Murine leukaemia virus gene product as an acute phase protein: complete suppression of serum gp70 synthesis in hepatocytes of B10.S mice.

The Sgp-1c trait is associated with H-2s and relates to the small content of serum gp70 as well as the lack of serum gp70 responsiveness to lipopolysaccharide (LPS). Northern hybridization of RNA from B10.S liver and its hybrid with NZB showed that the suppression of gp70 in Sgp-1c carrying mice can be regulated at the transcriptional level. However, the inheritance of this trait shows the complicated manner of segregation in certain crosses. All (B10.S x NZB) F1 hybrid mice and F1 x B10.S back-cross mice had low amounts of serum gp70 and did not respond to LPS with increased levels of serum gp70. In contrast, F1 x NZB back-cross progeny varied widely in serum gp70 levels. The serum gp70 levels of most F1 x NZB back-cross mice was increased by LPS, although the range of increases was broad. These results indicate that the Sgp-1c alone is not sufficient to lower serum gp70 levels, unless B10 background is present. The expression of Sgp-1 system, which is linked with the H-2 region, requires non-H-2-linked genes.