Isolation and Preliminary Characterization of Chalcone Ro 09-0410-Resistant Human Rhinovirus Type 2

We have isolated a human rhinovirus type-2 (HRV-2) mutant that is resistant to the antiviral agent chalcone Ro 09-0410 (4′-ethoxy-2′-hydroxy-4, 6′-dimethoxychalcone). This Ro 09-0410-resistant HRV-2 mutant (SR2-0410) exhibited altered biological properties when compared with the parental wild-type (wt) HRV-2. It was unstable when exposed to acid and heat in the presence of the drug, was incapable of producing plaques and produced an early cytopathic effect (CPE) at high temperatures (35°C and 37°C). Furthermore, compared with the parental wild-type, it showed a reduced ability to be neutralized by an anti-HRV-2 polyclonal serum and monoclonal antibodies. This SR2-0410 mutant demonstrated cross-resistance to other synthetic anti-rhinovirus compounds, which are also thought to bind to the viral capsid protein (VPI), such as 4′,6-dichloroflavan, 3-methoxy-6-[4-(3-methylphenyl)-I-piperazinyl] pyridazine (R 61837) and WIN 51711 (5-[7-[4-(4,5-dihydro-2-oxazolyl) phenoxyl] heptyl]-3-methyl-isoxazole). Furthermore, it was also resistant to various antiviral combinations synergistic against HRV-2. However, it was still sensitive to enviroxime [2-amino-I-(isopropyl sulphonyl)-6-benzimidazole phenyl ketone oxime], which has a different mode of action and is thought to interfere with viral RNA synthesis.

Jordanian population data on the PCR-based loci: LDLR, GYPA, HBGG, D7S8 and GC

Genotype and allele frequency distributions for PM polymerase chain reaction (PCR)-based genetic markers were determined in a Jordanian sample population. Results were obtained using the AmpliType PM PCR Amplification and typing kit. All loci were in agreement with the Hardy-Weinberg equilibrium expectations. The predominant alleles for LDLR, GYPA, HBGG, D7S8 and GC loci were B, A, B, A and C respectively. No statistically significant variation was detected in allele frequencies of these loci in Jordanians compared to that in Israeli Arab, U.S Caucasian and Japanese populations. Data presented here can be used to estimate the frequency of a specific DNA profile in the Jordanian population for forensic analyses and paternity testing.

Pathogenicity for humans of human rhinovirus type 2 mutants resistant to or dependent on chalcone Ro 09-0410

Mutants of human rhinovirus type 2 (HRV-2) resistant to and dependent on the antirhinoviral compound chalcone Ro 09-0410 were selected in cell culture under clean laboratory conditions. A total of 42 volunteers were challenged with either the drug-resistant mutant [SR2-410(r)] (15 volunteers), the drug-dependent mutant [SR2-410(d)] (15 volunteers), or a wild-type HRV-2 which had a similar passage level in vitro as the mutants but without the drug (12 volunteers). Of volunteers challenged with the wild-type HRV-2, 33, 67, and 82% developed cold symptoms, shed virus, and showed serological evidence of infection, respectively. In contrast, only 13, 27, and 23% of volunteers challenged with the drug-resistant mutant developed colds, shed virus, and showed serological evidence of infection, respectively. None of the volunteers challenged with the drug-dependent virus became infected or had symptoms of colds. These results demonstrate that a drug-resistant rhinovirus was capable of infecting humans and producing disease, although its infectivity was reduced when compared with that of the wild type. In contrast, a drug-dependent virus had lost its ability to infect humans.