Interaction of Respiratory Syncytial Virus with Polyions: Enhancement of Infectivity with Diethylaminoethyl Dextran

The infectivity of RS virus was enhanced by the addition of DEAE dextran to the virus inoculum or in the mixture. The maximal effect (2- to 5-fold) was obtained with 30 μg/ml in HEp-2 cells and 10 μg/ml in AGMK cells in the virus inoculum. The enhancing action of this polyion with RS virus was apparently exerted at the early stages of virus-cell interaction and involved direct complexing with virus particles. Although protamine sulfate enhanced the infectivity in the mixture as much as DEAE dextran, it inhibited the infectivity to 50% at a concentration of 60 μg/ml after a slight increase with 5-10 μg/ml in the virus inoculum. Dextran sulfate and heparin decreased markedly the infectivity of the virus (28 and 18%) with a concentration as low as 5 μg/ml in the virus inoculum in HEp-2 cells, and also showed an inhibitory effect in the mixture.