Viral IL-6 in the culture supernatants of BCBL-1 and BC-1 cells detected by immunoblotting with a specific rabbit antiserum. (A) A rabbit antiserum to vIL-6 was used in immunoblotting of viral and human IL-6 protein. (B) Conditioned medium from the BCBL-1 and BC-1 cell lines (1 mL) was TCA-precipitated and then analyzed by immunoblotting with a rabbit antiserum to vIL-6. Cell lysates from NIH3T3 cells (1 × 10³ cells) transfected with a control vector or with the vIL-6 gene were used as controls. (C) Detection of purified recombinant vIL-6 (0.32 to 200 ng) in immunoblotting using a rabbit antiserum to vIL-6.