Masaru Nishikori

A Novel B Cell Line Established from Ki-1-positive Diffuse Large Cell Lymphoma

A novel cell line, designated KIS‐1, was established from a patient with Ki‐1‐positive diffuse large cell lymphoma. Multiple phenotypic analysis of the KIS‐1 cells was carried out with a total of 22 monoclonal antibodies defining hematopoietic cell subsets and lineages. The KIS‐1 cells were positive for Ki‐1, B4, HLA‐DR, and 2D1 (common leucocyte) antigens, but were negative for the antigens reportedly specific for T cells, natural killer cells, granulocytes, monocytes, interdigitating reticulum cells and dendritic reticulum cells. The genomic analysis of the KIS‐1 cells showed not only the rearrangement of JH and Jk genes but also the probable rearrangement of Cγ genes. Moreover, the cells produced immunoglobulin γ chains. Thus, KIS‐1 was considered to be of B‐cell lineage. The lymphoma‐cell derivation of KIS‐1 was based on the following facts. The cytochemical, immunologic, cytogenetic properties and the results of the molecular genomic analysis in the KIS‐1 cells were essentially the same as those of the original tumor cells, and the KIS‐1 cells were negative for Epstein‐Barr virus‐associated nuclear antigen. KIS‐1 is the only known B‐cell line derived from Ki‐1‐positive diffuse large cell lymphoma, and should be useful for defining the biological implications of Ki‐1 antigen.

Immunogenotypes of Lymphoid Malignancies; the Rearrangement of T Cell Receptor β Chain Gene Can Occur before the γ Chain Gene Rearrangement

Immunoglobulin (Ig) and T cell receptor (TcR) gene rearrangements were analyzed in 101 cases of lymphoid malignancies in association with a surface phenotype study. In leukemias/lymphomas with mature phenotype, there is a good correlation between phenotypes and genotypes. However, in leukemias/lymphomas with immature phenotype, we found many discordances between phenotypes and genotypes, suggesting the stochastic nature of hematopoietic cell differentiation at the early stage. As for TcR β and γ chains, the rearrangement of γ chain gene is considered to occur slightly prior to that of β chain gene. However, we observed a mature T cell malignancy, adult T‐cell leukemia, with rearranged β chain gene and germ line γ chain gene, showing the possible existence of another pathway of T cell differentiation.