Cell lines with spontaneous secretion of pregnancy-associated alpha 2-globulin

Pregnancy-associated alpha 2-globulin (PA alpha 2G) was quantitated by radioimmunoassay in culture media from 34 exponentially growing human cell lines. Only 8/34 cell lines produced PA alpha 2G. The highest secretion was found in cell lines of histiocytic lymphoma origin while it was low in some carcinoma-derived lines. The results may support an assumption that PA alpha 2G is a normal cell product of B-lymphoid, monocytic and epithelial cells but may also simply indicate that ectopic PA alpha 2G production is especially common in tumors derived from such cells. The availability of PA alpha 2G-producing cell lines should facilitate studies of the immunoregulatory role of this protein.