IL-24 is expressed by rat and human macrophages.
Recently, a number of interleukin-10 (IL-10) homologues, among them IL-24 formerly known as melanocyte differentiation factor-7 (mda-7), has been described. Since IL-10 is released by macrophages and plays an important role in the resolution of inflammatory processes, we hypothesized that IL-24 might also be expressed in cells of the monocyte/macrophage lineage. We analyzed IL-24 expression on the mRNA and protein level in stimulated rat and human macrophages. In rat alveolar macrophages and NR8383 cells, IL-24 mRNA induction was observed following stimulation with LPS and IL-4 whereas TNF-alpha failed. Intracellular IL-24 protein was detected in unstimulated and IL-4 stimulated NR8383 cells. Also human blood monocytes showed a strong up-regulation of IL-24 mRNA following preparation which was enhanced by LPS and lowered by IL-10. Furthermore, infection of human monocytes with influenza A virus A/PR/8 caused an induction of IL-24 mRNA expression. In conclusion, our data show that IL-24 expression is induced in stimulated and infected rat and human macrophages, however, more insights into the functions of IL-24 are necessary to define its physiological relevance.
Garn
Holger
H
Institute of Immunology, Philipps University, Marburg, Germany. garn@mailer.uni-marburg.de
Schmidt
Ansgar
A
Grau
Veronika
V
Stumpf
Sabine
S
Kaufmann
Andreas
A
Becker
Mike
M
Gemsa
Diethard
D
Siese
Anette
A
D000818:Animals; D016147:Genes, Tumor Suppressor; D006801:Humans; D009980:Influenza A virus / Q000378:metabolism; D007378:Interleukins / Q000096:biosynthesis / Q000235:genetics*; D016676:Macrophages, Alveolar / Q000378:metabolism*; D009000:Monocytes / Q000378:metabolism*; D009976:Orthomyxoviridae Infections / Q000378:metabolism; D051381:Rats; D000099180:Interleukin-24
D007378:Interleukins; D000099180:Interleukin-24