T-cell Chronic Lymphocytic Leukemia Cells Research Articles

Characterization of a new T-lineage glycoprotein expressed in mature T- cell leukemias and lymphomas

We identified a new human, T-lineage restricted glycoprotein of molecular weight 120 Kd that is expressed primarily in mature T-cell malignancies. The antigen, named TCA-1 (T-cell cytoplasmic antigen), is an intracellular glycoprotein found mainly in the Golgi stacks, although a few cell lines also display surface membrane TCA-1. Many but not all T-cell neoplasms express this antigen. The antigen is absent from neoplastic and normal human tissue outside the T-lymphocyte lineage. TCA-1 was identified by murine monoclonal antibodies produced after immunization of mice with T-cell chronic lymphocytic leukemia cells. The glycoprotein is a monomer containing approximately 4% N- linked carbohydrate with terminal D-galactose residues. Partial amino acid sequence analysis of TCA-1 shows homology with an immunoglobulin heavy chain region, which suggests that TCA-1 may belong to the immunoglobulin supergene family of receptor and adhesion molecules.

Characterization of a New T-Lineage Glycoprotein Expressed in Mature T-Cell Leukemias and Lymphomas

We identified a new human, T-lineage restricted glycoprotein of molecular weight 120 Kd that is expressed primarily in mature T-cell malignancies. The antigen, named TCA-1 (T-cell cytoplasmic antigen), is an intracellular glycoprotein found mainly in the Golgi stacks, although a few cell lines also display surface membrane TCA-1. Many but not all T-cell neoplasms express this antigen. The antigen is absent from neoplastic and normal human tissue outside the T-lymphocyte lineage. TCA-1 was identified by murine monoclonal antibodies produced after immunization of mice with T-cell chronic lymphocytic leukemia cells. The glycoprotein is a monomer containing approximately 4% N-linked carbohydrate with terminal D-galactose residues. Partial amino acid sequence analysis of TCA-1 shows homology with an immunoglobulin heavy chain region, which suggests that TCA-1 may belong to the immunoglobulin supergene family of receptor and adhesion molecules.

Gene encoding human p250 T-cell activation antigen maps to human chromosome 11.

Human p250 T-cell activation antigen detected by a monoclonal antibody, B1.19.2, is a single peptide antigen with a molecular weight of 250 kilodaltons and is classified serologically into cluster of differentiation, CDw26. Concordance between the presence of human chromosome 11 and the reactivity with B1.19.2 was demonstrated by chromosomal analysis of 23 clones derived from three hybrid series obtained from the fusion of human activated lymphocytes or T-cell chronic lymphocytic leukemia cells and BW5147 mouse T-cell leukemic cells. The results indicated that the presence of chromosome 11 was essential for the expression of p250 T-cell activation antigen. Moreover, the gene for this antigen was assigned to chromosome 11pter----p11.2 by analysis of the hybrid clones retaining the translocated chromosome of 11.

Chromosomal assignments of genes coding for human leukocyte common antigen, T-200, and lymphocyte function-associated antigen 1, LFA-1 beta subunit.

Five hybrids reactive with monoclonal antibodies against human leukocyte common antigen (T-200) and/or lymphocyte function-associated antigen 1 (LFA-1) beta subunit were obtained from the fusion of human blood lymphocytes or T-cell chronic lymphocytic leukemia cells with BW5147 mouse T-cell leukemia cells. Chromosome analyses of 20 clones showed concordance between the presence of human chromosomes 1 and 21 and the expression of T-200 and LFA-1 beta subunit, respectively. Confirmation of human chromosomes in the hybrids was made by the electrophoretic analyses of phosphoglucomutase for chromosome 1 and superoxide dismutase for chromosome 21. The results suggested that the presence of human chromosomes 1 and 21 was essential for the expression of T-200 and LFA-1 beta subunit, respectively.

Expression of interleukin-2 receptor on T cell chronic lymphocytic leukemia cells and their response to interleukin-2

We analyzed peripheral blood leukemic cells from six patients with T cell chronic lymphocytic leukemia (T-CLL) with monoclonal antibodies including the anti-Tac antibody, which recognizes the receptor for interleukin 2 (IL 2). The patients were divided into two groups according to the reactivity of the monoclonal antibodies. Leukemic cells from three patients with T-CLL reacted with OKT3 and T4 but not T8, whereas those from the remaining three patients reacted with OKT3 and T8 but not T4. IL 2 receptor, which is expressed on activated T cells but not on resting T cells, was preferentially expressed on T4+ T-CLL cells. The IL 2 receptor on T4+ T-CLL cells was indistinguishable from that on normal activated T cells with respect to molecular weight and downregulation by the anti-Tac antibody. Moreover, fresh T4+ T-CLL cells, but not T8+ T-CLL cells, proliferated in response to exogenous IL 2 without prior activation, and this proliferation was inhibited by the anti-Tac antibody. These results suggest that malignant growth of T4+ T-CLL cells can be regulated by IL 2 not only in vitro but also in vivo.

Expression of Interleukin-2 Receptor on T Cell Chronic Lymphocytic Leukemia Cells and Their Response to Interleukin-2

Abstract We analyzed peripheral blood leukemic cells from six patients with T cell chronic lymphocytic leukemia (T-CLL) with monoclonal antibodies including the anti-Tac antibody, which recognizes the receptor for interleukin 2 (IL 2). The patients were divided into two groups according to the reactivity of the monoclonal antibodies. Leukemic cells from three patients with T-CLL reacted with OKT3 and T4 but not T8, whereas those from the remaining three patients reacted with OKT3 and T8 but not T4. IL 2 receptor, which is expressed on activated T cells but not on resting T cells, was preferentially expressed on T4+ T- CLL cells. The IL 2 receptor on T4+ T-CLL cells was indistinguishable from that on normal activated T cells with respect to molecular weight and downregulation by the anti-Tac antibody. Moreover, fresh T4+ T-CLL cells, but not T8+ T-CLL cells, proliferated in response to exogenous IL 2 without prior activation, and this proliferation was inhibited by the anti-Tac antibody. These results suggest that malignant growth of T4+ T-CLL cells can be regulated by IL 2 not only in vitro but also in vivo.

Phenotypic and functional characterization of HTLV positive neoplastic T cells cultured with interleukin-2 — I. Retention of morphology, phenotype and selective cytotoxic properties in long term culture

T cells from the peripheral blood of a T-cell chronic lymphocytic leukemia (T-CLL) patient, cultured in the presence of interleukin-2 (IL-2), were found to express the p19 structural core protein of the human T-cell leukemia/lymphoma virus (HTLV) and to release type C virus particles. Comparison of the T-CLL cell line with the original leukemic T cells revealed that both the fresh and the proliferating T-CLL cells were pleomorphic cells that showed a convoluted nucleus and formed rosettes with sheep erythrocytes (E-rosettes). They were reactive with the monoclonal antibodies OKT1, OKT4 and OKT11, but not with OKT3, OKT6 or OKT8, indicating that they were mature T cells but that they differed from normal T cells in their lack of reactivity with OKT3. In addition they did not bind peanut agglutinin or OKM-1, and were negative for Epstein-Barr nuclear antigen, surface immunoglobulin, non-specific esterase activity or Fc- or complement receptors. Part of the fresh T-CLL cells reacted with a monoclonal antibody recognizing HLA-DR antigens (p29, 34) (36%) and with anti-Tac (62%), a monoclonal antibody directed at the IL-2 receptor, indicating that the T-CLL cells were partially activated already in vivo. After culture in vitro all proliferating T-CLL cells expressed HLA-DR and Tac antigens. The fresh T-CLL cells were found to be defective in cell-mediated lympholysis (CML) generated in mixed lymphocyte culture (MLC), antibody-dependent cellular cytotoxicity (ADCC) and lectin-dependent cellular cytotoxicity (LDCC). In addition they failed to exhibit natural killer (NK) cell activity against targets that are usually very susceptible to lysis, such as K562, but were able to kill two tumor-derived cell lines, the melanoma NKI-4 and the neuroblastoma CHP-100. The same pattern of selective killing was observed using the proliferating T-CLL cells as effectors, or cloned T-CLL cultures obtained from them by limiting dilution procedures. Therefore, it was concluded that the T-CLL cells represented a clonal expansion of neoplastic T cells that retained their phenotype and cytotoxic properties after culture in vitro.

Phenotypic and functional characterization of HTLV positive neoplastic T cells cultured with interleukin-2 — II. Inhibition of lymphoproliferative responses

T cells from the peripheral blood of a T-cell chronic lymphocytic leukemia (T-CLL) patient, were expanded by culture in the presence of interleukin-2 (IL-2). In contrast to the original leukemic T cells that showed a complete lack of suppressor activity, the proliferating T-CLL cells were extremely potent inhibitors of mitogen, antigen and alloantigen induced lymphoproliferative responses. Compared to the fresh T-CLL cells, the proliferating T-CLL cells showed an enhanced expression of the human T-cell leukemia/lymphoma virus (HTLV) p19 antigen and released type C virus particles into their culture supernatant. A direct involvement of the virus particles in the suppression was however unlikely, since the inhibition was found to be mediated by a soluble inhibitor in the culture supernatant of proliferating T-CLL cells. This inhibitor was very hydrophobic and was inactivated by treatment with trypsin, by heating to 56°C for 2 h and by storage at −70°C for more than 14 weeks. It could be excluded that the suppression of lymphoproliferation was due to competition for IL-2, to toxic effects, to nutrient depletion or to a shift in the kinetics of the target cell responses. Furthermore, it could not be attributed to suppressor inducer activity of the OKT4+ proliferating T-CLL cells, since normal T cells enriched for OKT4+ T cells and depleted for OKT8+ T cells were also inhibited in their proliferation. Since other hemopoietic cell lines, not of OKT4+ T lymphocyte origin, also were suppressed to proliferate, it is concluded that the proliferating T-CLL cells represent a neoplastic T-cell clone that had differentiated into suppressor effector T cells after prolonged culture in the presence of IL-2.

Enhanced expression of human T-cell leukemia/lymphoma virus in neoplastic T cells induced to proliferate by phorbol ester and interleukin-2.

Peripheral blood T cells from a patient with T-cell chronic lymphocytic leukemia (T-CLL) failed to respond to mitogenic lectins or alloantigens but could be induced to proliferate by the addition of exogenous interleukin-2 (IL-2). The T-CLL cells also proliferated in response to 12-O-tetradecanoyl phorbol-13-acetate (TPA), or to TPA in combination with phytohemagglutinin (PHA). These TPA-mediated proliferative responses were transient, and only small but significant amounts of IL-2 activity were generated. In contrast, no IL-2 activity was produced after the T-CLL cells had been stimulated with PHA only. The T-CLL cells that were induced to proliferate with PHA and exogenous IL-2 could be maintained in continuous culture by the addition of exogenous IL-2 at regular intervals. These continuously proliferating T-CLL cells failed to produce IL-2 constitutively. However, they could be induced to produce IL-2 activity by stimulation with TPA or TPA plus PHA. Irradiation of the proliferating T-CLL cells prior to incubation with TPA or TPA plus PHA resulted in a 9-fold increase in IL-2 activity, suggesting that the proliferating T-CLL cells were able to consume the IL-2 they produced. Studies on the presence of human T-cell leukemia/lymphoma virus (HTLV) in the fresh and proliferating T-CLL cells revealed that 12% of the fresh cells expressed the HTLV p19 structural core protein. HTLV p19 expression was strongly enhanced in the T-CLL cells induced to proliferate by TPA (66%) and in the continuously growing IL-2-dependent T-CLL cells (82%). In the latter culture, but not in the fresh T-CLL cells, type-C virus particles were observed. These results indicate that HTLV expression correlates with T-CLL cell proliferation but not with IL-2 production by these cells.

Existence of tartrate-resistant acid phosphatase activity in differentiated lymphoid leukemic cells.

Acid phosphatase (AcP) in neoplastic cells from various lymphoid leukemias was examined. In the cytochemical studies, tartrate-resistant AcP (T-rAcP) activity was observed in the neoplastic cells from well-differentiated lymphoid leukemias such as adult T-cell leukemia (ATL), B-cell chronic lymphocytic leukemia (B-CLL), T-cell chronic lymphocytic leukemia (T-CLL), and hairy-cell leukemia (HCL). T-rAcP activity was also detected in a small number of leukemic cells obtained from T-cell acute lymphoblastic leukemia (T-ALL), while it was not detected in the neoplastic cells from null-ALL, macroglobulinemia, and multiple myeloma (MM). In the electrophoretical studies, fraction 1 (F-1), F-3, F-3b, and F-4 were completely tartrate-sensitive, while F-2 was partially resistant and F-5 was completely resistant. T-rAcP activity (F-5) was observed in ATL cells, B-CLL cells, and HCL cells, while it was not detected in ALL cells, macroglobulinemia cells, and MM cells. The present study indicates that T-rAcP activity is observed not only in HCL cells but also in the well-differentiated lymphoid cells such as ATL cells, B-CLL and T-CLL cells except the most highly differentiated forms of B-cells of MM and macroglobulinemia.

Characterization of a Suppressor T-Cell Chronic Lymphocytic Leukemia With ADCC But Not NK Activity

AbstractA patient with T-cell chronic lymphocytic leukemia (T-CLL) is reported whose cells demonstrate in vitro suppression of normal lymphocyte mitogen stimulation. The patient, who remains in Rai's clinical stage 0 on no therapy after more than 24 mo of observation, has shown a less aggressive clinical course than is usually attributed to T-CLL. His peripheral blood lymphocytes (PBL) were characterized by functional assays as well as surface markers. Over 90% of the patient's PBL formed rosettes with sheep erythrocytes and were lysed by two T-cell-specific antisera plus complement, while less than 1% bore surface immunoglobulins, and only 3% had complement receptors. In addition, 45% of the PBL demonstrated la-like antigens, more than 50% expressed a receptor for the Fc portion of IgG(T7), and most of the sheep erythrocyte rosettes were inhibited by theophylline. The patient's cells failed to respond to several mitogens and they caused marked suppression of lymphoproliferative responses to normal PBL to phytohemagglutinin (PHA) and concanavalin A (Con-A). The patient's lymphocytes also exhibited antibody-dependent cytotoxic activity (ADCC) against antibody-coated nucleated target cells, but lacked demonstrable natural killer (NK) activity. This patient's T-CLL cells appear to represent the clonal expansion of a subset of T cells with a previously undescribed pattern of suppressor and cytotoxic activities.

Characterization of a suppressor T-cell chronic lymphocytic leukemia with ADCC but not NK activity

A patient with T-cell chronic lymphocytic leukemia (T-CLL) is reported whose cells demonstrate in vitro suppression of normal lymphocyte mitogen stimulation. The patient, who remains in Rai's clinical stage 0 on no therapy after more than 24 mo of observation, has shown a less aggressive clinical course than is usually attributed to T-CLL. His peripheral blood lymphocytes (PBL) were characterized by functional assays as well as surface markers. Over 90% of the patient's PBL formed rosettes with sheep erythrocytes and were lysed by two T-cell-specific antisera plus complement, while less than 1% bore surface immunoglobulins, and only 3% had complement receptors. In addition, 45% of the PBL demonstrated Ia-like antigens, more than 50% expressed a receptor for the Fc portion of IgG(T gamma), and most of the sheep erythrocyte rosettes were inhibited by theophylline. The patient's cells failed to respond to several mitogens and they caused marked suppression of lymphoproliferative responses to normal PBL to phytohemagglutinin (PHA) and concanavalin A (Con-A). The patient's lymphocytes also exhibited antibody-dependent cytotoxic activity (ADCC) against antibody-coated nucleated target cells, but lacked demonstrable natural killer (NK) activity. This patient's T-CLL cells appear to represent the clonal expansion of a subset of T cells with a previously undescribed pattern of suppressor and cytotoxic activities.