Nonspecific adsorption of proteins to microplates

Using 96-well tissue culture polystyrene plates and a fluorescence plate reader as tools to study the survival and inactivation of viruses on surfaces

A method for studying the behavior of viruses on surfaces has been developed and is illustrated by determining the temperatures that inactivate adsorbed viral hemorrhagic septicemia virus (VHSV) and the concentration of 1-propanol that disinfected surfaces with adsorbed VHSV and chum salmon virus (CSV). VHSV is a rhabdovirus; CSV, a reovirus, and they were detected with two fish cell lines, EPC and CHSE-214, respectively. When polystyrene tissue culture surfaces were incubated with virus, rinsed, and left to dry, they still supported the attachment and spreading of cell lines and after 7 days these cells showed the characteristic CPE of the viruses. Thus cells appeared to be infected directly from surfaces on which viruses had been adsorbed. Applying this property to 96-well plates allowed duplicate surfaces to be examined for their infectiousness or support of CPE. For each treatment 80 replicate surfaces in a 96-well plate were tested at one time and the results expressed as the number of wells showing CPE. VHSV adsorbed to polystyrene was inactivated by drying in the dark at temperatures above 14 °C, but remained infectious for at least 15 days of drying at 4 °C. For chemical sterilization of polystyrene surfaces with adsorbed virus, disinfection was achieved with 1-propanol at 40% for VHSV and at 60% for CSV. As CPE can be conveniently monitored in 96-well plates with a fluorescence plate reader, this method can be used to rapidly evaluate a variety of treatments for their ability to inactivate surface-bound viruses.

Microtiter assay for interferon: microspectrophotometric quantitation of cytopathic effect

This report describes an accurate, reproducible, and efficient microassay for human interferon, using a dye-uptake method to quantitate cytopathogenicity. The antiviral activity was measured by using a Gilford 300-N microsepctrophotometer, with the automatic programmer, sampler, and data lister. Two hundred interferon samples, each in a final volume of 1.0 ml, may be analyzed and recorded in 45 min. The reproducibility of a laboratory reference interferon and the human international reference B 69/19 on two different cell lines, using the model Q Oxford sampler, was found to be excellent, with the standard error of the log10 geometric mean of both references +/- 0.04 to 0.06.