Figure 2.

Purified mouse gp75 mixed with lysates of wt/Sf9 cells does not induce autoantibodies to gp75. C57BL/6 mice were immunized with purified gp75 from B16 melanoma cells (purified gp75), purified gp75 from B16 melanoma cells mixed with lysates from 1 × 10⁶ Sf9 cells (purified gp75 + sf9), lysates of 1 × 10⁶ insect Sf9 cells infected with either recombinant baculovirus expressing syngeneic mouse gp75 (gp75/sf9 cells), or wt baculovirus (sf9 cells). Purified gp75 from B16 melanoma contained 10 μg of gp75, and gp75/Sf9 contained 14 μg of gp75. All immunizations included Freund’s adjuvant. Mice were immunized four times s.c. Sera from immunized mice were used to immunoprecipitate syngeneic gp75 from [³⁵S]methionine-labeled B16 melanoma lysates. The mAb TA99 was used as a positive control (left lane). Results for five mice in each group are shown (lanes 1–5).