Strain-related variation in the interaction of ferritin-conjugated plant lectins with mouse mammary tumor viruses.

Fernitin-conjugated plant lectins of varying sacchanide specificities were used to characterize oligosacchanides present on the surface of mouse mammary tumor virus (MMTV) produced in cells of mammary tumors of mice of C3H/He/Tex, A/Dm, and RlII/Dm strains. Mouse mammary tumor (MMT) cells grown on discs of FEP Teflon were labeled in situ with fennitin conjugates of concanavalin A specific for a-D-glucoand a-D-mannopyranosyl residues, wheat germ agglutinin specific for 2-acetamido-2-deoxy-oglucopyranosyl residues, and Ricinus communis agglutinin I specific for o-galactopynanosyl residues. Electron micro scopic examination revealed quantitative differences in binding of fennitin conjugates of wheat germ agglutinin and concanavalin A to C3H/He/Tex, A/Dm, and Rlll/Dm MMTV. No strain-related differences in labeling of MMTV by fennitin conjugated A. communis agglutinin I were observed. Statis tical analysis of labeling by fennitin-conjugated wheat germ agglutinin (Fen-WGA) indicated that there was a dense, uniform distribution of Fer-WGA on all 3 strains of MMT cells. However, plasma membranes of C3H/He/Tex and A/ Dm MMT cells were unlabeled on only weakly labeled by Fer-WGA at virus budding sites. No major antigenic differ ences between C3H/He/Tex and RlIl/Dm or A/Dm strain MMTV could be detected by immunoelectron microscopy. These results suggest the existence of strain-related vania tions in MMTV envelope oligosacchanide determinants and also indicate that virus-specific oligosacchanide determi nants are present in cellular plasma membranes in the early stages of virus assembly.