Figure 4.

Adoptive transfer of purified emergent B220⁺ and B220⁻ memory B cells. (A) 4 × 10⁷ unfractionated spleen cells from animals 4 d after rechallenge were injected into the tail vein of C57BL/6 Rag-1–deficient animals by intraperitoneal injection with 50 μg NP-KLH (no adjuvant). The first panel represents the NP and IgD profiles of the spleen cells that were transferred. The second panel represents the CD138 and B220 profiles of the NP⁺IgD⁻ cells in these animals (percentage of NP-specific cells in total spleen cells before transfer is indicated above inset). The percentage of NP⁺IgD⁻ cells after transfer (of total spleen cells in recipient) is displayed in the next column, and the third panel represents the CD138 and B220 profiles of the NP⁺IgD⁻ cells in the spleens of the Rag-1–deficient mice 5 d after transfer. (B) The first two panels present reanalysis of spleen cells from day 4 memory mice, excluding NP⁺IgD⁻ and all CD138⁺ cells at the time of sorting. 5–8 × 10⁶ spleen cells sorted this way (NP⁻ spleen) were injected into the tail vein (with Ag intraperitoneally as above), and spleen cells from Rag-1–deficient donors analyzed 5 d after transfer (third panel). (C) 2–6 × 10⁴ purified NP⁺IgD⁻CD138⁻ that were B220⁺ (top) or B220⁻ bottom) were added to 5–8 × 10⁶ NP⁻ spleen cells before adoptive transfer. The first two panels in each set are the reanalysis of the cell mixture immediately before transfer, and in the last panel are the CD138 and B220 profiles of the NP⁺IgD⁻spleen cells in the Rag-1–deficient recipients 5 d after transfer. (D) Mean ± SEM from three adoptive transfer experiments displaying the proportion of the three subsets recovered after transfer. The level of NP⁺ events after transfer of the NP⁻ spleen cells alone was negligible, so they are not included in this table. (E) Summary of cell recovery and Ab production during time of transfer (n = 2 or 3 animals). Cell recovery was calculated as the percent of NP-specific cells recovered divided by the number transferred. N/A indicates not applicable, as the number of NP-specific cells transferred and recovered was negligible. The relative titer of NP-specific Ab is displayed as the titer of serum that produced an OD of 1.4 OD units (maximum of 4.0 OD units).