Anti-HIV / HCV activity of cyanobacterial phycobiliproteins by a new standardized method using bacteriophage surrogates

Abstract

The control of the viral infections requires efficient, rapid and safe testing procedures. We tested the efficiency of a quick and reliable alternative assay to the standard plaque assay (PA) in the detection of viral inhibition. Using MS-2 and ΦX-174 phages, the developed assay was used to evaluate the potential of cyanobacterial phycobiliproteins (PBS) as natural antiviral bioactive molecules against HIV and HCV. The antiviral activity was examined by mixing the phage with crude aqueous extracts in a 1:1 (v/v) ratio for 1hr at 4oC. The viral titer of MS-2 and ΦX-174 was reduced by 0.92 LR and 1.19 LR, respectively. In the case of the crude PBS extract of Spirulina platensis, similar result trends were obtained by virion titration which indicated that a strong correlation between the two assays was verified (≥90 %). The morphological characteristics of both phages were severely affected when treated with the extract, whereas the characteristic features of their hosts seem unaffected. The PBS was found to affect the adsorption of the phages on their bacterial hosts and consequently viral reproduction. In conclusion, MS-2 and ΦX-174 can be used in drug evaluation by the well standardized method developed in this study.