Table 2.

Absolute and Relative Numbers of Short- and Long-lived B Cells in the Spleens of Normal and Mutant Mice

	Short-lived	Long-lived	Short→long-lived
Control	5.6 (100%)	29.4 (100%)	0.9 (100%)
CD45−/−	37.8 (670%)	46.2 (157%)	0.8 (89%)
CBA/N	5.2 (92%)	4.8 (16%)	0.1 (11%)

The absolute number (× 10⁶) of labeled (short-lived) and unlabeled (long-lived) B cells in the spleens of control, CD45^−/−, and CBA/N mice was calculated after 3 d of continuous treatment with BrdU. The number of labeled B cells detected 18 d after the 3-d BrdU treatment period corresponds to the number of B cells that became long lived. Numbers of labeled and unlabeled B cells in mutant mice are given in parentheses as percentages of the numbers found in control mice .