In vitro inhibition of human cytomegalovirus replication in human foreskin fibroblasts and endothelial cells by ascorbic acid 2-phosphate.

Antiviral activity of L-ascorbic acid-2-phosphate (ASC-2P), a long-acting derivative of L-ascorbic acid, against several human cytomegalovirus (CMV) strains was examined in cultures of human foreskin fibroblasts (HFF) and endothelial cells (EC). ASC-2P at concentrations ranging from 0.2 to 2 mM had no effect on the number of cells expressing 72 kDa CMV immediate early antigen (IEA) while it inhibited expression of 68 kDa late antigen (LA) in infected cultures of both cell types (30% and 55% reduction for EC and HFF, respectively). In HFF cells, virus yield was reduced up to 4-fold, when ASC-2P was added after CMV infection. Antiviral effects were significantly increased in cultures pretreated with ASC-2P. In HFF and EC pretreated for three subcultures (18 days) with 0.2 mM ASC-2P, a significant reduction of cells expressing IEA (75% and 80% reduction in EC and HFF, respectively) and LA (92% and 90% reduction for EC and HFF, respectively) was observed. Pretreatment for three subcultures with ASC-2P inhibited virus yield 50- to 100-fold in EC and 100- to 1000-fold in HFF. The continuous presence of ASC-2P was not required for its antiviral activity. A significantly higher reduction of virus replication with ganciclovir and foscarnet was obtained in ASC-2P pretreated cells than in untreated controls. The results showed that ASC-2P provides L-ascorbic acid with long-lasting antiviral activity against CMV. ASC-2P may be of benefit for the adjunctive treatment of CMV infection.