Cytogenetic findings in mouse multiple myeloma and Waldenström's macroglobulinemia

Multiple myeloma (MM) and Waldenström's macroglobulinemia-like lymphoma (MW) appear spontaneously in C57BL/KaLwRij mice at a frequency of 0.5% and 0.2%, respectively. They can readily be propagated by intravenous transfer of mainly bone marrow or spleen cells into syngeneic recipients. Previous studies demonstrated that these mouse malignant monoclonal gammopathies (MMG) show clinical and biologic features that closely resemble those of the corresponding human diseases and thus could be used as experimental models. We report on cytogenetic analysis of two mouse MW and five MM in vivo cell lines of the 5TMM series propagated in syngeneic mice. These studies demonstrated clonal abnormalities in all cell lines, hyperdiploid karyotype in both MW and one MM lines, and hypotriploidy, hypertriploidy, or hypotetraploidy in the other lines. Structural abnormalities of chromosome 15 were observed in all MM lines. In the five MM lines, frequent rearrangements were also found for chromosome numbers 1, 2, 5, and 12. A single chromosomal abnormality, as found in induced mouse plasmacytomas and resembling Burkitt lymphoma, was not found in mouse MM and MW. It was concluded that spontaneously originating C57BL MM of the 5T series is a better model for human MM than pristane-induced BALB/c or NZB plasmacytoma

Older Human B Cells and Antibodies

B cells have a number of different roles in the immune response. Their excellent antigen presentation potential can contribute to the activation of other cells of the immune system, and evidence is emerging that specialized subsets of these cells, that may be increased with age, can influence the cell-mediated immune system in antitumor responses. They can also regulate immune responses, to avoid autoreactivity and excessive inflammation. Deficiencies in regulatory B cells may be beneficial in cancer but will only exacerbate the inflammatory environment that is a hallmark of aging. The B cell role as antibody producers is particularly important, since antibodies perform numerous different functions in different environments. Although studying tissue responses in humans is not as easy as in mice, we do know that certain classes of antibodies are more suited to protecting the mucosal tissues (IgA) or responding to T-independent bacterial polysaccharide antigens (IgG2) so we can make some inference with respect to tissue-specific immunity from a study of peripheral blood. We can also make inferences about changes in B cell development with age by looking at the repertoire of different B cell populations to see how age affects the selection events that would normally occur to avoid autoreactivity, or increase specificity, to antigen