Induction of Apoptosis in a Macrophage Cell Line RAW 264.7 By Acemannan, a β-(1,4)-Acetylated Mannan
Abstract
Acemannan is a polydispersed β-(1,4)-linked acetylated mannan with antiviral properties. It is an immunomodulator, and studies in our laboratory have shown that it causes activation of macrophages. In the presence of IFNγ, acemannan induced apoptosis in RAW 264.7 cells. These cells exhibited chromatin condensation, DNA fragmentation, and laddering characteristic of apoptosis. The induction of apoptosis by acemannan and IFNγ does not seem to be mediated by nitric oxide, since N-nitro-l-arginine methyl ester, the nitric oxide inhibitor, had no effect. Acemannan in the presence of IFNγ also inhibited the expression of bcl-2. These results suggest that acemannan in the presence of IFNγ induces apoptosis in RAW 264.7 cells through a mechanism involving the inhibition ofbcl-2 expression.
Footnotes
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Send reprint requests to: Lalitha Ramamoorthy, Dept. of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843. E-mail: l0r7859{at}nigel.tamu.edu
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This study was supported by a grant from Carrington Laboratories, Dallas, Texas. I.R.T. is a paid consultant for Carrington Laboratories.
- Abbreviations:
- IFNγ
- interferon γ
- PBS
- phosphate-buffered saline
- SDS
- sodium dodecyl sulfate
- EGTA
- ethylene glycol bis(β-aminoethyl ether)-N,N,N′,N′-tetraacetic acid
- PAGE
- polyacrylamide gel electrophoresis
- PVDF
- polyvinylidene difluoride
- PCR
- polymerase chain reaction
- DEPC
- diethylpyrocarbonate
- G3PD
- glyceraldehyde-3-phosphate dehydrogenase
- bp
- base pair(s)
- HEPES
- 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid
- FITC
- fluorescein isothiocyanate
- l-NAME
- N-nitro-l-arginine methyl ester
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- Received June 23, 1997.
- Accepted November 7, 1997.
- The American Society for Pharmacology and Experimental Therapeutics
