Plaque Assay of the Effects of Cytosine Arabinoside and 5-lodo-2′-deoxyuridine on the Synthesis of H-1 Virus Particles

Abstract

H-1 VIRUS, one of a new group of small agents that produce a specific deformity when injected into newborn hamsters^1–4, is presumed to contain DNA⁵, It has been suggested recently, on the basis of its staining reaction with acridine orange, that the nucleic acid of X14 (ref, 4), another member of the H-viruses, is single-stranded DNA (ref, 6). No other animal virus is known to contain DNA of this kind, with the possible exception of the defective adenosatellite viruses⁷, and the H-viruses would appear to merit particular attention. Until now, biochemical experiments on any of the H-viruses have been hampered by the lack of a plaque assay system. This communication reports the development of a plaque assay for H-1 and the results of an investigation of the effects of the DNA antagonists 5-iodo-2′-deoxyuridine (IUDR) and cytosine arabinoside (1-β-D-arabinofuranosylcytosine) (ara C) on the synthesis of H-1. In the presence of ara C, infected cells failed to produce either viral haemagglutination activity (HA) or infectivity, while IUDR did not prevent HA but markedly reduced infective virus formation.