Characterization of the immunophenotype and the metastatic properties of amurine T-lymphoma cell line. Unexpected expression of cytoplasmatic CD4

We report the first characterization of a mouse T-lymphoma cell line that s urprisingly expresses cytoplasmatic (cy) cyCD4. Phenotypically, LBC cells a re CD5(+), CD8(+), CD16(+), CD24(+), CD25(+), CD2(-/dim), CD3-(/dim), TCR b eta (-/dim), TCR-gamma delta (-), CD154(-), CD40(-), and CD45R(-). Coexpres s cyTCR beta, cyCD3, cyCD4, and yet lark surface CD4 expression. Transplant ation of LBC cells into mice resulted in an aggressive T-lymphoblastic lymp homa that infiltrated lymph nodes, thymus, spleen, liver, ovary, and uterus but not peripheral blood or bone marrow. LBC cells display a modal chromos ome number of 39 and a near-diploid karyotype. Based on the characterizatio n data, we demonstrated that the LBC cell line was derived from an early T- cell lymphocyte precursor. We propose that the malignant cell transformatio n of LBC cells could coincide with the transition stage from late double-ne gative, DN3 (CD4(-), CD8(-)CD44(-/low), CD25(+)) or DN4 (CD4(-/low), CD8(-/ low), CD44(-), CD25(-)) to double-positive (DP: CD4(+)CD8(+)) stage of T-ce ll development. LBC cells provide a T-lymphoblastic lymphoma model derived from a malignant early T-lymphocyte that can be potentially useful as a mod el to study both cellular regulation and differentiation of T-cells. In add ition, LBC tumor provides a short latency neoplasm to study cellular regula tion and to perform preclinical trials of lymphoma-related disorders.