Interferon alfacon1 is an inhibitor of SARS-corona virus in cell-based models

Abstract

Preliminary data examining interferon alfacon1 treatment of SARS-CoV (severe acute respiratory syndrome-corona virus)-infected patients suggests this therapy is well tolerated and of therapeutic benefit. We report herein that interferon alfacon1, has potent in vitro antiviral activity against SARS-CoV. In a cytopathic effect protection (CPE) assay, interferon alfacon1 inhibited the generation of CPE in a dose-dependent manner with an IC50 of 0.001 microg/ml, a clinically achievable level. Furthermore, interferon alfacon1 also demonstrated significant antiviral activity in yield reduction and plaque reduction assays. The in vitro antiviral activity of interferon alfacon1 against SARS-CoV suggests continued evaluation of interferon alfacon1 as a therapeutic treatment for patients infected with SARS-CoV.

Fig. 1

Neutral red-stained cell cultures of a plaque reduction assay comparing the sensitivities of three isolates of SARS-CoV. Rows (A)–(C) show data of cells infected with the isolates TOR2, TOR7, and URBANI, respectively. The last column shows data from cells that were interferon alfacon1 treated but mock infected.

Fig. 2

Line graph of a yield-reduction experiment. Pfu/ml are plotted on the X-axis and time is plotted on the Y-axis. The open symbols are treated data and the closed symbols are sham-treated data. Each of the following shapes represents a different SARS-CoV isolate: the diamonds represent TOR2, the squares are TOR7, and the triangles are Urbani.

Fig. 3

Crystal violet-stained cell cultures of a yield-reduction experiment at 96 h postinfection. The first column shows treated and mock infected cells. The second column shows data from cells treated and infected with various isolates of SARS-CoV. The third column shows data from sham-treated and infected cells. The different isolates used for each row are noted on the right hand side of each row.