title: Abnormal bone marrow B-cell differentiation in pre-B lymphoma-prone SL/Kh mice.
abstract: SL/Kh mice spontaneously develop pre-B lymphomas with surface phenotypes of B220+, BP-1+, Thy-1-, and surface immunoglobulin negative. The immunoglobulin heavy chain of lymphoma is clonally rearranged but the light chain gene remains in germline configuration. Studying prelymphoma stage SL/Kh bone marrow (BM), we found unusual multiclonal expansion of BP-1+ pre-B cells [34.8 +/- 5.8% (mean +/- SD)] by 4 weeks of age, whereas there were far fewer of such cells in most other laboratory strains (8 +/- 5%). The BP-1+ cells did not express surface immunoglobulin, Thy-1.1, or c-kit. Therefore, they seemed to belong to the pre-B II category. Increased numbers of BP-1+ cells were seen in F1 hybrids between SL/Kh and NFS/N; thus it was apparently a dominant heritable property of SL/Kh mice. Emergence of this population was independent of expression of endogenous ecotropic virus, since they were present in BMs of the F1 hybrid to C4W (Fv-4') and were not inhibited by neonatal injection of maternal resistance factor. In the radiation chimeras SL/Kh-->BALB/c, BP-1+ cells appeared abundantly (29.0 +/- 3.8%), whereas in the reciprocal chimeras BALB/c-->SL/Kh, for fewer (5.5 +/- 2.3%) appeared. Therefore, expansion of BP-1+ cells in prelymphomatous BM is a property of SL/Kh stem cells rather than BM microenvironments.
authors.affiliation: Department of Pathology, Faculty of Medicine, Kyoto University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Okamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Yamada
authors.forename: M S
authors.initials: MS
authors.lastname: Ogawa
authors.forename: S
authors.initials: S
authors.lastname: Toyokuni
authors.forename: Y
authors.initials: Y
authors.lastname: Nakakuki
authors.forename: H
authors.initials: H
authors.lastname: Ikeda
authors.forename: O
authors.initials: O
authors.lastname: Yoshida
authors.forename: H
authors.initials: H
authors.lastname: Hiai
mesh_terms: D000818:Animals; D001853:Bone Marrow / Q000473:pathology*; D002454:Cell Differentiation; D002678:Chimera; D009052:Leukemia Virus, Murine / Q000302:isolation & purification; D016393:Lymphoma, B-Cell / Q000382:microbiology / Q000473:pathology*; D051379:Mice; D008815:Mice, Inbred Strains; D010641:Phenotype; D011230:Precancerous Conditions / Q000382:microbiology / Q000473:pathology*