Morphology of IgD⁺CD38⁻CD23⁻CD71⁺ cells is unique among B-cell subpopulation and is generated by T-cell coculture using naive B cells. (A) B-cell subpopulations were prepared by cytospin and Giemsa staining. Cells are magnified 800×. (B) Bm1, Bm2, and IgD⁺CD38⁻CD23⁻CD71⁺ cells were cultured with cross-linking anti-IgM and with or without OKT3-stimulated, irradiated T cells. CD71⁺CD23⁻ cells were identified after 7 days. Results are representative of 5 experiments. (C) IgD⁺CD38⁻CD23⁻CD71⁺ cells from the same cocultures in panel B were evaluated for the loss of IgD expression. Percents represent the percent of cells within the given dot plot.