Novel Anti-viral Peptide Against Avian Influenza Virus H9N2 - Recent Advances in Microbiology - page 41

Figure 1. Binding ability of all four recombinant phages to AIV H9N2. Briefly, viruses were coated
in the microwell plate at two different concentrations (5 μg and 10 μg/ml; 200 μl) and were detected
by two different concentrations of recombinant phage molecules (1,012 pfu/ml and 1,011 pfu/ml).
Dotted bars represent the 5 μg of target whereas solid bars represent 10 μg of target. All the four types
of recombinant phage particles could able to detect the target AIV. Wild type phage M13 was used
as control (Data not shown to avoid complexity of the graph). A--ILGDKVG (5%), B--NDFRSKT
(47%), C--LPYAAKH (23%), D--QHSTKWF (5%), Blue Square--1,011 pfu/ml, Gray Square--012
pfu/ml.
Antiviral Activity of Peptides and Fusion Phages In Vitro
The fusion phage FP-P1 and the cyclic as well as linear peptides were evaluated for
its ability to inhibit viral-induced cell death using a cytotoxicity assay as explained
by Jones et al. (2005). Briefly, MDCK cells were mock inoculated (medium alone) or
inoculated with different concentrations of phage or peptide treated AIV virus (MOI of
0.05 pfu/cell), and cell viability was evaluated at 48 hpi. If the FP-P1 phages were able
to inactivate the AIV, then the AIV might not be able to induce the cell death and so the
viability will increase. Interestingly, pre-treatment with increasing concentration of FP-
P1 as well as the peptides increased the cell viability in dose dependent manner. More
than 100% increase in viability was observed with the fusion phage and peptide treat-
ment. In contrast, treatment with the wild type phage and control peptides did not show
any significant increase in viability (Figures 2 and 3). This observation demonstrates
that the fusion phage FP-P1 as well as the peptides (both in linear as well as cyclic
form) was capable of inactivating the virus or inhibiting the viral replication in vitro .
Figure 2. Antiviral activity of peptides in vitro . The MDCK cells were inoculated with untreated
AIV H9N2 or treated with increasing concentration of linear, cyclic, and control peptides and the
cell viability was determined by MTT assay. Results shown are the mean of three trials +/- SD. (*,
statistical significance (P < 0.05).