Markedly impaired production of PF4/heparin-specific antibody in B-cell–specific Notch2-deficient mice. A marked impairment of PF4/heparin-specific IgG production in B-cell–specific Notch2-deficient mice. CD19CreNotch2^+/+ and CD19Cre Notch2^fl/fl mice were immunized with mouse PF4/heparin complexes. Sera were collected at the indicated time points after immunization, and mouse PF4/heparin-specific total IgG level was measured by ELISA. The horizontal lines indicate the mean values. Data shown are obtained from 9 mice of each genotype.