Density Gradient Centrifugation Studies of Rubella Virus

Abstract

Summary

Rubella virus was grown in three different mammalian kidney cell lines. The resulting virus-containing supernates were concentrated by forced dialysis and were then studied for density on sucrose gradients. All of the virus preparations produced peaked infectivity bands with 99% of the infec-tivity concentrated in a band from 1.040 to 1.120 g/cm³. The peaks had an average density of 1.075 ± 0.005 g/cm³. Possible reasons for this low density are discussed. Severe conditions of centrifugation caused the formation of additional infectivity peaks at higher densities. Pelleted virus formed a very broad, low titered infectivity band without peaks. The results are similar to those obtained with other RNA lipid-containing viruses and support the view that rubella virus is physically similar to them.