PARP-14 regulates the balance of B-cell subsets and contributes to the IgA response to antigen. (A,B) Single-cell suspensions of splenocytes were analyzed as described in “Flow cytometry and apoptosis assays.” Shown are representative FACS profiles of cells in the B220⁺ gate using (A) CD21 versus CD23 or (B) IgM versus IgD to define distinct marginal zone and follicular B-cell subsets (MZB and FOB, respectively). A reproducible increase in basal CD23 levels on the surface of PARP-14 FOB cells was incidentally noted. (C) Role of PARP-14 in promoting the IgA antibody response to antigen. WT and PARP-14–null mice (6 weeks; n = 12) were immunized with KLH followed by measurement of the KLH-specific IgA response using capture enzyme-linked immunosorbent assay. The results are shown as absorbance value from these assays (*P < .05).