Immunologic characterization of gp70 and gp45 from Rauscher murine leukemia virus.

The envelope glycoproteins gp70 and gp45 were purified from Rauscher leukemia virus and compared in radioimmunoassay and gel diffusion using antibody to the purified proteins and a cross-reactive antibody prepared against feline leukemia virus. Previous studies indicated that gp70 and gp45 had very similar polypeptide components and differed mainly in carbohydrate content. The current studies indicate that gp70 contains the major antigenic determinants of gp45, and, in addition, determinants unique to gp70. We presume that these differences involve the carbohydrate components, either directly or indirectly by influence on conformation. The major antigenic deficiencies in gp45, relative to gp70, appeared to be in interspecies reactivity.