Table 1.

Comparison of [³H]thymidine Incorporation in F1 (xid.bcl-x) and xid Mice

Mouse		[3H]thymidine* incorporation		Transgene		Btk‡		Phenotype
Female F1  (xid.bcl-x-87)		15,489		yes		+/−		non-xid
Female F1  (xid.bcl-x-87)		12,300		yes		+/−		non-xid
Female F1  (xid.bcl-x-81)		14,032		yes		+/−		non-xid
Female F1  (xid.bcl-x-81)		11,089		yes		+/−		non-xid
Male F1  (xid.bcl-x-87)		7,050		yes		−		xid
Male F1  (xid.bcl-x-87)		6,500		yes		−		xid
Male F1  (xid.bcl-x-81)		1,200		yes		−		xid
Male F1  (xid.bcl-x-81)		1,999		yes		−		xid
Male xid 1		2,000		na		−		xid
Male xid 2		1,524		na§		−		xid

^*2 × 10⁵ B cells were stimulated for 48 h with 25 μg/ml anti-IgM and pulsed for the final 4 h with 1 μCi [³H]thymidine.  

^‡+ indicates presence of wild-type Btk; − indicates presence of mutant Btk. Since Btk is an X-linked gene, males carry only one allele.  

^§na, not applicable.