-derived macrophages
infected with M. tuberculosis, lipopolysaccharide, or IFN-
Department of Microbiology and Infection, Institute
of Medical Science, Tokyo University, Tokyo 108, Japan; the § Department of Medicine, Sendai Kosei
Hospital, Sendai 980, Japan; and the
Public Health Research Institute, New York 10016
induced the 16-kD inhibitory
C/EBP
isoform and coincidentally repressed HIV-1 LTR transcription. C/EBP
was the
predominant C/EBP family member produced in THP-1 macrophages during HIV-1 LTR
repression. In vivo, alveolar macrophages from uninflamed lung strongly expressed inhibitory
16-kD C/EBP
, but pulmonary tuberculosis abolished inhibitory C/EBP
expression and induced a novel C/EBP DNA binding protein. Therefore, in vitro, proinflammatory stimulation
produces an IFN response inhibiting viral replication by induction of a C/EBP
transcriptional
repressor. THP-1 cell-derived macrophages stimulated with type I IFN are similar to alveolar
macrophages in the uninflamed lung in vivo. In contrast, the cellular immune response in
active pulmonary tuberculosis disrupts this innate immunity, switching C/EBP expression and
allowing high level viral replication.
;
CCAAT/enhancer binding protein
;
HIV-1 long terminal repeat;
tuberculosis;
repression
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