Fig. 5.
Defective early hapten-specific antibody responses after cotransfer of naïve SH2D1A-/- B cells with naïve wt CD4+ cells. (a) Outline of the experiment. CD4+ cells (5 × 106) together with 10 × 106 B cells from unprimed SH2D1A-/- BALB/cor wt BALB/c mice were transferred into Rag2-/- mice and immunized with NP-KLH in alum at day 0 (d 0). Four combinations of CD4 and B cells were used to reconstitute the Rag2-/- recipients: [CD4+/+ B+/+], [CD4+/+ B-/-], [CD4-/-B+/+], and [CD4-/- B-/-], in which [-/-] represented SH2D1A-/- and [+/+], wt. Serum antibody levels responses were determined at day 10 (d 10), and mice were killed at day 20 (d 20) for analysis. (b) Analysis of IgM and IgG hapten-specific antibody responses at day 10. High-affinity [NP(3)-specific] IgM (Left) and IgG (Right), NP-specific antibody titers in the serum of recipient mice (n = 3) were determined as described in Materials and Methods (n = number of mice tested per experiment). Low-affinity [NP(24)-specific] IgM and IgG NP-specific antibody titers are shown in Fig. 9b. Results are representative of two independent experiments. Results of ELISAs are shown (y axis, OD 405 units; x axis, fold dilutions). -/-, cells derived from SH2D1A-/- mice; +/+, cells derived from wt mice; open squares, mice reconstituted with CD4+/+ B+/+ cells; filled squares, mice reconstituted with CD4+/+ B-/- cells; open circles, mice reconstituted with CD4-/- B+/+ cells; filled circles, mice reconstituted with CD4-/- B-/- cells.