Figure 5.

Ablation of the cellular isomer of the prion protein (PrP^C) specifically on follicular dendritic cells (FDC) has no effect on immunoglobulin class switching. Serum from mice immunized with dinitrophenyl–keyhole limpet haemocyanin (DNP‐KLH) was also analysed for titres of IgG subclasses to assess the level of class switching occurring in mice with PrP^C ablated on FDC in comparison to control groups. Serum was analysed at days 0, 7 and 21 but as early titres were low, only data from day 21 are shown. Titres of IgG1 in all transgenic lines were significantly higher than that measured in wild‐type (WT) controls (P < 0·001; a). CD21‐Cre single transgenic mice have significantly lower titres of IgG2a in comparison to other groups (*P < 0·001; b), however titres in CD21‐Cre Prnp^flox/− mice are not significantly different to those in WT or Prnp^flox/− lines (**P > 0·065; b). No significant differences in titre of IgG2b was observed between groups (P > 0·09; c). CD21‐Cre Prnp^flox/− mice have significantly higher titres of IgG3 in comparison to WT and single transgenic CD21‐Cre controls (*P < 0·001; d), however Prnp^flox/− mice have similar titres (**P = 1; d). Although there are some slight differences in IgG subclass titres between groups, no differences are specific to mice with PrP^C ablated in FDC and therefore ablation of PrP^C in FDC does not appear to have any specific effects on immunoglobulin class switching after immunization.