Quantitative uptake studies of 131I-labeled (E)-5-(2-iodovinyl)-2'-deoxyuridine in herpes simplex virus-infected cells in vitro

Abstract

We have synthesized a 131I-radiolabeled antiviral compound (E)-5-(2-iodovinyl)-2'-deoxyuridine (IVdU) and shown that this agent was selectively trapped within rabbit kidney cells, infected in vitro by thymidine kinase-positive (TK+) herpes simplex virus (HSV). The uptake of 131I-labeled IVdU was specific, as it was not concentrated within either HSV (TK-) or mock-infected cells. In certain conditions, over 40% of the radiolabel was selectively trapped within HSV (TK+)-infected cells. This was a 20- to 30-fold increase over the uptake of 131I-labeled IVdU by HSV (TK-) or mock-infected cells. The uptake of 131I-labeled IVdU varied directly with (i) the dose of the virus used to infect the rabbit kidney cells; (ii) the concentration of radiolabeled IVdU added to the system; and (iii) the time of exposure of IVdU to infected cells. The ability of this agent to be trapped within HSV (TK+)-infected cells merits further evaluation in animal models as it has potential as a noninvasive, herpes-specific diagnostic test, in particular for HSV encephalitis.

Synthesis and Cellular Uptake of 2‘-Substituted Analogues of (E)-5-(2-[125I]Iodovinyl)-2‘-deoxyuridine in Tumor Cells Transduced with the Herpes Simplex Type-1 Thymidine Kinase Gene. Evaluation as Probes for Monitoring Gene Therapy

“…At 8 h after exposure, 66% of the radioactivity (25 pmol/10 5 cells) was intracellularly trapped. The kinetic profile of the uptake process is qualitatively similar to that observed previously with [ 131 I]IVDU in TK + HSV-1-infected rabbit kidney cells b).…”

“…The kinetic profile of the uptake process is qualitatively similar to that observed previously with [ 131 I]IVDU in TK + HSV-1-infected rabbit kidney cells. 28 [ 125 I]IVFRU also accumulated rapidly in KBALB-STK cells, with increasing cellular radioactivity over time (see Figure 1b). However, the presence of a 2′-fluorine substituent in the ribofuranosyl configuration appears to affect cellular nucleoside uptake, since there was substantially lower cellular uptake of [ 125 I]IVFRU relative to [ 125 I]- IVDU.…”

Radiolabeled antiviral drugs and antibodies as virus-specific imaging probes

“…Beginning in the early 1980s, investigators succeeded in showing that, even though the blood-brain barrier normally restricts the entry of deoxythymidine analogues into the central nervous system, the increased permeability associated with viral infection permitted the entry of a sufficient amount of probe to label infected cells. In a series of studies, rats were infected intraocularly with HSV-1, and after an appropriate interval were injected intravenously with a small dose of 14 C-labeled 2 -fluoro-5methyl-1-␤-d-arabinosyluracil (FMAU) or with 131 I-or 125 I-labeled E-5-(2-iodovinyl)-2 -deoxyuridine (IVDU) (Gill et al, 1984;Klapper et al, 1988;Price et al, 1983;Saito et al, 1984;Cleator et al, 1988). Foci of encephalitis were identified either by killing animals and performing autoradiography on brain slices, or by imaging live animals using a gamma camera.…”

Effect of acyclovir on the uptake of 131 I‐labelled 1‐(2′fluoro‐2′‐deoxy‐βD‐D‐arabinofuranosyl)‐5‐lodouracil in herpes infected cells

“…As this procedure is invasive, its use is often delayed. The demonstration of the selective uptake of labelled nucleoside analogues in HSV infected cells in vitro justifies their evaluation for a diagnostic brain scan that would be sensitive early in the disease [Gill et al, 1984;Price et al 19831. The…”