Isolation of immunogenic and suppressogenic glycoproteins from adenovirus type 12 hamster tumor cells.

Two types of glycoproteins were isolated from the membrane fraction of adenovirus type 12 (Ad12) hamster tumor cells by recovering detergent-solubilized glycoproteins using concanavalin A-affinity chromatography and gel filtration. One of the glycoproteins consisted of a polypeptide of 130,000 daltons (130K) with a pI value of 4.7-5.1, and the other consisted of a polypeptide of 18,500 daltons (18.5K) with a pI value of 6.3-6.6. The glycoproteins were immunologically different. The 18.5K glycoprotein induced in vivo resistance to tumor growth and anti-tumor cytotoxic T cells, while the 130K glycoprotein induced in vivo suppressor T cells which inhibited the activity of anti-tumor cytotoxic T cells.