Production of PF4/heparin-specific antibodies by MZ B cells adoptively transferred into μMT mice. (A) Production of PF4/heparin-specific antibodies by MZ B cells, but not FO B cells, adoptively transferred into μMT mice. Partially irradiated μMT mice were adoptively transferred with FACS-sorted wild-type MZ B cells (MZ + μMT) (n = 6), FO B cells (FO + μMT) (n = 6), or no B cells (μMT) (n = 4), and were then immunized with mouse PF/heparin complexes. Sera were collected at the indicated time points after immunization. Total PF4/heparin-specific IgG level was measured by ELISA. The horizontal lines indicate the mean values. Data shown are obtained from 2 independent experiments. (B) Production of NP-specific antibodies by FO B cells adoptively transferred into μMT mice. Partially irradiated μMT mice were adoptively transferred with FACS-sorted wild-type FO B cells (FO + μMT) (n = 4) or no B cells (μMT) (n = 4), and were then immunized with the T-cell-dependent-antigen NP-CGG. Sera were collected at the indicated time points after immunization. NP-specific IgG1 levels were measured by ELISA. The horizontal lines indicate the mean values. (C) PF4/heparin-specific IgG2b and IgG3 production by MZ B cells adoptively transferred into μMT mice. The different isotypes of PF4/heparinspecific antibodies in the sera from (A) were measured by ELISA. The horizontal lines indicate the mean values.