Lack of B cell leakiness in BALB/cA-nu, scid double mutant mice

BALB/cA mice homozygous for both nu and scid mutations (BALB/cA-nu/nu, scid /scid) were developed by mating between BALB/cA-scid and BALB/cA-nu. These mice have greater longevity than C.B-17-scid because no thymic lymphoma occ urs in them unlike in the latter C.B-17-scid is known to show the leaky phe nomenon in which a few clones of functional T and B cells develop in aged C .B-17-scid. Unexpectedly, the leaky B cells and T cells were absent or supp ressed in BALB/cA-nu, scid mice when cytokine expressions were determined b y RT-PCR, lymphocyte phenotypes by flow cytometry and serum immunoglobulin levels by ELISA. These results indicate that B cell leakiness may be induce d by leaked T cells. BALB/cA-nu, scid mice may be useful as a recipient in allo- and xeno-transplantation experiments because of the absence of both t hymic lymphomas and leakiness, in addition to lack of hair.