Preferential binding of mouse mammary tumor virus to B lymphocytes

Mouse mammary tumor virus (MMTV) has been shown to preferentially infect B lymphocytes in vivo. We have used recombinant envelope-coated fluospheres a nd highly purified MMTV particles to study the distribution of the viral re ceptors on fresh mouse lymphocytes. A preferential dose-dependent binding t o B lymphocytes was observed which could be competed with neutralizing anti bodies. In contrast, T-lymphocyte binding remained at background levels. Th ese results strongly suggest a higher density of viral receptor molecules o n B lymphocytes than on T lymphocytes and correlate with the preferential i nitial infection of B lymphocytes observed in vivo.