[Preparation of ribonucleoproteins and virion envelopes of the Zaisan-260 and R-16225 strains of Semliki Forest virus antibody production].

Conditions for the preparation of subviral structures, envelope and ribonucleoprotein, of the Zaisan-260 and R-16225 strains of Semliki Forest virus inducing antibody response in rabbits inoculated into lymph nodes were developed. The virus was cultivated in chick embryo fibroblasts in a medium containing rabbit serum. Ribonucleoproteins and envelopes were isolated by virus disruption with Nonidet P-40 at 25 degrees C for 20 min followed by fractionation in a linear sucrose density gradient 15-30% at 150,000 X g for 50 min, and identification of envelopes and ribonculeoprotein by 14C and 3H labels. Rabbit immune sera to virions, envelope and nucleopsid fragments of the both Semliki Forest strains wer prepared. The immune sera to the intact virion had slightly higher antibody titres than sera to subunits.