FIG. 4.

CBH-2 HMAb precipitates only properly folded E1E2 complexes. HEK 293 cells were transfected with plasmid expressing E1E2p7NS2 or E1 alone and were lysed in the presence of iodoacetamide. Proteins from E1E2p7NS2 lysate were immunoprecipitated with CBH-2, the mouse anti-E1 (A4), or the mouse conformation-dependent anti-E2 (H53). Irrelevant mouse and human immunoglobulins were used as negative controls. Proteins from E1 lysate were immunoprecipitated with A4. Bound proteins and lysate E1E2p7NS2 (3 × 10⁵ cell equivalents, 10 times less than in immunoprecipitations) were analyzed by SDS-12% PAGE under nonreducing conditions followed by immunoblotting with A4. Results are representative of data obtained in two independent experiments. Mouse immunoglobulins (m Igs) are indicated. The reduced form (E1 red) and oxidized form (E1 ox) of E1 are indicated.