Figure 4.

Lack of B-1 cell replenishment in μ^−/− mice is recipient age dependent. Groups of recipient μ^−/− mice varying in age as indicated received 5 × 10⁶ PerC cells from C57/Igh^a donors. Control C57BL/6 neonates (first column) received PerC and were treated for 6 weeks with anti-IgM^b. PerC was analyzed for the presence of donor-derived B-1 cells by FACS (Fig.3A). Means ± SE of B-1 cells recovered 2–3 months after cell transfer or end of antibody treatment are shown. Serum IgM^a levels (means ± SE) were measured by ELISA.