Characterization of the inhibition of interleukin 2 mRNA accumulation by 12-O-tetradecanoylphorbol-13-acetate in primary lymphocytes.
We found previously that bovine lymph node cells (LNC) incubated with 12-O-tetradecanoylphorbol-13-acetate (TPA) for 18 h proliferate only to a limited degree on subsequent stimulation with concanavalin A (Con A), or with the comitogenic combination of Con A plus TPA. The lack of proliferation was traced to a lack of secretion of interleukin 2 (IL-2). Lack of secretion was paralleled by a decrease in IL-2 mRNA levels. In this study we further characterized how TPA pretreatment affected IL-2 mRNA production. We found that TPA depressed IL-2 mRNA accumulation in a dose-dependent manner after at least 10 h of pretreatment. In contrast, pretreatment from 4 to 6 h augmented IL-2 mRNA accumulation. Furthermore, LNC stimulated with ionomycin plus TPA were less susceptible to inhibition by pretreatment with TPA, most likely because this mitogenic combination caused a much greater amount of IL-2 mRNA than did Con A or Con A plus TPA. Finally, a protein synthesis inhibitor, cycloheximide, partially counteracted the negative effects of TPA on IL-2 mRNA accumulation and on proliferation. These results suggest that TPA, probably acting through protein kinase C, initially augments the production of IL-2 mRNA but subsequently induces mechanisms to decrease the level of mRNA.
Garlisi
C G
CG
Department of Molecular and Cell Biology, Pennsylvania State University, University Park 16802.
Mastro
A M
AM
D000818:Animals; D015152:Blotting, Northern; D002417:Cattle; D002455:Cell Division / Q000187:drug effects; D003208:Concanavalin A / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D007371:Interferon-gamma / Q000096:biosynthesis / Q000235:genetics; D007376:Interleukin-2 / Q000096:biosynthesis / Q000235:genetics*; D015759:Ionomycin / Q000494:pharmacology; D008198:Lymph Nodes / Q000166:cytology; D008213:Lymphocyte Activation; D008214:Lymphocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*
D007376:Interleukin-2; D012333:RNA, Messenger; D003208:Concanavalin A; D015759:Ionomycin; D007371:Interferon-gamma; D003513:Cycloheximide; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate