Simultaneous Fluorescent Identification of Odontoblasts and Ameloblasts.

The tooth is mainly composed of dentin and enamel. Identification of dentin-producing odontoblasts and enamel-producing ameloblasts using reporter techniques is useful to study tooth development and regeneration with tissue engineering. Ameloblasts express Amelogenin, Ameloblastin, Enamelin, and Amelotin, whereas odontoblasts express Dentin sialophosphoprotein (Dspp) and Dentin matrix protein1 (Dmp1). Although there are several transgenic lines using promoter elements or bacterial artificial chromosomes (BACs) to label odontoblasts and ameloblasts, there is a possibility that the expression patterns vary from the endogenous genes. Here, we established 2 lines of mice where tdTomato was knocked into the second exon of X-chromosomal Amelogenin (Amelx), and green fluorescent protein (GFP) was knocked into the second exon of Dspp. tdTomato and GFP were highly expressed on secretory ameloblasts and secretory and fully differentiated odontoblasts, respectively. In addition, DSPP and AMELX were not produced in the dentin matrix and enamel matrix of DsppGFP/GFP and AmelxtdTomato male mice (as representative of AmelxtdTomato/Y hemizygous male mice), respectively. Moreover, micro-computed tomography analysis of AmelxtdTomato male mice revealed a notable reduction in enamel volume but increased dentin mineral density. DsppGFP/GFP mice had reduced dentin mineral density. To identify odontoblasts and ameloblasts from developing tooth, we examined the expression of mesenchymal cell surface molecules CD90, CD166 and epithelial cell surface molecules CD49f, Epcam1 with fluorescence on odontoblasts and ameloblasts in these mice. We found that GFP+ odontoblasts and tdTomato+ ameloblasts in tooth germ from 0.5-d-old DsppGFP/+ mice and AmelxtdTomato male mice were enriched in CD45-/Ter119-/Epcam1-/CD90+/Integrin α4+cell fractions and CD45-/Ter119-/Epcam1+/CD49f+/CD147+ cell fractions, respectively. By using antibodies against mesenchymal and epithelial cell surface molecules and fluorescence, we can easily distinguish odontoblasts from ameloblasts and isolate each cell for further studies. These mice would serve as useful models for tooth development and regeneration as well as provide concurrent observation for the differentiation processes of odontoblasts and ameloblasts in vivo and in vitro.

Altered transcription of the c-abl oncogene in K-562 and other chronic myelogenous leukemia cells.

Expression of the cellular abl (c- abl ) oncogene was studied in K-562 and other chronic myelogenous leukemia (CML) cells and cell lines by means of Northern blot hybridization. In contrast to non-CML cells, which contained 7.4- and 6.8-kilobase abl -related transcripts, the CML cells contained a predominant and novel 8.2-kilobase abl -related RNA. In addition, the levels of abl -related message were up to eight times higher in CML cell lines from patients at the blast crisis stage of the disease compared with CML cells obtained during the chronic phase and with non-CML cells.

A new subtype of human T-cell leukemia virus (HTLV-II) associated with a T-cell variant of hairy cell leukemia.

Human T-cell leukemia virus (HTLV) is a human type-C RNA tumor virus (retrovirus) previously identified in and isolated from several patients with T-cell leukemias or lymphomas. The known virus isolates from the United States and Japan are closely related and are found in adults with an acute malignancy of mature T cells. A related retrovirus has been found in a patient (Mo) with a somewhat different disease (a T-cell variant of relatively benign hairy cell leukemia). Serum from Mo contains antibodies to the major internal core protein (p24) of HTLV. A T-cell line established from the spleen of Mo expresses HTLV antigens. However, HTLV from Mo is significantly different from all previous HTLV isolates in immunological cross-reactivity tests of p24. The usual prototype HTLV isolate is represented as HTLV-I, and the HTLV from Mo is represented as HTLV-II. Individual members of each subgroup may then be identified by subscript initials of the patient [for example, HTLV-I(CR), HTLV-I(MB), and HTLV-II(Mo)].

An Asian variant of intravascular lymphoma: unique clinical and pathological manifestation in the gallbladder.

We here present a rare case of intravascular lymphoma (IVL) in a Japanese man. 4 months after cholecystectomy due to cholecystitis, a diagnosis of intravascular lymphoma (IVL) was strongly suspected. Lymphoma cells were diffusely observed in the bone marrow parenchyma, but were absent in the vascular spaces. The patient died of respiratory failure and at autopsy a small number of lymphoma cells in the extravascular parenchyma of the adrenal gland and bone marrow were seen. Serial sections of the surgically resected gallbladder retrospectively confirmed the diagnosis of IVL. In addition, congestion and edema were observed in the connective tissue layer. It is possible that edema or ischemia in the gallbladder wall or at other anatomic sites due to the circulation disturbance induced by the intravascular obstruction of lymphoma cells may have caused the initial symptoms. In conclusion, clinicians and pathologists should keep in mind that the gallbladder may be initially involved in IVL.

Bridging necrosis and reticulin bridging fibrosis induced by intrahepatic involvement of acute biphenotypic leukemia.

A 47-year-old Japanese woman was diagnosed as having acute biphenotypic leukemia with association of t(9;22)(q34;q11). Cholestatic liver dysfunction arose, and she died of cachexia and intracranial hemorrhage. Autopsy showed unusual hepatic fibrosis. In the liver, bridging infiltration, bridging necrosis and bridging fibrosis by leukemic cells were seen. It seemed that the degree of fibrosis was associated with the number of aggregates of infiltrating leukemic cells. The fibrotic foci were predominantly composed of reticulin and collagen fibers, and distortion of the lobules was observed. Immunohistochemically, dense bundles of alpha-smooth muscle actin (ASMA)-positive stromal cells, namely activated hepatic stellate cells (HSCs), were observed in the immature fibrotic foci as well as along the sinusoids densely infiltrated by leukemic cells. No cells positive for TGF-beta1 or PDGF-BB were identified. In conclusion, extensive intrahepatic involvement by neoplastic cells in adult acute biphenotypic leukemia may cause the unusual "disorganized" hepatic fibrosis.

Comparison of the stimulating capacity of human leukemia T-cell, null cell, and B-cell lines in mixed lymphoma culture.

One-way mixed lymphocyte reactions between lymphocytes from normal human donors and mitomycin C-treated cells from human leukemia T-cell, null cell, and B-cell lines were investigated. An Epstein-Barr virus (EBV)-negative Japanese Burkitt's lymphoma line and two EBV-positive normal lymphoid cell lines were studied in parallei. Normal lymphocytes were stimulated significantly by the cultured null cells and B-cells, but only slightly by the cultured T-cells. The stimulatory capacity of these two leukemia cell lines was approximately equal to that of the lymphoma and normal B-cell lines. The results suggest that not only leukemia B-cells but also leukemia null cells have stimulatory determinants in mixed lymphocyte culture.

Establishment of an Epstein-Barr virus-determined nuclear antigen-negative human B-cell line from acute lymphoblastic leukemia.

A human B-cell line designated as BALL-1 was established from the peripheral blood of a patient with acute lymphoblastic leukemia (ALL). Neither Epstein-Barr virus (EBV) particles nor EBV-determined nuclear antigen (EBNA) was detectable. The morphologic and growth characteristics were clearly distinct from those of numerous EBV-positive lymphoblastoid cell lines previously reported. BALL-1 cells probably originated from the donor's leukemia cells as judged from their cytogenetic, morphologic, and surface features. The BALL-1 line was the first EBNA-negative B-cell line established from ALL.

Necessity of bile for and lack of inhibitory effect of retinoid on development of forestomach papillomas in nontreated mutant mice of the W/Wv genotype.

The pathogenesis of papillomas which developed spontaneously in the forestomach of WB X C57BL/6 F1-W/Wv mutant mice was investigated. The thickness of the forestomach epithelium was used as a quantitative index for development of papillomas. From the 15th day after birth, the forestomach epithelium of the W/Wv mice was significantly thicker than that of the congenic +/+ mice. Administration of aromatic retinoic acid analog (ethyl all-trans-9-(4-methoxy-2,3,6-trimethylphenyl)-3,7-dimethyl-3,7-dimethyl-2,4,6,8 -nonatetraenoate) did not suppress development of papillomas. Since papillomas did not appear in the stomach which was removed from the W/Wv embryos and grafted to the s.c. space produced in the back of the adult mice and since a considerable amount of bile reflux preceded development of papillomas, bile reflux may be a cause of papillomas in W/Wv mice.

Secretion of parathyroid hormone-like activity from human T-cell lymphotropic virus type I-infected lymphocytes.

Because many patients with adult T-cell leukemia/lymphoma (ATLL) develop hypercalcemia with similar characteristics to those of humoral hypercalcemia of malignancy (HHM) (Arch. Intern. Med., 148: 921-925, 1988), we investigated if ATLL cells produce parathyroid hormone (PTH)-like activity. Conditioned media from cultures of human T-cell lymphotropic virus type I-infected cell line (MT-2) as well as peripheral lymphocytes from a hypercalcemic ATLL patient stimulated cyclic AMP production in osteoblast-like rat osteogenic sarcoma cells (UMR 106) and bone resportion in organ cultures of fetal mouse calvaria. Furthermore, the stimulation of cyclic AMP production by conditioned medium of MT-2 cells was inhibited by human PTH(3-34), indicating that MT-2 cells secrete PTH-like activity. The PTH-like activity from MT-2 cells was chromatographically indistinguishable from the one extracted from a solid tumor causing HHM. The present results along with our previous observation that MT-2 cells constitutively express mRNA for PTH-related protein (Biochem. Biophys. Res. Commun., 154: 1182-1188, 1988) demonstrate that a PTH-like activity is synthesized and secreted by these cells, and are consistent with the hypothesis that elaboration of PTH-like activity by ATLL cells may be the mechanism by which hypercalcemia develops in ATLL patients as well as in solid cancer patients with HHM. However, these results do not rule out the possibility that other factors such as interleukin 1 are also involved and may act in concert with PTH-like activity in the development of hypercalcemia in ATLL.

Novel t(15;19)(q15;p13) chromosome abnormality in a thymic carcinoma.

A 22-year-old female with a thymic carcinoma is reported. The tumor was refractory to both chemotherapy and irradiation. The patient died with an aggressive clinical course. Cytogenetic study showed that the tumor cells had a chromosome translocation, t(15;19)(q15;p13), which was not identified previously in human cancer.

Dimorphism of sister chromatid exchange in Bloom's syndrome B- and T-cell lines transformed with Epstein-Barr and adult T-cell leukemia viruses.

The present study describes the establishment of both B- and T-cell lines from the peripheral blood cells of two Bloom's syndrome (BS) patients and one healthy female by using Epstein-Barr (EBV) and adult T-cell leukemia viruses (ATLV). The cell lines from normal and BS subjects exhibited cell surface markers compatible with B- and T-cell origin; in addition, the BS B- and T-cell lines retained the original cytogenetic characteristics of the syndrome. Even though phytohemagglutinin-stimulated BS lymphocytes from the two BS patients studied all showed high levels of sister chromatid exchange (SCE), the established BS B-lines with EBV yielded two separate lines each, i.e., one with increased SCE and another with normal levels of SCE; also, one of the BS T-lines retained high SCE levels in 100% of the cells, whereas the other BS T-line contained two populations, one with high SCE (70%) and the other with normal SCE levels (30%), at a relatively constant frequency over a period of 6 months. Neither EBV nor ATLV caused a significant increase in chromosome instability in the established lines compared to fresh lymphocytes. Reinfection of the BS B- and T-cell lines with EBV or ATLV did not alter the SCE or karyotypes. These results strongly suggest that BS patients have two populations in vivo, one with high and another with normal levels of SCE, at least in the lymphoid cell system.

19-nor-26,27-bishomo-vitamin D3 analogs: a unique class of potent inhibitors of proliferation of prostate, breast, and hematopoietic cancer cells.

Vitamin D3 [1,25-dihydroxyvitamin-D3 (1,25(OH)2D3)] modulates the proliferation and differentiation of many cell types. Analogs of 1,25(OH)2D3 that have greater potency may become adjuvant therapy for breast and prostate cancers, myelodysplastic syndrome, acute myelogenous leukemia in remission and other cell types, especially in the setting of low disease burden. A new class of analogs of 1,25(OH)2D3 has been synthesized that has a novel 19-nor motif, as well as incorporating many structural elements previously shown to increase potency. These analogs were examined for their effects on prostate cancer cell lines (PC-3, LNCaP, and DU 145), a human breast cell line (MCF-7), and an acute myeloid leukemia cell line (HL-60). Dose-response clonogenic studies showed that each of these analogs had more potent antiproliferative activities against the cancer cells than 1,25(OH)2D3, and 1,25-(OH)2-16,23Z-diene-26,27-bishomo-19-nor-D3 (Ro 27-2014) was the most potent analog [10-fold increased activity compared to 1,25(OH)2D3]. Further studies were performed using Ro 27-2014. Pulse-exposure studies showed that a 5-day pulse-exposure to Ro 27-2014 (10(-7) M) in liquid culture was adequate to achieve a 50% inhibition of MCF-7 clonal growth in soft agar in the absence of the analog, suggesting that the growth inhibition mediated by the analog was irreversible. Cell cycle analyses using MCF-7 cells showed that Ro 27-2014 (10(-7) M for 4 days) induced a significant increase in the number of cells in G0-G1 (72.8+/-8.9% versus 49.9+/-3.5% in control cells), with a concomitant decrease in the percent of cells in S phase (13.1+/-6.2% versus 35.8+/-3.5% in control cells). The chief toxicity of vitamin D3 compounds is hypercalcemia, and therefore, we examined calcemic activity of Ro 27-2014 in mice and found it not to induce hypercalcemia at doses of 0.05 microg i.p. three times per week. In contrast, the same dose of a 19-nor vitamin D3 compound with 6 fluorines on the side chain (1,25-(OH)2-16-ene-23-yne-26,27-F6-19-nor-D3), although also having potent anticancer activity, caused severe hypercalcemia (18 mg/dl). In summary, 19-nor vitamin D3 compounds with desaturation and lengthening of their side chains result in a series of compounds with a good therapeutic index, having potent anticancer activity and low toxicity.

Molecular cloning of the chromosomal breakpoint of a B-cell lymphoma with the t(11;14)(q23;q32) translocation.

The breakpoint of t(11;14)(q23;q32) chromosome translocation in a B-cell lymphoma line, RC-K8, was cloned. Immunoglobulin heavy chain (IGH) constant gene, C gamma 2 at the 5' end, was involved in this translocation, and the DNA segment juxtaposed to the C gamma 2 was proved to be derived from chromosome 11 by somatic cell hybrid study. The normal counterpart of chromosome 11 was also isolated. With a DNA probe near the breakpoint of chromosome 11, Southern blot analysis of RC-K8 and 10 other cases with translocation involving the 11q23 region was conducted, but no rearrangement bands have been observed thus far except for RC-K8.

Enhanced immunogenicity of the cultured rat fibrosarcoma KMT-17 by cultivation in a low concentration of fetal calf serum.

We examined in different culture conditions alterations in the tumorigenicity and immunogenicity of an A3 clone that had been derived from a rat fibrosarcoma KMT-17. When a fetal calf serum concentration in a culture medium was lowered from 10 to 1%, the tumorigenicity was diminished while the immunogenicity was enhanced in a reversible manner; this was accompanied by a reversible prolongation of the in vitro doubling time. These phenomena were not due to an increase in the quantities of the original tumor-associated antigen and/or of the rat major histocompatibility complex (RT1) but seemed to be due to the appearance of a unique antigen(s) that was detected by an antibody taken from rats immunized with A3 tumor cells cultured in the low fetal calf serum concentration; this antigen(s) may consist of glycoprotein and exist as a crypt antigen(s). These phenomena were measured by an absorption test and flow cytometric analysis. Our observations suggest that the in vitro culture condition of tumor cells, in particular their culturing in the low fetal calf serum concentration medium, modifies the surface of tumor cells and causes a diminishment in their tumorigenicity and an enhancement of their immunogenicity.

Allelotype analysis of childhood acute lymphoblastic leukemia.

To identify the genetic events that may play an important role in leukemogenesis of childhood ALL, we report for the first time the allelotyping of childhood ALL. Twenty-four cases of childhood ALL were screened for loss of heterozygosity (LOH) using 101 highly polymorphic microsatellite markers, which are distributed among all autosomal chromosomes. For LOH analysis on both chromosomes 9 and 12, 54 childhood ALL samples were examined. The most frequent allelic loss was found on chromosomal arm 9p, where 20 of 50 (40%) informative samples showed LOH. Moreover, nearly 30% of samples that did not have either homozygous deletions or point mutations of the putative tumor suppressor genes CDKN2/INK4A/p16 and INK4B/p15 on chromosomal arm 9p had LOH at D9S171. Loss of chromosomal arm 12p was also frequent (26%). Mutational analysis suggested that the altered gene on 12p is not the cyclin-dependent kinase inhibitor p27/Kip1, which is also on 12p. Several other regions that had LOH included 1p, 4q, 5p, 6q, 7p, 8p, 9q, 10q, 13q, 17p, 17q, 18q, 19q, and 22q. Of 24 patients, 19 (79%) showed allelic loss on at least one chromosomal arm. Samples of two patients (8%) showed LOH on almost all chromosomes. Fractional allelic loss, calculated for each sample as the total number of chromosomal arms lost/total number of arms with information, showed a median value of 0.04 and a mean of 0.123 (range, 0 to 0.95). This fractional allelic loss is lower than those reported for many solid tumors. This analysis shows the extreme power of LOH analysis using microsatellite markers in childhood ALL.

Two mouse monoclonal antibodies detecting two different epitopes of an activated lymphocyte antigen on adult T-cell leukemia cells.

Mouse monoclonal antibodies were produced against MT-2 cell line derived from adult T-cell leukemia or human T-cell leukemia virus-rich fraction therefrom. Two IgG1 antibodies, Ta60a and Ta60b, were found to be reactive not only with cell lines derived from adult T-cell leukemia or cutaneous T-cell lymphomas, but also with activated peripheral blood lymphocytes, suggesting the similarity of Ta60 antigen group to Tac antigen which is present on interleukin 2 receptor. Thus, the relationship among these antigens was studied. Two Ta60 antibodies and Tac antibody immunoprecipitated the molecule with almost identical electrophoretic mobility, approximately a Mr 60,000 antigen from [3H]glucosamine-labeled activated peripheral blood lymphocytes or MT-2, MT-1, or ATN-1 cells from adult T-cell leukemia and a Mr 53,000 antigen from HUT-102 cells derived from cutaneous T-cell lymphomas. Further, Tac antibody was found to immunoprecipitate Ta60b molecule on 125I-labeled MT-2 cells by sequential immunoprecipitation, indicating that these two epitopes are on the same molecule. Antibody binding inhibition assays with either 3H-labeled Ta60a or Ta60b antibody demonstrated that Ta60a and Tac are the same epitope, but different from Ta60b. Thus, at least two epitopes were demonstrated to be present on interleukin 2 receptor molecule. However, Ta60b antibody showed almost no blocking effects on proliferation of an interleukin-2-dependent cell line, whereas Ta60a antibody did. Various hematopoietic tumor cells were typed with these two antibodies, but the results with Ta60b antibody were described, because they showed a similar specificity. Ta60b antibody reacted with all adult T-cell leukemia cases, but did not react with T-cell acute lymphoblastic leukemia, lymphoblastic lymphoma, or mature T-cell lymphoma. Interestingly, 3 of 12 acute myeloblastic leukemia and 2 of 5 chronic myelocytic leukemia in blastic crisis showed positive reactions. One-third of B-cell chronic lymphocytic leukemia and B-cell lymphoma as well as a few B-cell lines were also weakly reactive with this antibody. A part of the results with direct tests was confirmed by the absorption tests. The results obtained demonstrated the presence of Ta60b on a certain fraction of malignant hematopoietic cells of other than T-cell origin.

Ligand for peroxisome proliferator-activated receptor gamma (troglitazone) has potent antitumor effect against human prostate cancer both in vitro and in vivo.

Troglitazone, a thiazolidinedione derivative, is a widely used antidiabetic drug that binds and activates peroxisome proliferator-activated receptor gamma (PPARgamma) and enhances insulin sensitivity. It induces differentiation of adipocytes, which highly express PPARgamma. We report that human prostate cancer cells expressed PPARgamma at prominent levels and normal prostate tissues had very low expression. Dose-response clonogenic assays of the PC-3 prostate cancer cell line with troglitazone showed an antiproliferative effect (ED50, 3 x 10(-7) M) and other PPARgamma ligands (BRL49653: ED50, 8 x 10(-8) M; 15-deoxy-delta12,14-prostaglandin J2: ED50, 2 x 10(-6) M; ciglitizone: ED50, not reached; indomethacin: ED50, not reached) showed similar effects. Combinations of troglitazone and a ligand specific for either retinoid X receptor or retinoic acid receptor did not show a synergistic effect. Pulse-exposure to troglitazone (10(-5) M) for different durations showed that 4 days of pulse-exposure to the agent irreversibly inhibited 50% clonal growth of PC-3 cells. Interestingly, PC-3 cells cultured with troglitazone (10(-5) M) showed dramatic morphological changes both by light and electron microscopy, suggesting that the cells became less malignant. Nevertheless, troglitazone did not affect either the cell cycle or several markers of differentiation. LNCaP cells constitutively produced prostate-specific antigen, and levels were markedly enhanced by all-trans-retinoic acid. Troglitazone (10(-5) M, 4 days) decreased by 50% the levels of prostate-specific antigen produced by these cells. In vivo treatment of PC-3 tumors growing in male BNX triple immunodeficient mice with oral troglitazone (500 mg/kg/day) produced significant inhibition of tumor growth (P = 0.01). The only objective side effect of troglitazone in mice was the elevation of serum transaminases. Short-term culture of four surgically obtained human prostate cancer tumors with troglitazone (10(-5) M, 4 days) produced marked and selective necrosis of the cancer cells (about 60%) but not the adjacent normal prostate cells. Taken together, these results suggest that troglitazone may be a useful therapeutic agent for the treatment of prostate cancer, especially in the setting of low disease burden.

Frequent loss of heterozygosity on the long arm of chromosome 6: identification of two distinct regions of deletion in childhood acute lymphoblastic leukemia.

Cytogenetic analysis of childhood acute lymphoblastic leukemia (ALL) identified nonrandom chromosomal abnormalities of the long arm of chromosome 6. Most of the alterations are deletions that are thought to be indicative of the presence of a tumor suppressor gene that is mutated on the remaining allele. These observations led us to consider whether 6q loss may contribute to the pathogenesis of childhood ALL. To define further a region containing this gene, we analyzed the loss of heterozygosity (LOH) of chromosome 6 in 113 primary ALL samples with matched normal DNA using 34 highly informative microsatellite markers. LOH was found in 17 (15%) samples at one or more of the loci, and partial or interstitial deletions of 6q were detected in 11 of these tumors. On the basis of these results, we performed a detailed deletional map and identified two distinct regions of deletion. The first region is flanked by D6S283 and D6S302 loci at 6q21-22. The second region is flanked by D6S275 and D6S283 loci at 6q21. Clinical analysis determined that LOH of 6q was demonstrated both in precursor-B cell ALLs (15 of 93; 16%) and in T cell ALLs (2 of 19; 11%). In addition, 19 patients have been studied at diagnosis and relapse; 18 showed the same 6q21-22 structural abnormality at relapse (normal, 16 patients; LOH, 2 patients) as their initial presentation, suggesting, albeit with a small patient sample size, that 6q21-22 deletions may be an initial event in leukemogenesis and may occur less frequently during the progression of childhood ALL. These data suggest the presence of putative tumor suppressor genes on chromosome arm 6q that are important in the development of both T and precursor-B childhood ALLs. Our map provides important information toward cloning putative ALL tumor suppressor genes.

Frequent loss of heterozygosity in region of the KIP1 locus in non-small cell lung cancer: evidence for a new tumor suppressor gene on the short arm of chromosome 12.

To refine the chromosomal localization of a putative tumor suppressor gene, we analyzed the loss of heterozygosity (LOH) of chromosome 12 in 36 primary non-small cell lung cancer (NSCLC) samples with matched normal DNA using 22 highly informative polymorphic markers. Twelve cases showed LOH at one or more loci on chromosome 12. LOH of chromosome arm 12p was more frequent in large cell carcinoma than squamous cell carcinoma, indicating molecular genetic heterozygosity within the major NSCLC subtypes. We identified the smallest commonly deleted region on chromosome 12p13. This region is flanked by D12S269 and D12S308, including the KIP1 gene. Mutational analysis of KIP1 using PCR-single strand conformation polymorphism and Southern Blot analysis showed no homozygous deletions, rearrangements, or point mutations, suggesting that the altered gene in this region is not the KIP1 gene. These data suggest that a new tumor suppressor gene which is involved in tumorigenesis of NSCLC is in the region of KIP1.

A Ki-1 (CD30)-positive T (E+, CD4+, Ia+)-cell line, DL-40, established from aggressive large cell lymphoma.

A new human lymphoma cell line, designated DL-40, was established from the peripheral blood of a 64-year-old woman with leukemic conversion of aggressive large cell lymphoma. The cell line grew in suspension with or without forming clumps of cells and exhibited large, round, or multiple nuclei in the relatively abundant cytoplasm that was positive for acid phosphatase. The cells expressed a Ki-1 antigen (CD30), E+, CD2+, CD4+, CD45+, Ia+ phenotype and had rearranged T-cell receptor beta chain but were negative for CD15, HTLV-I, and Epstein-Barr virus nuclear antigen. Chromosome analysis of this cell line showed a human female karyotype with complex hyperdiploid abnormalities. DL-40 cells produced tumors histologically similar to the original lymphoma when transplanted into nude mice and immunosuppressed hamsters. The DL-40 cell line could provide a useful tool for the understanding of biology of the Ki-1-positive non-Hodgkin's lymphoma.