A. Rosner et al., ANALYSIS OF LY-1-CELL POPULATIONS AND IGH REARRANGEMENTS IN NORMAL SPLEENS AND IN LYMPHOMAS OF AKR( B)J AND AKR FV-1(B) MICE/, Cancer research, 53(9), 1993, pp. 2147-2153
AKR mice are highly susceptible to development of spontaneous T-cell l
ymphoma. Thymus removal at the age of 1-3 months greatly reduces T-cel
l lymphoma. Lymphomas that have the characteristics of T- and/or B-cel
ls occur sporadically in peripheral lymphoid tissues of old thymectomi
zed AKR/J mice. These thymectomized mice were shown to carry dormant p
otential lymphoma cells. Transplantation of lymphoid cells from 8-12-m
onth-old AKR/J mice, thymectomized at the age of 6 to 8 weeks, into in
tact or thymectomized young recipients yielded 80-100% Ly-1+ pre-B or
B-cell lymphomas. In the AKR-Fv-1b congenic strain the Fv-1n allele of
AKR/J mice was substituted with the Fv-1b allele, thereby limiting vi
ral replication and spread of the endogenous N-tropic murine leukemia
virus. As a result of this restriction in virus spread, AKR-Fv-1b mice
develop a low spontaneous incidence (7%) of T-cell lymphomas and abou
t 28% of Ly-1+ B-cell lymphomas at old age. In spleens of 15-18-month-
old thymectomized AKR/J mice and intact AKR-Fv-1b mice, 30-60% of the
B-cells were of the Ly-1+ B type. Analysis of the IgH locus in these n
ormal old spleens and Ly-1+ B lymphomas indicated mono- or oligoclonal
ity. One particular IgH rearrangement was identified in many individua
l old spleens and tumors. A second specific IgH rearrangement was foun
d in some tumors. Possible mechanisms involved in the expansion of Ly-
1+ clones and their progression into tumors are discussed.