A cell membrane "gp70" associated with Fv-4 gene: immunological characterization, and tissue and strain distribution.

Fv-4r is a dominant resistance gene which controls susceptibility of mice to exogenous infection with ecotropic murine leukemia virus (MuLV). A MuLV env-gene product related to gp70 on cells from uninfected Fv-4r mice has been found. Expression of this molecule is closely linked to the resistance allele. Antigenic determinants on the Fv-4r gp70 are similar to many ecotropic and some dualtropic MuLV gp70s but different from xenotropic and amphotropic MuLV gp70s. The Fv-4r gp70 molecule also has unique antigenic determinants since it is recognized by Fv-4 specific antisera which do not recognize other cell membrane gp70s or viral gp70s. The Fv-4-specific cell membrane gp70 is detectable on cells from thymus, spleen, lymph node, bone marrow, and embryo fibroblasts from Fv-4r mice, but not from Fv-4s mice. Slight differences in electrophoretic mobility of Fv-4r gp70 are found on different tissues. This unique cell membrane gp70 may be causally related to Fv-4 resistance.