ALBERT

Description: Interleukin-11 (IL-11) is a pleiotropic cytokine with effects on many different targets. Within the hematopoietic system, the effects of IL- 11 are largely manifest only through combination with other cytokines, including IL-3 and Steel factor (SF). In the present study, we addressed the question of IL-11 responsiveness within the different types of human leukemic cells, as well as the mechanism of action of IL- 11 at the cellular level. Analysis of a panel of samples from different patients with acute myeloblastic leukemia (AML) and myeloid leukemic cell lines indicated that IL-11 alone was ineffective in supporting myeloid leukemic cell growth but frequently enhanced growth supported by IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), or SF. In contrast, three acute pre-B lymphocytic leukemia (pre-B-ALL) and two acute T lymphocytic leukemia (T-ALL) lines failed to respond to IL- 11 alone or when combined with other cytokines. The growth enhancement of IL-11 among the AML patient samples was dose dependent and remarkably constant with half-efficient concentrations in the range of 0.3 to 0.4 ng/mL. The thymidine suicide studies with the patient samples revealed that 40% to 50% of the blast cells were in S-phase when exposed for 16 hours to IL-3 and this level was increased to 70% to 90% in response to either IL-11 or IL-6. Our data suggest that the latter two interleukins act synergistically with the direct mitogenic factor, IL-3, in triggering AML blast-cell proliferation. Detailed analysis with several patient samples further revealed that SF and IL- 11 both enhance IL-3-supported clonogenic growth of AML blasts and the combination of all three growth factors yields optimal growth. In contrast, IL-6 does not further enhance the effect of IL-11. These results indicate that SF and IL-11 enhance IL-3-dependent clonogenic growth through two distinct pathways, whereas IL-6 and IL-11 may trigger the same pathway.

Description: Bone marrow (BM) cells from a child with an immature (CD3-) acute T lymphoblastic leukemia (T-ALL) bearing no chromosomal abnormalities failed to grow in long-term culture in the presence or absence of recombinant human (rh) growth factors but could be engrafted in severe combined immunodeficient (SCID) mice and induced leukemia. The leukemic cells recovered from the animal tissues could be adapted to grow in vitro in the presence of rh interleukin-2 (IL-2) and give rise to a growth factor-dependent cell line designated TALL-107. This cell line expresses T-cell-specific mature markers (CD2, CD3/T-cell receptor [TCR] alpha beta, CD8, CD56), and its growth can be inhibited by IL-4 of all the cytokines tested. Similar to the original leukemic blasts, TALL-107 cells are clonal, have rearranged TCR-beta, gamma, and delta loci, and a normal 46 XY karyotype. However, unlike the patient's BM cells, the TALL-107 cell line displays potent tumoricidal activity that is not major histocompatibility complex restricted. The magnitude of mRNA expression of perforin and serine esterases and of lytic activity depends on the doses of IL-2 added. TALL-107 cells can also be triggered by CD3- and CD2-specific monoclonal antibodies (MoAbs) to mediate reverse tumor cell lysis. In addition, this cell line produces high levels of interferon gamma and tumor necrosis factor alpha on stimulation with anti-CD3 and/or anti-CD2 MoAb both in the presence or absence of IL-2. The overall data indicate that the SCID mouse is able to support the functional maturation and expansion of a cytotoxic T- cell subset from some types of T-ALL.

Description: Bone marrow (BM) cells from a child with an immature (CD3-) acute T lymphoblastic leukemia (T-ALL) bearing no chromosomal abnormalities failed to grow in long-term culture in the presence or absence of recombinant human (rh) growth factors but could be engrafted in severe combined immunodeficient (SCID) mice and induced leukemia. The leukemic cells recovered from the animal tissues could be adapted to grow in vitro in the presence of rh interleukin-2 (IL-2) and give rise to a growth factor-dependent cell line designated TALL-107. This cell line expresses T-cell-specific mature markers (CD2, CD3/T-cell receptor [TCR] alpha beta, CD8, CD56), and its growth can be inhibited by IL-4 of all the cytokines tested. Similar to the original leukemic blasts, TALL-107 cells are clonal, have rearranged TCR-beta, gamma, and delta loci, and a normal 46 XY karyotype. However, unlike the patient's BM cells, the TALL-107 cell line displays potent tumoricidal activity that is not major histocompatibility complex restricted. The magnitude of mRNA expression of perforin and serine esterases and of lytic activity depends on the doses of IL-2 added. TALL-107 cells can also be triggered by CD3- and CD2-specific monoclonal antibodies (MoAbs) to mediate reverse tumor cell lysis. In addition, this cell line produces high levels of interferon gamma and tumor necrosis factor alpha on stimulation with anti-CD3 and/or anti-CD2 MoAb both in the presence or absence of IL-2. The overall data indicate that the SCID mouse is able to support the functional maturation and expansion of a cytotoxic T- cell subset from some types of T-ALL.

Description: The capacity to generate lymphokine-activated killer (LAK) cells and the susceptibility of the neoplastic cells to both allogeneic and autologous LAK effectors were studied in B and T chronic lymphoproliferative disorders. While in B-cell chronic lymphocytic leukemia (B-CLL) the depressed natural killer function could be restored after a 7-day incubation with recombinant interleukin (IL-2), B-CLL mononuclear cells showed a reduced LAK activity compared with normal LAK cells. Furthermore, in all but 1 of the 20 B-CLL samples tested the leukemic cells were totally resistant to autologous LAK effectors. In most cases the leukemic cells were also resistant to normal allogeneic LAK cells. Competition experiments demonstrated that the patients' LAK cells, as well as normal LAK effectors, were capable of recognizing B-CLL cells, pointing, therefore, to a postbinding cytolytic defect. In hairy cell leukemia (HCL) an overall reduced LAK activity against allogeneic targets was documented, but, at variance from B-CLL, hairy cells were often susceptible to the lytic effect of normal LAK cells, and in half of the cases tested the neoplastic population was also sensitive in an autologous system. Similarly to B- CLL, in the great majority of T chronic lymphoproliferative disorders studied, the pathologic cells were resistant to normal and autologous LAK effectors and a defective LAK generation was found. These results demonstrate that in most B and T chronic leukemias the LAK function is defective and, when inducible, does not appear directed against the leukemic population. The possibility of exploiting an immunotherapeutic approach with IL-2/LAK cells in the management of chronic lymphoproliferative disorders does not gain support by these findings.

Description: The aim of this study was to analyze the homing and progression patterns of childhood acute lymphoblastic leukemias (ALL) in mice with severe combined immunodeficiency (SCID). Upon intraperitoneal (IP) transfer, cells from relapse samples of three children with T-lineage ALL spread hematogenously and infiltrated the non-lymphoid and/or lymphoid organs with a pattern reminiscent of the human clinical disease. These mice either died or were killed in extremis at a mean of 9 weeks. Moreover, cell lines established in vitro from two of these samples manifested identical homing and progression in the SCID mouse as compared with the original patients' cells. Thus, long-term culture of the primary leukemic T cells did not alter their invasive potential and migration pattern. When engrafted IP, three cell lines established from pre-B-ALL cases displayed primarily a lymphatic spread with induction of local tumor masses and kidney/liver nodules. Mice were killed at 11 to 13 weeks, but had not developed imminently fatal leukemia. However, when transferred intravenously, one pre-B ALL cell line was able to spread hematogenously and to infiltrate both lymphoid and non-lymphoid tissues. Overall, these data demonstrate that the SCID mouse provides an efficient and reproducible model to study the pathogenesis of childhood ALL, and may be a suitable system for evaluating therapy.

Description: Cells from 10 cases of childhood acute T-lymphoblastic leukemia (T-ALL) were cultured in the presence of recombinant human interleukins (rhIL) or colony-stimulating factors (CSF) to analyze their growth factor requirements and differentiative potential. Although cells from most leukemic samples displayed a short-term proliferative response to several hematopoietic growth factors, only the ones featuring chromosomal translocations could be established as permanent cell lines. Two cell lines could be initiated only in the presence of IL-3 (TALL-103 and TALL-106), one in granulocyte-macrophage CSF (GM-CSF) (TALL-101), and one in IL-2 (TALL-104); only one cell line (TALL-105) was originated in the absence of growth factors. The TALL-101 and TALL- 103 cell lines, derived from very immature T-ALL cases, underwent growth factor-dependent phenotypic conversion (lymphoid to myeloid). However, the T-cell receptor rearrangement and karyotype of the original leukemic clones were retained. In contrast, the TALL-104, - 105, and -106 cell lines which originated from more mature T-ALL cases, maintained a T-lymphoblastic phenotype regardless of the growth factors in which they were expanded. These data demonstrate in vitro the aggressive nature of T-ALL cases bearing chromosomal abnormalities, and indicate that the lineage commitment of the malignant clone depends on its stage of maturation in T-cell ontogeny.

Description: The capacity to generate lymphokine-activated killer (LAK) cells and the susceptibility of the neoplastic cells to both allogeneic and autologous LAK effectors were studied in B and T chronic lymphoproliferative disorders. While in B-cell chronic lymphocytic leukemia (B-CLL) the depressed natural killer function could be restored after a 7-day incubation with recombinant interleukin (IL-2), B-CLL mononuclear cells showed a reduced LAK activity compared with normal LAK cells. Furthermore, in all but 1 of the 20 B-CLL samples tested the leukemic cells were totally resistant to autologous LAK effectors. In most cases the leukemic cells were also resistant to normal allogeneic LAK cells. Competition experiments demonstrated that the patients' LAK cells, as well as normal LAK effectors, were capable of recognizing B-CLL cells, pointing, therefore, to a postbinding cytolytic defect. In hairy cell leukemia (HCL) an overall reduced LAK activity against allogeneic targets was documented, but, at variance from B-CLL, hairy cells were often susceptible to the lytic effect of normal LAK cells, and in half of the cases tested the neoplastic population was also sensitive in an autologous system. Similarly to B- CLL, in the great majority of T chronic lymphoproliferative disorders studied, the pathologic cells were resistant to normal and autologous LAK effectors and a defective LAK generation was found. These results demonstrate that in most B and T chronic leukemias the LAK function is defective and, when inducible, does not appear directed against the leukemic population. The possibility of exploiting an immunotherapeutic approach with IL-2/LAK cells in the management of chronic lymphoproliferative disorders does not gain support by these findings.

Description: In 26 myeloid and lymphoid acute leukemia patients at presentation the capacity to generate interleukin-2 (IL-2)-induced lymphokine-activated killer (LAK) cells effective against the natural killer (NK)-resistant Raji cell line, as well as the susceptibility of the blasts to normal peripheral blood (PB) LAK cells and to autologous LAK effectors was analyzed. The overall PB LAK activity against Raji cells was significantly lower in acute leukemia patients compared with normal controls (mean, 1,473 +/- 971 SD LU/10(8) LAK effectors v 3,340 +/- 1,862; P less than .001). The sensitivity of the blasts to autologous LAK cells was also significantly lower than to normal LAK effectors (517 +/- 593 LU/10(8) LAK effectors v 1,304 +/- 1,066; P less than .01). When the data were analyzed independently, four patterns of behavior could be recognized. The relatively largest group (9 of 26) included patients in whom effective LAK cells could be generated against the Raji line, but in whom the blasts were resistant to autologous PB-LAK effectors while being susceptible to normal LAK cells (defective specific LAK activity). In 5 of 26 cases, an incapacity to generate LAK activity against both allogeneic and autologous target cells was observed (defective LAK generation). In six further cases, the blasts were resistant to both allogeneic and autologous LAK populations, though the latter were effective against the Raji line (resistant blasts). The same defects could also be shown with bone marrow-derived LAK cells. Only in six cases did the leukemic blasts appear susceptible to autologous and allogeneic LAK cells. In four patients the analysis could be repeated at remission, and in three a restoration of the LAK function against the primary blasts was recorded. In the 10 cases studied at relapse, the blasts were resistant to autologous LAK effectors in nine and to normal LAK in seven. These data demonstrate that in most acute leukemia patients with active disease, a defect of the LAK machinery, either a deficient generation of LAK cells or the resistance of the blasts to LAK effectors, may be documented, pointing therefore to a possible contributory role of the LAK system in the control of leukemic cell growth. In view of the frequent normalization of the autologous LAK activity at the time of remission, immunotherapy with IL-2/LAK cells should be primarily aimed to patients with minimal residual disease.