| Description |
The objective was to develop a subunit vaccine against sarcoma induced by avian RNA tumor viruses. Envelope glycoproteins were removed from retroviruses Pr-A and Pr-C. The viral components were separated by sedimentation into two fractions: 8 Sand 4-6 S. The immunization capability of these viral subunits were evaluated in terms of tumor development, size and mortality. The 8 S fraction gave the best protection in terms of the three parameters when challenged with a lethal dose of tumor viruses; the protection was subgroup specific. In contrast, the 4-6 S fraction was only partially protective; protection was less subgroup specific. When challenged with inconsistent subgroups, the animals immunized with the 4-6 fraction were as minimally protected as unimmunized controls. This study shows that envelope glycoprotein fractions of the avian RNA tumor viruses can serve as immunogens and that protection is subgroup specific. It further shows that the 8 S subunit is superior to the 4-6 S fraction. |
