Molecular evidence that SJL reticulum cell sarcomas are derived from pre-B cell. Clonal rearrangement of heavy chain but not of light chain immunoglobulin genes.
In order to investigate the clonal origin of SJL reticulum cell sarcoma (RCS), two-color cell membrane-staining and molecular biologic analyses were performed. Flow cytometric analysis revealed that the SJL RCS consists of about 50 to 60% Thy-1-positive and 20 to 30% B220-positive cells and that the majority of the Thy-1-positive cells are L3T4-positive, whereas a few are Lyt-2-positive. In spite of this pleomorphic nature of SJL RCS shown by cell membrane analysis, when the immunoglobulin heavy chain J segment (JH) was used to probe the DNA obtained from the tumor, we observed clonal rearrangements of the gene. Results of the cell-sorting experiment combined with Southern hybridization using the JH gene probe confirmed that those clonally expanding cells are Ia and B220 antigen-positive. Furthermore, all tumors derived from a given mouse showed the same rearrangement pattern. However, no clonal rearrangement was observed when the DNA was probed with the T cell receptor beta-chain gene or with immunoglobulin kappa- or lambda-light chain genes. From these data, we conclude that SJL RCS is a tumor of B cells and that the neoplastic event takes place at an immature B cell stage.
D000818:Animals; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000473:pathology*; D004273:DNA, Neoplasm / Q000235:genetics; D005434:Flow Cytometry; D005803:Genes, Immunoglobulin; D007143:Immunoglobulin Heavy Chains / Q000235:genetics*; D007147:Immunoglobulin Light Chains / Q000235:genetics*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000235:genetics / Q000473:pathology*; D051379:Mice; D008815:Mice, Inbred Strains; D011948:Receptors, Antigen, T-Cell / Q000235:genetics
D000911:Antibodies, Monoclonal; D004273:DNA, Neoplasm; D007143:Immunoglobulin Heavy Chains; D007147:Immunoglobulin Light Chains; D011948:Receptors, Antigen, T-Cell