Enterovirus Concentration on Cellulose Membranes

Abstract

Cellulose nitrate membranes were used as one of the adsorbents in concentrating viruses from water. For adsorption to occur, salts were required. With increase in valency of salt, less salt was necessary for enhanced virus adsorption to membranes. Trivalent salts were more effective because they could be used at only 1% the concentration required for divalent salts. Thus, 0.5 mm AlCl3 was as effective as 50 mm MgCl2. For testing 500 gal of water, only 0.24 kg of AlCl3 was required in contrast to 20 kg of MgCl2. Virus could then be eluted from such membranes, having an area of 486 cm2, with 250 ml of pH 11.5 buffer. Lowering the pH of the eluate and adding AlCl3 permitted the virus to be quickly readsorbed on a smaller cellulose membrane, i.e., 4 cm2. Virus for assay was eluted from the small membrane in 1 ml. This procedure has provided the basis for concentrating minute amounts of virus from large volumes of water. Cliver (2, 3) and Wallis and Melnick (9) reported on the use of cellulose membranes for the concentration of viruses. The parameters for virus adsorption to and elution from cellulose membranes were delineated (10), and such membranes were employed for detection of viruses in natural waters (11). Other investigators have adopted the method for concentrating viruses from water (4-7). An apparatus was recently described which can concentrate virus from 400 gal of water onto cellulose membranes in 1 hr (8). The procedure required a 5-gal vessel containing 4 M MgCl2. The salt was injected into the flowing water to make a final concentration of 0.05 M, which is necessary for virus adsorption to the membrane. Thus, 20 kg of MgCl2 had to be used for each test. This salt had been selected because of its high solubility. The current investigation was undertaken to determine the effects of other highly soluble salts on virus adsorption to cellulose membranes in order to make the concentration of virus from large volumes of water more practical.

Concentration of Enteroviruses from Large Volumes of Water

“…The modified procedures used for virus concen- a Based upon assay of the stock poliovirus added to 100 gallons of tapwater. tration has advantages over the previously described procedure (5,8) because the elimination of clarifying filters makes it less expensive, and the elimination of salt addition makes it operationally easier. When tested with small quantities of virus in 100-gallon volumes of tapwater, this modified unit was capable of concentrating the viruses nearly 40,000-fold with an average recovery efficiency of 77%.…”

“…These results were attributed to the fact that, in the presence of excess hydrogen ions, interfering organic compounds were not able to compete for membrane surface sites required by the virus. Recently, we showed that the use of salts for concentrating viruses from water in the field could be made logistically practical by the use of AlClI, a trivalent cation salt which required 100to 200-fold less salt concentration than divalent cation salts for virus attachment to membranes or textile filters (5). Studies with insoluble polyelectrolytes revealed that salts interfered with virus adsorption at increased hydrogen ion levels (6,11).…”

Cellulose-based virus-retentive filters: a review

“…[ Na ? ) (Wallis et al 1972). Acidification of the viral suspension also improved virus adsorption efficiency, even in the absence of exogenously added salts (Sobsey et al 1973).…”

Concentration of Bacteriophages from Natural Waters

“…In the last decade considerable anxiety has been caused by contamination of potable waters by animal viruses and this has led to the development of methods for detecting small numbers of viruses in large volumes of drinking water. With few exceptions these methods have been specifically designed to detect acid-resistant enteroviruses, usually poliovirus, and generally use adsorption to various filters at pH 3-0-3-5 followed by elution of the viruses in a small volume of buffer-pH 10-5-1 1.5 (Wallis, Henderson & Melnick 1972;Sobsey et al 1973; Hill et al 1974; Jakubowski et al 1974;Jakubowski et al 1975;Farrah et al 1976; Hill et al 1976; Katzenelson et al 1976; Farrah et a2. 19776).…”