Rescue of serum Ig levels, TI-II responses, and BCR-dependent proliferative responses in MBS-treated BtkTec–/– mice. Engrafted recipients were immunized with TNP-Ficoll, bled, and analyzed for serum IgM, IgG3, and anti-TNP–specific IgM levels. (A) Kinetic data from individual animals in a representative experiment shows restoration of antibody production and TI-II levels by about 15 weeks after transplantation with MBS-transduced bone marrow cells. (B) IgM, IgG3, and anti-TNP IgM results from all experiments, analyzed between weeks 7 and 14 after transplantation, show significant improvement in MBS-treated animals versus BtkTec–/– controls. *Statistical significance, P < .01 for IgM, IgG3, and anti-TNP IgM. Anti-TNP IgG3 levels from weeks 13 to 21 are also shown (P < .0001). Mean serum antibody levels are indicated by a horizontal bar. Open versus closed circles denote results for mock-versus MIG-transduced BtkTec–/– animals, respectively. (C) Total splenocytes were harvested after transplantation, red blood cells lysed, and cultured with media alone (negative control), phorbol ester and ionomycin (positive control), LPS, or 2 doses of anti-IgM F(ab)2 antibody. Proliferative responses were measured by 3H-thymidine uptake. Results from a representative experiment (experiment 4) demonstrate restoration of LPS and anti-IgM responses in MBS-treated animals (P < .001 for MBS-versus MIG-treated animals for all stimuli). Analysis of data from experiments 1 to 3 also demonstrated statistically significant differences between MBS-treated mice (n = 7) and BtkTec–/– control mice (n = 5; P < .01 for 20 μg and P < .05 for 5 μg anti-IgM stimulation).
