In vitro depletion of anti–A carbohydrate determinant IgM-producing cells by A-BSA and anti-BSA Abs. (A) Balb/c mice were immunized twice with an intraperitoneal injection of 5 × 108 A-RBCs at a 1-week interval. At 8 days after the second immunization, the Spl cells from the immunized mice were incubated with various concentrations of A-BSA, as indicated. These cells were then incubated with rabbit anti-BSA Abs, followed by incubation with rabbit complement, as described in “In vitro depletion of anti-A Ab producing cells by using A-BSA, anti-BSA Abs, and complement.” Subsequently, the cells were subjected to ELISPOT assay to determine the frequency of anti-A IgM-producing cells. Average values (± SEM) for the individual groups are shown. (B) The relationship between the frequency of the remaining anti-A IgM-producing cells and the A-BSA concentrations used is shown (R2 = .871). The frequency of anti-A Ab-producing cells shown was determined by subtracting the number of dots produced by the cells in the wells coated with control BSA from the number of dots produced by the cells in the wells coated with A-BSA.
