Anti-viral activity induced by culturing lymphocytes with tumor-derived or virus-transformed cells. Enhancement of human natural killer cell activity by interferon and antagonistic inhibition of susceptibility of target cells to lysis.

Interferon, induced in lymphocytes either with viruses or cell lines, increases severalfold the natural cytotoxicity of human lymphocytes on target cell lines. Cell separation experiments support the hypothesis that interferon enhances the activity of natural killer cells rather than generating a new population of effector cells. In mixed culture of lymphocytes and cell lines in which endogenous interferon is produced, interferon mediates an enhancement of cytotoxicity that represents up to 70-90% of the observed cytotoxicity. The effect of interferon on target cells is antagonistic to the effect on the lymphocytes: the susceptibility to cell-mediated lysis of various cells upon pretreatment with interferon is decreased and in some cases almost completely suppressed. Interferon renders target cells resistant to natural killer cells acting by an intracellular mechanism which requires RNA and protein synthesis. While normal fibroblasts are protected, virus-infected cells and most tumor cells usually are not protected by interferon. Interferon by stimulating very efficient nonspecific cytotoxic cells and by protecting at the same time normal cells from lysis, might render the natural killer cell system an inducible selective defense mechanism against tumor and virus-infected cells.

Anti-viral activity induced by culturing lymphocytes with tumor-derived or virus-transformed cells. Identification of the anti-viral activity as interferon and characterization of the human effector lymphocyte subpopulation.

A viral inhibitor(s) is released in the supernate of mixed cultures containing human or mouse lymphocytes and cells from certain lines. The inhibitor is active against a variety of unrelated viruses and is a protein that is not toxic for cells. It does not inactivate viruses directly, but inhibits viral replication through an intracellular mechanism that involves synthesis by the cells of both RNA and protein. These characteristics identify the inhibitor as an interferon. The anti-viral activity is contained in at least two molecular species, of approximately 25,000 and 45,000 daltons, respectively. In addition to the anti-viral activity, the supernates of the mixed cultures display an anti-cellular activity, the inhibition of DNA synthesis and of cell multiplication. The anti-viral and the anti-cellular activities are positively correlated in supernates from various cultures and in partially purified preparations. The human cell population responsible for interferon production is composed mainly of Fc-receptor positive, surface immunoglobulin negative, non-T-cell lymphocytes. The ability of certain cell lines to induce interferon seems to be preferentially associated with tumor origin or with in vitro transformation by certain viruses (Epstein-Barr virus, murine sarcoma virus).

A suppressor lymphokine produced by human T leukemia cell lines. Partial characterization and spectrum of activity against normal and malignant hemopoietic cells.

Human T leukemia cell lines spontaneously release into their medium a suppressor lymphokine, T leukemia-derived suppressor lymphokine (TLSL), able to inhibit proliferation, DNA synthesis, and colony formation in a variety of malignant hemopoietic cell lines, as well as in normal myelomonocytic progenitor cells from bone marrow and peripheral blood. Titration curves indicated that the inhibitory activity in the crude supernatant preparations ranged from 10(-3)-10(-9): the supernatants from CCRF/CEM, HUT-78, and MOLT-4 cell lines were the most active, those from HPB-ALL, JM, and CCRF/HSB2 displayed an intermediate activity, and the Jurkat supernatant was the least active. Target cell lines of B cell origin (Burkitt lymphomas) were more sensitive than granulocytic, monocytic, erythroid, and T cell lines. Partial purification by ammonium sulfate precipitation and column chromatography demonstrated that TLSL is a protein with an Mr of 88,000, as determined by gel filtration. A high Mr form (greater than 300,000) was produced in serum-free medium by one of the most active producer cell lines (CCRF/CEM), and appeared to be an aggregate of the 88,000 Mr form. Neither the partially purified fractions obtained nor the crude supernatant preparations displayed antiviral activity or contained interleukin 2. Unlike lymphotoxin and tumor necrosis factor, TLSL is cytostatic: maximal inhibition of proliferation was observed 4-5 d after addition of crude supernatant to the target cells, and was not accompanied by a significant loss in cell viability. The antiproliferative capacity of TLSL was manifested both in suspension and methylcellulose cultures. Treated target cells accumulated either in the G1 or in the S phase of the cell cycle. The effect of TLSL on the target cells is irreversible: even brief (1 h) incubation of sensitive cells with TLSL resulted in inhibition of proliferation measured 5 d later. Although TLSL is produced by leukemic T cell lines, this lymphokine inhibits proliferation of normal peripheral blood T cells in response to mitogens or alloantigens: T lymphocyte activation was inhibited by all of the T cell supernatants tested. In contrast, when T cell lines were used as targets, no inhibition of proliferation was detected with two exceptions: the low producer Jurkat cell line was sensitive to all the T cell-derived supernatants, and the intermediate producer CCRF/HSB2 cell line was sensitive only to the three most active supernatants, CCRF/CEM, MOLT-4, and HUT-78. The possible significance of TLSL and its relationship with other suppressor lymphokines previously described in other systems is discussed.

Reversal of acute myelogenous leukemia in humanized SCID mice using a novel adoptive transfer approach.

Advanced human malignancies cannot be permanently cured by adoptive transfer of autologous lymphokine-activated killer (LAK) cells. Moreover, administration of high doses of IL-2 to maintain LAK activity in vivo is associated with severe toxicity. In this study, we tested the anti-tumor efficacy of a uniquely potent MHC non-restricted human killer T cell clone (TALL-104) in humanized severe combined immunodeficient (SCID) mice bearing acute myelogenous leukemia (AML). We show that, in appropriate experimental conditions, TALL-104 cells could effectively reverse the aggressive growth of the myelomonocytic leukemia cell line U937 in SCID mouse tissues, leading to complete abrogation of AML. A single transfer of TALL-104 cells at the time of tumor challenge in combination with recombinant human (rh) IL-12 (1 microgram/d) prolonged significantly the life of the mice. However, eradication of leukemia, as monitored both clinically and by PCR, was achieved by repeated injection of the effectors at close intervals. Complete cure was obtained also upon transfer of lethally irradiated (non-proliferating) TALL-104 cells together with low doses of rh IL-2 (100 U/d). Most notably, of the mice that received multiple transfers of TALL-104 cells without cytokines in an advanced disease stage, 50% were clinically cured, and 50% survived significantly longer. The potential of TALL-104 cells as an effective and safe leukemia purging agent is discussed.

Suppression of interleukin 2-dependent human T cell growth in vitro by prostaglandin E (PGE) and their precursor fatty acids. Evidence for a PGE-independent mechanism of inhibition by the fatty acids.

PGE represent oxygenation products of polyunsaturated essential fatty acids and are important regulators of cell-mediated immune responses. Because oils enriched in such fatty acids reduce inflammation and tissue injury in vivo, we examined the effects of these PGE precursors on IL-2-driven growth of human T lymphocytes. Dihomogamma linoleic acid (DGLA), AA, and their metabolites (PGE1 and PGE2, respectively) strongly inhibited short- and long-term growth of IL-2-dependent T cell cultures; EPA was much less inhibitory and its product, PGE3, failed to suppress IL-2 responses. Short-term pretreatment of the cells with DGLA or AA and removal of the fatty acids before the proliferation assay resulted in a smaller reduction in [3H]TdR incorporation. PGE and fatty acids did not alter the number of high affinity IL-2 binding sites on the T cell cultures but reduced the percentage of cells expressing CD25 and HLA class II molecules. No PGE was detected in supernatants from the fatty acid-treated cultures. Moreover, indomethacin, a cyclooxygenase inhibitor, did not reverse the antiproliferative effects of the fatty acids. Together, these findings indicate that fatty acids can inhibit IL-2-driven T cell growth via a PGE-independent mechanism and might be relevant to inflammatory diseases associated with persistent T cell activation.

Treatment of experimental glioblastoma with a human major histocompatibility complex nonrestricted cytotoxic T cell line.

This study investigates a new approach to adoptive therapy of glioblastoma using as antitumor effector a potent major histocompatibility complex nonrestricted killer clone (TALL-104) established from a patient with acute T-lymphoblastic leukemia. The human glioblastoma cell line U-87 MG could be successfully engrafted in mice with severe combined immunodeficiency using the i.p., intracerebral, and s.c. routes. The latter model was elected to evaluate therapy based on its high reproducibility. Tumor growth in mice engrafted s.c. was proportionally associated with splenomegaly and leukocytosis. Multiple transfers of lethally irradiated (non-proliferating) TALL-104 cells at the tumor site resulted in about 50-70% inhibition of tumor growth as compared to untreated mice, with concomitant reduction of splenomegaly and leukocytosis. The antitumor effects were inversely proportional to the size of the tumor at initiation of therapy, 90-100% inhibition occurring in severe combined immunodeficiency mice treated from the day of U-87 MG challenge. Neither splenomegaly nor leukocytosis developed in animals in which tumor growth was completely blocked. Stimulation of TALL-104 cells with either interleukin 2 or interleukin 12 prior to irradiation and adoptive transfer increased the antitumor efficacy of the killer cells to about the same extent. The potential usefulness of irradiated TALL-104 cells in adjuvant therapy against glioblastomas and other well-localized tumors is discussed.

Antitumor efficacy of a human major histocompatibility complex nonrestricted cytotoxic T-cell line (TALL-104) in immunocompetent mice bearing syngeneic leukemia.

The human MHC nonrestricted cytotoxic T-cell line TALL-104 displays potent tumoricidal activity both in vitro and in animals bearing either spontaneous or induced tumors. In the present study, we used B6D2F1 mice engrafted with the syngeneic pre-B leukemia cell line 7OZ as a model system to investigate the mechanisms by which TALL-104 cells display antitumor activity in an immunocompetent host. In vitro studies indicated that 7OZ cells are resistant to TALL-104 cell-induced necrotic death, as measured in 51Cr release assays, but can be killed by the xenogeneic effectors via apoptotic mechanisms. Adoptive transfer experiments showed that 70% of cyclosporin A-treated mice that received multiple i.p. injections of gamma-irradiated (nonproliferating) TALL-104 cells at an early or intermediate stage of disease did not develop any clinical or molecular signs of leukemia. If the same treatment was initiated at an advanced disease stage, it doubled the survival of the animals. Importantly, 100% of the treated mice that remained disease-free in a 4-month follow-up period rejected a further challenge of high-dose 7OZ cells; these mice had developed tumor-specific Immoral and cellular responses. In another set of experiments, marrows from leukemic mice containing /= 30%. Ex vivo purging with a human lymphokine-activated killer cell preparation in the same conditions proved to be less effective. The overall data indicate the potent antileukemic effects of TALL-104 cells in vivo and provide evidence that xenogeneic effectors can induce tumor regression via a dual mechanism of direct tumoricidal activity and recruitment of endogenous antitumor immunity.

Phase I clinical trial with a human major histocompatibility complex nonrestricted cytotoxic T-cell line (TALL-104) in dogs with advanced tumors.

The human TALL-104 cell line is endowed with a uniquely potent MHC nonrestricted tumoricidal activity across several species. In view of the potential applicability of TALL-104 cells as an anticancer agent, this study was conducted to evaluate the possible toxicity and efficacy of this new cell therapy in a superior animal model with spontaneous tumors. Nineteen canine cases with advanced, refractory malignancies of various histological types were entered in the study. All dogs had failed all other available treatments and had very limited life expectancy. Cyclosporin A was administered p.o. (10 mg/kg/day) starting from the day before TALL-104 cell administration throughout the treatment to prevent rejection of the xenogeneic effectors. Lethally irradiated (40 Gy) TALL-104 cells (10(8)/kg) were administered systemically following two treatment schedules. In the first schedule, the cells were given every other day for 2 weeks in a row and then once a week for 3 additional weeks; in the second schedule, TALL-104 cells were administered daily for a total of 5 days. None of the 19 cases showed significant clinical or laboratory toxicity; in addition, none of the dogs had to be withdrawn from the study because of immediate adverse reactions to the infusions. The severe side effects usually associated with classical lymphokine-activated killer therapy in association with high doses of interleukin 2, such as "capillary leak syndrome," were absent in this study. Remarkably, TALL-104 therapy induced various degrees of antitumor effects in 7 of the 19 dogs, including 1 complete response (continuing at +13 months), three partial responses (duration of 2 months, 3 months, and continuing at +2 months), and three transient responses. Clinical responses and immunological parameters correlated well in each case. Taken together, these data indicate that systemic administration of lethally irradiated TALL-104 cells in the absence of exogenous interleukin 2 may be regarded as a safe and promising adjuvant type of treatment for advanced cancer patients.

The human leukemic T-cell line, TALL-104, is cytotoxic to human malignant brain tumors and traffics through brain tissue: implications for local adoptive immunotherapy.

Preclinical studies with the human MHC nonrestricted cytotoxic T-cell leukemic line, TALL-104, were performed in anticipation of its use in cellular immunotherapy trials for primary malignant brain tumors. In this study, we have: (a) quantitated the in vitro brain tumor cell lysis; (b) measured the cytokine secretion upon coincubation of TALL-104 cells with brain tumor cells; (c) investigated the effect of dexamethasone on brain tumor cell cytolysis by TALL-104 cells; (d) explored the effects of lethal irradiation and cryopreservation on TALL-104 cell viability and lytic efficacy; and (e) estimated the damage TALL-104 cells induce to murine normal and tumor brain cells and their trafficking patterns in both normal and tumor-bearing rat brain upon intracranial infusion. In vitro coincubation of TALL-104 cells with human brain tumor cells, explants, and cell lines resulted in significant lysis of them, but normal brain cells were spared. Lysis of tumor at 4 h was unaffected by dexamethasone or lethal irradiation. Secretion of tumor necrosis factor-alpha, tumor necrosis factor-beta, IFN-gamma, or granulocyte/macrophage-colony stimulating factor upon TALL-104 cell coincubation with brain tumor cells variably occurred without always correlating with lysis. In vivo experiments using irradiated TALL-104 cells, placed at multiple times into normal cannulated rat brain, produced focal sterile abscesses at the instillation site but no widespread allergic encephalitic reaction. Cells morphologically consistent with TALL-104 cells specifically trafficked from the site of instillation through the neuropil, occasionally into the contralateral brain, and egressed at perivascular and leptomeningeal spaces. In vivo experiments with cannulated rats bearing 9L gliosarcoma showed a preferential localization of the TALL-104 cells in tumor compared with normal brain. Taken together, these data support the concept that TALL-104 cells can be used as a novel nontoxic and efficacious paradigm for cellular immunotherapy trials in human primary malignant brain tumors.

The severe combined immunodeficient (SCID) mouse as a model for human myeloid leukemias.

Recent work has demonstrated the ability of lymphoblastic leukemias of pre-B- and T-cell origin to grow in severe combined immunodeficient (SCID) mice with a pattern reminiscent of the human clinical disease. Here, we investigated the possibility of engrafting human myeloid leukemias using both established cell lines and primary patient material. Whereas the two growth factor-independent cell lines K562 and U937 grew aggressively and induced leukemia in these animals, three other myeloid cell lines which require interleukin 3 or granulocyte-macrophage colony-stimulating factor for continuous growth in vitro failed to induce disease. Primary bone marrow and peripheral blood cells from five out of seven patients with different types of myeloid leukemias (undifferentiated, megakaryoblastic, monoblastic and chronic myelogenous leukemia in blast crisis) induced patterns of leukemic infiltration that were distinct for each leukemia subtype. The diagnosis of leukemia in SCID mice was established by microscopic detection of myeloblasts in the bone marrow, peripheral blood and, in some instances, in extramedullary sites, including the central nervous system and gonads. The karyotype and phenotype of the blasts recovered from mouse tissues were identical to those of the original patient cells. Moreover, human specific ALU sequences were amplified from the bone marrow DNA by polymerase chain reaction. Despite their ability to grow in vivo by serial transfers in SCID mice, the leukemic cells recovered from mouse tissues could not be maintained in vitro, even in the presence of recombinant cytokines. Overall, these data indicate that the SCID mouse may represent a useful animal model for human myeloid leukemias and for the development of new pharmacological and molecular approaches to therapy.

Clonal expansion of germline B-lineage acute lymphoblastic leukemia in severe combined immunodeficient mice.

CD19+ B lineage acute lymphoblastic leukemias (ALLs) with unrearranged Ig and TCR genes are designated germline B lineage ALLs. We used CDR3 PCR to determine whether pediatric germline B lineage ALLs contain minor subclones with rearranged Ig H V genes. In six of seven cases there were no PCR detectable CDR3 rearrangements. One case with a smear pattern on CDR3 PCR contained multiple unique CDR3 sequences at frequencies of 1-2 per 2,600, suggesting that polyclonal B cells were present at low frequency. To verify that the germline patterns were from leukemic cells and evaluate in vivo subclone differentiation, a germline B lineage ALL with the t(4;11) translocation was propagated in severe combined immunodeficient SCID) mice. The Ig and TCR genes in the leukemic cells recovered from mouse tissues were germline by Southern blot analysis except for single rearrangements that suggested subclone evolution at the Ig H and lambda loci in addition to the germline population. No CDR3 sequences were detected, indicating that the observed Ig H gene rearrangement most likely was a DJ joining. This study suggests that the transformed cell in germline B lineage ALL represents an early pro-B cell with limited tendency to further differentiate.

Cytokine modulation of the susceptibility of acute T-lymphoblastic leukemia cell lines to LAK activity.

We studied the regulatory effects of various cytokines on the susceptibility to lymphocyte-mediated lysis of cell lines established from patients with acute T-lymphoblastic leukemia (T-ALL). None of the cytokines tested affected the sensitivity of these targets to natural killer activity. In contrast, specific cytokines, different for each cell line, enhanced the susceptibility to lymphokine-activated killer (LAK) cells, while interferon gamma (IFN)-gamma always induced resistance. The same cytokines that increased LAK susceptibility also induced proliferative responses. The TALL-101 cell line, which responded to granulocyte-macrophage colony-stimulating factor (GM-CSF) with increased susceptibility to lysis, and to IFN-gamma with resistance, was used as a model to analyze the mechanisms underlying these changes. Cold target inhibition and conjugate formation assays both indicated that the changes in LAK susceptibility were not at the level of effector-target (E/T) binding. Furthermore, no significant changes in surface expression of adhesion molecules involved in E/T binding were induced by either GM-CSF or IFN-gamma on TALL-101 cells. Finally, N-alpha-benzyloxycarbonyl-L-lysine thiobenzyl-esterase assays demonstrated no differences in the ability of these cytokines to trigger the secretion of cytolysins in the bound effectors compared to unstimulated cells. Taken together, these results suggest that the cytokine-modulated susceptibility to lysis of these T-ALL lines might occur at a post-binding stage with mechanisms involving an altered responsiveness to lytic factors.

Regulation of SRC-family protein tyrosine kinases by interleukins, IL-2, and IL-3.

Unlike many other growth factor receptors, the known subunits of the receptors for the Interleukins IL-2 and IL-3 lack intrinsic tyrosine kinase activity, and yet increases in the phosphorylation of proteins on tyrosines is a rapid event in hematolymphoid cells following stimulation with these lymphokines. Here we show that IL-2 and IL-3 regulate the activity of specific members of the SRC-family of non-receptor protein tyrosine kinases (PTKs). In IL-2-dependent T-cell lines, IL-2 induced rapid and transient increases in the activity of the p56-LCK kinase without influencing the activities of other SRC-like PTKs (p59-FYN, p62-YES) in these T-lymphocytes. In contrast to IL-2's effects on p56-LCK in T-cells, studies of an IL-2-responsive cell line of the B-cell lineage that lacks p56-LCK revealed that IL-2 specifically regulates the activity of the p53/56-LYN kinase. Thus, some flexibility exists in the ability of various SRC-like PTKs to functionally couple to IL-2 signalling pathways. In several IL-3-dependent myeloid-committed leukemic cell lines, IL-3 was found to specifically regulate the activity of the p53/56-LYN kinase without affecting the activities of other SRC-like PTKs (p59/64-HCK, p59-FYN, p62-YES) in these hematopoietic cells. This finding that p53/56-LYN can be regulated by both IL-2 in B-lineage cells and IL-3 in myeloid-committed cells demonstrates that the same SRC-family PTK can participate in signal transduction events mediated via two independent receptor systems. Taken together, our findings imply that the specific combinations of lymphokine receptors and SRC-like PTKs available for coupling with those receptors are coordinately controlled during the differentiation of hematopoietic cells.

Human stem cell factor (c-kit ligand) induces an autocrine loop of growth in a GM-CSF-dependent megakaryocytic leukemia cell line.

The M07e megakaryoblastic leukemia cell line is strictly dependent on either interleukin 3 (IL-3) or granulocyte-macrophage colony-stimulating factor (GM-CSF) for continuous growth. This study shows that recombinant human stem-cell factor (rhSCF) can completely replace these lymphokines in supporting the continued propagation of M07e cells mostly by eliciting GM-CSF secretion in this target. In fact, in short-term proliferation assays the stimulatory activity of SCF is blocked about 75% by a GM-CSF-specific serum. In addition, we could detect GM-CSF expression by SCF-stimulated M07e cells, both at the protein and mRNA levels. In contrast, SCF does not induce transcripts for any other cytokine to which M07e cells are responsive, including IL-2, IL-3, IL-4, and IL-6. Overall, these data show that the ability of SCF to support the growth of this megakaryocytic cell line is mediated mostly by the induction of an autocrine loop of activation involving GM-CSF production. The finding that SCF can stimulate GM-CSF secretion also in an IL-2-dependent T-lymphoblastic leukemia cell line indicates that SCF can act on cells of both myeloid and lymphoid lineages, and that the ability to induce cytokines in target cells represents an important aspect of its mechanism of action.

Pediatric leukemia/lymphoma with t(8;14)(q24;q11).

A variety of chromosomal translocations occur in pediatric T-cell acute lymphoblastic leukemia (T-ALL) in which a cellular oncogene or growth-related gene is translocated to the alpha/delta locus of the T-cell receptor gene. The t(8;14)(q24;q11) has been described at the cytogenetic and molecular level, but the disease associated with this translocation has not been defined clinically. Fifteen pediatric cases of leukemia/lymphoma with a t(8;14)(q24;q11) chromosomal translocation were collected from previous publications and institutional records. The estimated prevalence of this abnormality among all cases of ALL was 1%. The t(8;14)(q24;q11) disease was characterized by male predominance (10/15), a median age of 5.5 years (range 1.8-17 years), high white blood cell count (median 95 x 10(9)/l), central nervous system infiltration (4/11), bulky extramedullary leukemia (10/11), and T-cell immunophenotype (12/15). The median event-free survival was 4 months, and the median survival, 11 months. Seven cell lines with t(8;14)(q24;q11) were established from six of the cases; four were T-lymphoblastic, one was T-lymphoblastic, but expressed myeloid-related antigens, and two were predominantly myeloid. t(8;14)(q24;q11) leukemia/lymphoma and other ALLs involving 13(q11) have in common a high tumor burden, early spread to extramedullary sites, a propensity to form T-lymphoblastic or T-myeloid cell lines and, usually, an aggressive clinical course.

Adjuvant treatment of canine osteosarcoma with the human cytotoxic T-cell line TALL-104.

The human cytotoxic T-cell line TALL-104 has been used successfully to treat cancer in experimental mouse models with implanted tumors and in dogs with spontaneously occurring malignancies. This study investigated the efficacy of TALL-104 cells given in an adjuvant setting to dogs with appendicular osteosarcoma after surgery and chemotherapy. Of the 23 dogs enrolled in the study, 20 had undergone amputation of the affected limb, and 3 had undergone limb salvage surgery. After surgery, all dogs but one received cisplatin (CDDP) chemotherapy (60 mg/m2 i.v. every 21 days x 1-4 cycles). Four dogs also received one to six cycles of CDDP before limb amputation. After CDDP therapy, dogs without overt metastasis received gamma-irradiated (40 Gy) TALL-104 cells systemically (10(8)/kg) for 5 consecutive days, followed by 2-day monthly boosts (at the same dose) for a total of 9 months. Of the 23 dogs treated, 9 survive disease-free at 12.1-29.5 months after surgery, 11 died of metastatic disease between 5 and 21.5 months, 1 experienced a relapse in the lung 9.5 months after surgery but is still alive without further treatment at 13 months, 1 developed severe discopathy at 4 months after surgery, and 1 developed progressive neuropathy at 5.9 months after surgery. The overall median survival time is 11.5 months, and the median disease-free interval is 9.8 months. Our cell therapy results compare favorably with historical median survival times (up to 9 months) and disease-free intervals (up to 7.5 months) of dogs with osteosarcoma receiving standard therapy (surgery and chemotherapy) and support the effectiveness of adjuvant TALL-104 cell administration in preventing or delaying disease recurrence in these dogs.

Successful treatment of canine malignant histiocytosis with the human major histocompatibility complex nonrestricted cytotoxic T-cell line TALL-104.

The human MHC nonrestricted cytotoxic T-cell line TALL-104 exerts potent antitumor effects in animal models with both induced and spontaneous cancers. The present report documents the ability of systemically delivered TALL-104 cells to induce durable clinical remissions in four of four dogs with malignant histiocytosis (MH). The animals received multiple i.v. injections of lethally irradiated (40 Gy) TALL-104 cells at a dose of 10(8) cells/kg, with (two dogs) or without (two dogs) cyclosporin A, followed by monthly boosts. No significant clinical or laboratory toxicities developed during cell therapy; interestingly, a strong correlation was found between the dogs' clinical and immunological responses. One dog with advanced disease (intrathoracic involvement) refractory to chemotherapy achieved a complete remission (CR) within 2 months of the first TALL-104 cell infusion. This dog died 14 months later of unrelated causes: histological analysis of its organs postmortem revealed no evidence of neoplasia, thus confirming the achievement of CR also at the pathological level. The other three dogs with MH that at diagnosis had multiple s.c. and cutaneous lesions and lymphadenopathy, but no visceral involvement, were treated with TALL-104 cells as single agent (no chemotherapy was administered). Two of these dogs achieved a CR soon after cell therapy, and the third dog had two long-lasting partial responses; CR in this dog was later achieved by combined administration of chemotherapy and cell therapy. None of the three dogs that received cell therapy at diagnosis developed visceral disease in the approximately 9-22 months of follow-up. The clinical responses experienced by all four MH cases to TALL-104 cell therapy suggest the high responsiveness of this canine tumor to these xenogeneic effectors and their therapeutic potential even in the most aggressive forms of the disease.

Cell therapy of a highly invasive human breast carcinoma implanted in immunodeficient (SCID) mice.

Although enormous progress has been made in the detection and treatment of localized (nonmetastatic) breast cancer, there has been relatively moderate progress toward the effective treatment of advanced disease. This study investigates the antitumor efficacy of a potent MHC nonrestricted cytotoxic human T cell line (TALL-104) upon transfer into a clinically relevant mouse model of metastatic breast cancer. Fragments from a surgical specimen of a patient with infiltrating ductal carcinoma were implanted s.c. in the flank region of severe combined immunodeficient (SCID) mice. One hundred % of the animals developed a local tumor mass that metastasized to subaxillary and inguinal lymph nodes, bones, lungs, liver, kidneys, ovaries, and brain, very closely mimicking the human disease. Multiple i.p. transfers of gamma-irradiated (nonproliferating) TALL-104 cells into mice bearing low tumor burden (the primary tumor mass weighed only 150 mg) completely arrested local tumor growth and prevented systemic spread into local lymph nodes and distant organs. Remarkably, cell therapy administered in an advanced disease stage (when the tumor weighed 2 g) induced a significant or total regression of established metastasis with no obvious effects on the primary tumor mass. Profound antitumor effects against both local and systemic disease were instead seen in mice that received cell therapy after surgical excision of the primary tumor. The implications of these data in adjuvant breast cancer therapy are discussed.

Phase I trial of TALL-104 cells in patients with refractory metastatic breast cancer.

The human cytotoxic T-cell line TALL-104 displays antitumor effects in animals with implanted and spontaneous malignancies. A Phase I trial was conducted to determine toxicity of TALL-104 cell therapy in women with metastatic refractory breast cancer. Fifteen patients with metastatic infiltrating ductal (n = 12), lobular (n = 2), or medullary (n = 1) carcinoma received escalating doses of lethally irradiated TALL-104 cells (three patients/group received 10(6), 3 x 10(6), 10(7), 3 x 10(7), and 10(8) cells/kg) for 5 consecutive days (induction course). Patients without progressive disease received monthly maintenance 2-day infusions at the same dose level. Mild grade I/II toxicity developed in 11 patients regardless of cell dose. One grade IV toxicity consequent to hepatic tumor necrosis occurred in a patient given 10(8) cells/kg, 3 weeks after the induction course. Nine patients progressed within 1 month from induction, and five patients had stable disease for 2-6 months. One patient (at 3 x 10(7)/kg) had improvement of liver metastases and ascites, and a second patient (at 10(6)/kg) experienced a dramatic relief in bone pain. Increases in blood natural killer cell activity and levels of IFN-gamma, interleukin-10, and activation markers (soluble interleukin-2 receptor and soluble intercellular adhesion molecule-1) were often seen. Only one patient developed anti-HLA class I antibody responses against TALL-104 cells; specific CTL activity developed in three patients during induction and in four patients during the maintenance boosts. In conclusion, TALL-104 cells were well tolerated by patients with metastatic breast cancer at the doses and regimen tested. The clinical responses observed in this preliminary trial demonstrate that further investigation of TALL-104 cell therapy is warranted.

Effects of fatty acids on proliferation and activation of human synovial compartment lymphocytes.

The object of this study was to determine the effects of eicosanoid precursor fatty acids on activation and proliferation of T lymphocytes from synovial fluid and synovial tissue of rheumatoid arthritis patients. Proliferation was determined by direct cell counts; phenotypic characterization of surfaces molecules was by cytofluorometric analysis. Dihomogammalinolenic acid, arachidonic acid, and eicosapentaenoic acid suppressed proliferation of interleukin-2-dependent lymphocytes by as much as 80%; cell viability was not altered by fatty acids. Administration of particular fatty acids may prove to be a useful therapeutic intervention in rheumatoid arthritis patients because of their ability to suppress activation and proliferation of synovial compartment T lymphocytes.