Ascorbate effect on cytokine stimulation of HIV production.
Nutrition 1995 Sep-Oct;11(5 Suppl):684-7 (ISSN: 0899-9007)
Harakeh S; Jariwalla RJ Virology and Immunodeficiency Research
Program, Linus Pauling Institute of Science and Medicine, Palo Alto, California
We have recently shown that ascorbic acid (AA) suppresses the production
of HIV in a latently infected T-lymphocytic cell line (ACH-2) following
stimulation with the tumor promoter, PMA. To evaluate the effect of ascorbic
acid on virus activation following treatment with inflammatory cytokine,
we tested tumor necrosis factor alpha (TNF-alpha) whose levels are elevated
in patients with HIV/AIDS. ACH-2 cultures, pretreated with various nontoxic
concentrations of ascorbate or AZT were stimulated for 2 h with TNF-alpha,
and incubated further with fresh supplements of ascorbate or AZT. At 24
to 48 h post-treatment, the Reverse Transcriptase (RT) activity released
into culture supernatant was determined. Results showed that TNF-alpha
alone caused approximately 13- to 16-fold stimulation in the level of
extracellular RT. Pretreatment with ascorbic acid at 200 micrograms/ml
caused a little more than about 2- to 4-fold reduction in extracellular
RT levels. Most remarkably, exposure to 300 micrograms/ml ascorbate resulted
in approximately 5- to 10-fold lowering of the extra-cellular RT titer.
In contrast, no significant suppression in extracellular RT levels was
seen with concentrations of AZT in the range of 1-5 micrograms/ml.