Abstract
Lymphocytic choriomeningitis (LCM) virus interfering particles were enriched relative to infectious virions by ultracentrifugation in a shallow gradient made of Urografin. Electrophoretic analysis revealed that they lacked the small (S) 23S RNA as well as GP-1 and GP-2 of the infectious virion and also lacked a newly characterized glycoprotein of apparent mol. wt. 85 x 103; instead, they contained a novel glycoprotein with mol. wt. 65 x 103.