In vitro synthesis of beta1C/beta1A globulin (the C3 component of complement) by tissues and leucocytes of mice.

The synthesis of beta1C/beta1A globulin (the C3 component of complement) was studied in in vitro cultures of mouse tissues and leucocytes. Often culture in medium containing 14C-labelled amino acids, the newly synthesized radioactively-labelled protein was identified by radioimmunoelectrophoresis. Synthesis was found in spleen, liver, trachea, lung and Peyer's patch tissue, but was only occasionally detectable in cultures of intestine. Cultures of the glass-adherent cells from bone marrow, blood, lung washings and subcutaneous tissue all showed strong synthesis, indicating that the ability to synthesize beta1C/beta1A is a property shared by mononuclear phagocytes from many sites. In contrast, the nonglass adherent cells showed no synthesis of beta1C/beta1A, although these cells were shown to be viable by their ability to synthesize immunoglobulins.