A glycoprotein associated with the non-A, non-B hepatitis agent(s): isolation and immunoreactivity.

A glycoprotein was isolated and purified to homogeneity from the serum of a patient with chronic non-A, non-B hepatitis. NaDodSO4/PAGE of the glycoprotein revealed a single major band at Mr approximately 77,000. Antibodies to this glycoprotein were shown to possess the following immunoreactivity: (i) they reacted by radioimmunoassay with sera obtained at the time of diagnosis from 17 of 42 patients with non-A, non-B hepatitis and with only 2 of 58 sera from either matched controls or patients with hepatitis A or hepatitis B, (ii) they reacted with sucrose gradient fractions from a proven infectious non-A, non-B hepatitis serum at a peak density of 1.14 g/ml and in the soluble protein fractions on top of the gradient, and (iii) they reacted in ELISA with disrupted human T-cell lymphocytotropic virus type III (HTLV-III), and (iv) they reacted in immunoblots with a protein of Mr 74,000 derived from HTLV-III.