Interferon-alpha and interferon-beta induce Ia expression in limited protein synthesis condition.
We investigated the regulatory effect of interferons (IFNs) on macrophage (m phi) Ia antigen expression. Unlike type II IFN (IFN-gamma), type I IFNs (IFN-alpha and IFN-beta) were incapable of inducing the accumulation of Ia mRNA. However, when cultured with type I IFN plus cycloheximide (CHX), M phi accumulated significant amounts of Ia-specific mRNA, which was translated into Ia molecules expressed on the cell surface after the removal of CHX. Significant enhancement of Ia mRNA accumulation and the Ia expression were observed also in M phi stimulated with IFN-gamma plus CHX. Type I IFNs suppressed IFN-gamma-dependent Ia expression through the inhibition of Ia mRNA accumulation, but such suppression was not directed to the post-transcriptional step in M phi that had accumulated Ia mRNA in response to stimulation by type I or type II IFN plus CHX. These results seem to indicate that type I IFNs can induce Ia mRNA accumulation but that they also induce some inhibitory protein, the synthesis of which precedes it and is dominant, so that the Ia expression is masked.
Kitaura
M
M
Department of Zoology, Faculty of Science, Kyoto University, Japan.
Inaba
K
K
Inaba
M
M
Ogata
H
H
Watanabe
Y
Y
Shimizu
S
S
Ikehara
S
S
Muramatsu
S
S
D000818:Animals; D015152:Blotting, Northern; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015395:Histocompatibility Antigens Class I / Q000096:biosynthesis*; D007370:Interferon Type I / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology; D014176:Protein Biosynthesis / Q000187:drug effects; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology*; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D011994:Recombinant Proteins
D015395:Histocompatibility Antigens Class I; D007370:Interferon Type I; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D011994:Recombinant Proteins; D007371:Interferon-gamma; D003513:Cycloheximide