A new monoclonal antibody (CAL2) detects CALRETICULIN mutations in formalin-fixed and paraffin-embedded bone marrow biopsies

Recent advances in the diagnostic of myeloproliferative neoplasms (MPNs) discovered CALRETICULIN (CALR) mutations as a major driver in these disorders. In contrast to JAK2 mutations being mainly associated with polycythaemia vera, CALR mutations are only associated with primary myelofibrosis (PMF) and essential thrombocythaemia (ET). CALR mutations are present in the majority of PMF and ET patients lacking JAK2 and MPL mutations. As these CALR mutations are absent from reactive bone marrow (BM) lesions their presence indicates ET or PMF. So far these mutations are detectable only by molecular assays. Their molecular detection is cumbersome because of the great CALR mutation heterogeneity. Therefore, the availability of a simple assay would be of great help. All CALR mutations reported lead to a frameshift generating a new 36 amino-acid C-terminus. We generated a monoclonal antibody (CAL2) to this C-neoterminus by immunizing mice with a representative peptide and compared its performance with Sanger sequencing data in 173 MPNs and other BM diseases. There was a 100% correlation between the molecular and the CAL2 immunohistochemical (IHC) assays. Thus, the detection of CALR mutations by the CAL2 IHC is a specific, sensitive, rapid, simple and low-cost method.

Induction of the inflammatory regulator A20 by gibberellic acid in airway epithelial cells

BACKGROUND AND PURPOSE

NF-κB-driven inflammation is negatively regulated by the zinc finger protein A20. Gibberellic acid (GA3 ) is a plant-derived diterpenoid with documented anti-inflammatory activity, which is reported to induce A20-like zinc finger proteins in plants. Here, we sought to investigate the anti-inflammatory effect of GA3 in airway epithelial cells and determine if the anti-inflammatory action relates to A20 induction.

EXPERIMENTAL APPROACH

Primary nasal epithelial cells and a human bronchial epithelial cell line (16HBE14o-) were used. Cells were pre-incubated with GA3 , stimulated with Pseudomonas aeruginosa LPS; IL-6 and IL-8 release, A20, NF-κB and IκBα expression were then evaluated. To determine if any observed anti-inflammatory effect occurred via an A20-dependent mechanism, A20 was silenced using siRNA.

KEY RESULTS

Cells pre-incubated with GA3 had significantly increased levels of A20 mRNA (4 h) and protein (24 h), resulting in a significant reduction in IL-6 and IL-8 release. This effect was mediated via reduced IκBα degradation and reduced NF-κB (p65) expression. Furthermore, the anti-inflammatory action of GA3 was abolished in A20-silenced cells.

CONCLUSIONS AND IMPLICATIONS

We showed that A20 induction by GA3 attenuates inflammation in airway epithelial cells, at least in part through its effect on NF-κB and IκBα. GA3 or gibberellin-derived derivatives could potentially be developed into anti-inflammatory drugs for the treatment of chronic inflammatory diseases associated with A20 dysfunction.

Different T-bet expression patterns characterize particular reactive lymphoid tissue lesions

AIMS

To investigate T-bet expression profiles in various lymphoid tissue diseases caused by intracellular pathogens and to compare them in disorders without an infective aetiology. Murine and in vitro experiments have shown that the expression/induction of T-bet, the master regulator of Th1 differentiation, can be achieved by obligate intracellular pathogens and high interferon (IFN)-gamma levels.

METHODS

Lymph node biopsies were analysed immunohistochemically employing single and double labelling for T-bet and CD20, CD4, CD8 and CD30 detection.

RESULTS

In disorders associated with high IFN-gamma levels and intracellular pathogens (infectious mononucleosis, HIV-associated lymphadenopathy, cat-scratch disease, and toxoplasmic lymphadenitis), T-bet-expressing CD4 cells were accompanied by significant numbers of T-bet-positive CD8 and B cells. A similar profile was also found in histiocytic necrotizing (Kikuchi) lymphadenitis, a disease of unknown cause. In contrast, T-bet expression in disorders without an infective aetiology was observed in only a small portion of lymphocytes.

CONCLUSIONS

Increased T-bet expression does not only identify intracellular infections in lymphoid tissue associated with high IFN-gamma levels, but also implies that, under these conditions, it becomes induced in B cells, which apparently support the Th1 response. T-bet expression in Kikuchi lymphadenitis underscores the hypothesis that it is caused by an intracellular microorganism.

mRNA expression patterns indicate CD30 mediated activation of different apoptosis pathways in anaplastic large cell lymphoma but not in Hodgkin's lymphoma

One of the main functions of the tumor necrosis factor receptor (TNFR) family is induction of apoptosis. CD30, a member of the TNFR superfamily is overexpressed in highly proliferating tumors such as anaplastic large cell lymphoma (ALCL) and Hodgkin's lymphoma (HL). CD30 stimulation leads to apoptosis and growth arrest in cultured ALCL, but not in Hodgkin-Reed-Sternberg cells. To identify changes in the transcriptional program responsible for these opposing effects, we performed gene expression analysis in CD30-stimulated ALCL (Karpas 299) and HL (KM-H2) cell lines using cDNA microarrays. Selected genes were validated by real-time PCR. Hierarchical clustering was applied to the whole dataset and separated the cell lines clearly with respect to their origin. In HL, there were only minor CD30-specific alterations, whereas ALCL unequivocally showed a pronounced CD30-specific transcriptional response. Ninety-three genes (6.6% of total) were deregulated by more than a factor of two after CD30 stimulation in ALCL cells. The majority of genes identified are involved in cell cycle regulation and apoptosis. mRNA expression patterns further indicate that in contrast to HL, CD30 stimulation in ALCL induces cell death via the CD95-CD95 ligand (CD95L) pathway and the TNF-R1/TNF-R2 crosstalk. These data provide a detailed view on the transcriptional changes upon CD30 stimulation and may explain the observed functional differences of HL and ALCL.

Bisphosphonate und Osteonekrosen im Kieferbereich

BACKGROUND

Since 2003, reports have been published on necrosis of the jaw bones possibly being associated with the administration of bisphosphonates. Bisphosphonates are highly active inhibitors of osteoclasts which have been used prophylactically or symptomatically in the treatment of plasmocytoma, bone metastasis of malignant disease, tumor-associated hypercalcaemia and in the treatment of osteoporosis. Due to the importance of this side effect of bisphosphonates, we report six cases.

CASE REPORTS

Six patients (two women and four men) with a median age of 69 years (range 55-37) were diagnosed with osteonecrosis of the maxilla and/or mandible. These osteonecroses did not react adequately to local treatment and systemic therapy with antibiotics. Four patients suffered from plasmocytoma and two patients had a history of metastasising breast cancer. Besides cytostatic chemotherapies, all patients received bisphosphonates over an extended period.

DISCUSSION

Bisphosphonates are considered an important standard in the treatment of plasmocytoma and bone metastasis due to malignancies. Since 2003, several reports have been published describing patients in whom therapy resistant osteonecrosis of jaw bones occurred either after dental extractions or spontaneously. Until then, unknown side effects of bisphosphonate therapy had been suspected. Since patients with malignant diseases receive cytostatic therapy and a range of other drugs, including bisphosphonates, enhancement of the side effects may be presumed.

CONCLUSIONS

The probable association of the therapeutic use of bisphosphonates and the occurence of jaw bone necrosis has to be studied in further investigations. Patients receiving bisphosphonates should be followed-up regularly to avoid the occurrence of extended osteonecrotic lesions, which should be diagnosed early and treated adequately.

The IL-15R alpha chain signals through association with Syk in human B cells

The alpha-chain of the IL-15R (IL-15Ralpha) serves as the specific, high-affinity receptor for IL-15. It is expressed by lymphoid and nonlymphoid cells, including B cell lymphoma lines. In this study, we have further explored IL-15Ralpha-mediated signaling in activated primary B cells and in Raji cells, a human B-lymphoblastoid cell line which expresses the IL-15Ralpha and IL-2Rgamma chains, but lacks the IL-2Rbeta chain. Stimulation of Raji cells with IL-15 induces their proliferation and rescues them from C2-ceramide-induced apoptosis. By immunoprecipitation and Western blotting, we show that treatment of Raji cells and activated primary B cells with IL-15 induces coprecipitation of Syk kinase with the IL-15Ralpha chain. Upon association, the activated Syk kinase phosphorylates the IL-15Ralpha chain as well as phospholipase Cgamma, which coprecipitates with Syk. Furthermore, transfection of Raji cells with stem-loop Syk antisense oligonucleotides prevents IL-15Ralpha and phospholipase Cgamma phosphorylation as well as the inhibition of apoptosis by IL-15. Mutation of a defined region of the intracellular signaling portion of IL-15Ralpha (Tyr227) abrogates both the IL-15Ralpha/Syk association and IL-15Ralpha phosphorylation. Taken together, this suggests that Syk kinase physically and functionally associates with the IL-15Ralpha chain in B cells and that Syk plays a key role in mediating IL-15-induced signal transduction, thus accounting for the distinct functional consequences of IL-15 vs IL-2 binding to B cells.

Structure of the Hodgkin's lymphoma-associated human CD30 gene and the influence of a microsatellite region on its expression in CD30(+) cell lines

The CD30 antigen is a member of the tumor necrosis factor receptor (TNFR) family which is overexpressed on the surface of the tumor cells of Hodgkin's lymphoma, anaplastic large cell lymphoma (ALCL), and embryonal carcinoma of the testis. In this study the entire cd30 gene which is more than 24000 bp long and organized in eight exons was characterized by analyzing cosmid and phage lambda clones from human placental libraries with long-range polymerase chain reaction (PCR) and sequencing. Differences to other genes of the TNFR family were detected in the region encoding the extracellular domain of the cd30 gene. In nearly all other TNFR genes, the coding region of each cysteine-rich repeat is interrupted by one intron, i.e., the 3-4 cysteine-rich repeats of these receptors are encoded by at least 4-5 exons, whereas the six cysteine-rich repeats of the cd30 gene are encoded by two exons, i.e., each of these exons encode three cysteine-rich repeats. In addition, we also found a genetic polymorphism of tetranucleotide ATCC-repeats in the 5' part of the CD30 promoter. This region was amplified by PCR from seven CD30 overexpressing human lymphoid cell lines and five human tissues with an absent or very low CD30 expression. The amplification products showed length differences of more than 550 bp. The number of the ATCC-repeats was higher in CD30(+) cell lines than in normal tissues. Comparison of the individual PCR products in reporter gene assays revealed that the CD30 promoter activity increased with the length of this polymorphic region up to eightfold. The data suggest that the number of ATCC-repeats in the 5' region of the CD30 promoter modulates the regulation of CD30 expression.

CD30(+) anaplastic large cell lymphoma: a review of its histopathologic, genetic, and clinical features

Anaplastic large cell lymphoma (ALCL) represents a generally recognized group of large cell lymphomas. Defining features consist of a proliferation of predominantly large lymphoid cells with strong expression of the cytokine receptor CD30 and a characteristic growth pattern. With the use of molecular and clinical criteria, 3 entities of ALCL have been identified: primary systemic anaplastic lymphoma kinase (ALK)(+) ALCL, primary systemic ALK(-) ALCL, and primary cutaneous ALCL. ALK expression is caused by chromosomal translocations, most commonly t(2;5). ALK(+) ALCL predominantly affects young male patients and, if treated with chemotherapy, has a favorable prognosis. It shows a broad morphologic spectrum, with the "common type," the small cell variant, and the lymphohistiocytic variant being most commonly observed. The knowledge of the existence of these variants is essential in establishing a correct diagnosis. ALK(-) ALCL occurs in older patients, affecting both genders equally and having an unfavorable prognosis. The morphology and the immunophenotype of primary cutaneous ALCL show an overlap with that of lymphomatoid papulosis. Both diseases have an excellent prognosis, and secondary systemic dissemination is only rarely observed. The described ALCL entities usually derive from cytotoxic T cells. In contrast, large B-cell lymphomas with anaplastic morphology are believed to represent not a separate entity but a morphologic variant of diffuse large B-cell lymphoma. Malignant lymphomas with morphologic features of both Hodgkin disease and ALCL have formerly been classified as Hodgkin-like ALCL. Recent immunohistologic studies, however, suggest that ALCLs Hodgkin-like represent either cases of tumor cell-rich classic Hodgkin disease or (less commonly) ALK(+) ALCL or ALK(-) ALCL. (Blood. 2000;96:3681-3695)

The restricted expression pattern of the Hodgkin's lymphoma-associated cytokine receptor CD30 is regulated by a minimal promoter

One of the most peculiar immunohistological characteristics of the tumour cells of Hodgkin's lymphoma, anaplastic large cell lymphoma (ALCL), and embryonal carcinoma of the testis is the expression of the CD30 antigen. Physiologically, CD30 expression is restricted to a few activated lymphocytes in normal lymphoid tissue and a small population of decidual cells. To clarify the reasons behind this highly restricted expression pattern and to learn about the combination of transcription factors involved in this regulation in Hodgkin's lymphoma and other CD30(+) malignancies, the 5'-flanking regulatory region of the cd30 gene was analysed. The major transcription start site was determined to be 270 bases upstream of the translational start codon in the Hodgkin's lymphoma-derived cell lines L591 and L428. Reporter gene assays revealed that the CD30 promoter (-413 to 84) induces a 50- to 1000-fold higher luciferase expression in CD30(+) human lymphoid cell lines (Co, Jurkat, and the Hodgkin's lymphoma-derived cell line L540) than in CD30(-) human lymphoid cell lines (DG75, SUP-T1, and U698M), CD30(-) human carcinoma cell lines (HeLa and MCF-7), or COS1 cells. Deletion analysis defined a TATA-less, minimal promoter sequence from -164 to 84. The transcription factor Sp1 and members of the Ets family induce CD30 expression, whereas the transcription factor Sp3 diminishes its induction. These data suggest that a high Sp1/Sp3 expression ratio and a peculiar expression pattern of the Ets transcription factors are involved in the overexpression of CD30 and might contribute to the transformation of CD30(+) tumour cells.

The HTLV-I tax protein transcriptionally modulates OX40 antigen expression

OX40 is a member of the TNF receptor family, expressed on activated T cells. It is the only costimulatory T cell molecule known to be specifically up-regulated in human T cell leukemia virus type-I (HTLV-I)-producing cells. In a T cell line, OX40 surface expression was shown to be induced by HTLV-I Tax alone. To understand molecular mechanisms of OX40 gene regulation and modulation by HTLV-I Tax, we have cloned the human OX40 gene and analyzed its 5'-flanking region. By reporter gene analysis with progressive 5' deletions from nucleotides -1259 to -64, we have defined a 157-bp DNA fragment as a minimal promoter for constitutive expression. In addition, we show that in the OX40+ cell line, Co, Tax is able to further increase OX40 surface expression. Up-regulation of OX40 promoter activity by Tax requires two upstream NF-kappaB sites, which are not active in the constitutive OX40 expression. Their deletion abrogates Tax responsiveness in reporter gene analysis. The site-directed mutagenesis of each NF-kappaB site demonstrates that cooperative NF-kappaB binding is a prerequisite for Tax-directed activity as neither site alone is sufficient for a full Tax responsiveness of the OX40 promoter. Upon Tax expression, both sites bind p65 and c-Rel. These data provide new insight into the direct regulation of OX40 by Tax and add to our understanding of the possible role of the OX40/OX40 ligand system in the proliferation of HTLV-I+ T cells.

Expression of the CD30 antigen in non-lymphoid tissues and cells

Originally, expression of the CD30 antigen was shown to be typical of the tumour cells of Hodgkin's disease (HD) and of anaplastic large cell lymphomas (ALCLs). In reactive lymphoid tissue, CD30 is expressed only in a small population of activated lymphoid blasts. Since then, several reports have been published describing CD30 expression in non-lymphoid tissues and malignancies, such as embryonal carcinomas (ECs), seminomas, cultivated macrophages, two histiocytic neoplasms, decidual cells, and mesotheliomas. As CD30 detection is important in the differential diagnosis of HD and ALCL, the expression of CD30 in different non-lymphoid tissues was re-evaluated by immunohistology and in situ hybridization. Extra-lymphoid CD30 expression was found in 48/51 cases of EC or EC components of germ cell tumours, in decidual cells of 1/10 cases, in activated mesothelium in 16/28 pleural and peritoneal effusions, and in small foci of tumour cells in 2/8 mesotheliomas. CD30 expression was not confirmed in 27 germ cell tumours of the testis without an EC component nor in cultivated macrophages and 17 histiocytic malignancies. The knowledge of these CD30 expression patterns is important for the immunohistological differential diagnosis of anaplastic tumours. The absence of CD30 expression in reactive and neoplastic macrophages does not favour the concept that HD and ALCL are derived from these cells.

Three new types of Apaf-1 in mammalian cells

Apaf-1, the human C. elegans Ced-4 homologue, plays a crucial role in mitochondrial mediated apoptosis. To determine whether a mutant Apaf-1 is involved in the pathogenesis of malignant lymphomas, we performed sequence analysis of its transcriptional gene product. Therefore, cDNAs coding for Apaf-1 were examined in six lymphoma derived cell lines, in three non-lymphoid tumor cell lines, as well as in peripheral blood lymphocytes and in tissue from heart, kidney, and liver by RT-PCR. These studies did not disclose the expected tumor related alterations but led instead to the identification of three novel forms of Apaf-1. These forms vary in length, but contain all functional domains formerly characterized in the Apaf-1 protein. The results indicate that the previously published sequence is not the Apaf-1 form most widely expressed.

Induction of cell death by tumour necrosis factor (TNF) receptor 2, CD40 and CD30: a role for TNF-R1 activation by endogenous membrane-anchored TNF

Several members of the tumour necrosis factor receptor (TNF-R) superfamily can induce cell death. For TNF-R1, Fas/APO-1, DR3, DR6, TRAIL-R1 and TRAIL-R2, a conserved 'death domain' in the intracellular region couples these receptors to activation of caspases. However, it is not yet known how TNF receptor family members lacking a death domain, such as TNF-R2, CD40, LT-betaR, CD27 or CD30, execute their death-inducing capability. Here we demonstrate in different cellular systems that cytotoxic effects induced by TNF-R2, CD40 and CD30 are mediated by endogenous production of TNF and autotropic or paratropic activation of TNF-R1. In addition, stimulation of TNF-R2 and CD40 synergistically enhances TNF-R1-induced cytotoxicity. These findings describe a novel pro-apoptotic mechanism induced by some members of the TNF-R family.

Tumor necrosis factor receptor-associated factor 1 is overexpressed in Reed-Sternberg cells of Hodgkin's disease and Epstein-Barr virus-transformed lymphoid cells

The tumor necrosis factor (TNF) receptor-associated factor 1 (TRAF1) is a member of the recently defined TRAF family. It takes part in the signal transduction of the TNF receptor 2 (TNFR2), the lymphotoxin-beta receptor (LT-betaR), CD40, CD30, and LMP1; is induced by LMP1 in vitro; and protects lymphoid cells from apoptosis. To identify the cells in which TRAF1 is active in vivo, we studied TRAF1 transcripts in normal lymphoid tissue, in Epstein-Barr virus (EBV)-induced lymphoproliferations, and in malignant lymphomas with special reference to those that overexpress the cytokine receptor CD30 and CD40 of the TNF receptor family at the single-cell level using a radioactive in situ hybridization. In normal lymphoid tissue, TRAF1 message proved to be absent from all resting B and T cells as well as from macrophages and accessory cells (follicular dendritic cells and interdigitating cells) and present in few perifollicular and intrafollicular lymphoid blasts. In contrast, there was a high and consistent TRAF1 overexpression in EBV-induced lymphoproliferations and Hodgkin's disease. Nearly all non-Hodgkin's lymphoma show low or no TRAF1 expression. Only some cases of diffuse large B-cell lymphoma showed a moderate to high TRAF1 signal. Several of the latter cases were EBV+. These data confirm that TRAF1 is an inducible molecule and indicates its deregulation in the mentioned disorders with the potential of a blockage of the apoptotic pathway.

TNFR80-dependent enhancement of TNFR60-induced cell death is mediated by TNFR-associated factor 2 and is specific for TNFR60

Costimulation of TNFR80 can strongly enhance TNFR60-induced cell death. In this study, we show that this enhancement is TNFR60 selective, as neither TNF-related apoptosis-inducing ligand/Apo2 ligand-, Apo1/Fas-, ceramide-, nor daunorubicin-mediated cell death was affected by costimulation of TNFR80. We further demonstrate that TNFR-associated factor 2 (TRAF2) is critically involved in both negative and positive regulation of TNF-induced cell death. Overexpression of TRAF2 and of a TRAF2 mutant, deficient in nuclear factor-kappaB activation, selectively desensitized and enhanced, respectively, TNFR60-induced cell death in HeLa cells. However, upon costimulation of TNFR80, which mediates activation of nuclear factor-kappaB and the c-Jun amino-terminal kinase via TRAF2, TNF-induced cell death is drastically enhanced in parental and TRAF2-transfected, but not in TRAF2 (87-501)-transfected cells. These data point to a critical role of TRAF2 in the apoptotic TNFR cross talk, whereby the TNFR80-dependent enhancement of TNFR60-induced cell death is due to TNFR80-mediated negative regulation of TRAF2 function(s). An interference with TRAF2 function was confirmed independently by analysis of c-Jun amino-terminal kinase activation via TNFR60 upon prestimulation of TNFR80. We propose that the apoptotic TNFR cross talk is based on TNFR80-mediated abrogation of antiapoptotic TRAF2-dependent signaling pathways initiated by TNFR60, but not Apo1/Fas or the apoptotic TNF-related apoptosis-inducing ligand receptors.

Expression of several members of the TNF-ligand and receptor family on tonsillar lymphoid B cells

Although the expression patterns of the members of the tumour necrosis factor receptor and ligand families have extensively been studied by flow-cytometry on stimulated peripheral blood mononuclear cells (PBMNC), little or no flow-cytometric or immunohistological data exist about their expression in lymphoid tissue. According to the data obtained from stimulated PBMNC, several members of these molecule families (e.g. CD40 ligand [CD40L], CD30, CD27, hOX40) have been considered to be either T-cell restricted or strongly T-cell associated. The present study on samples from palatine tonsils revealed that most of these molecules are also expressed by tonsillar B cells. The additional analysis of the co-expression of these molecules also disclosed the existence of CD40+/CD40L+ and CD27+/CD70+ (CD27L+) lymphoid cells in tonsillar tissue.

Differential regulation of human T lymphoblast functions by IL-2 and IL-15

Interleukin 15 (IL-15) shares many functional properties with interleukin 2 (IL-2), although both cytokines probably also exert distinct functions. In order to screen for functional differences between IL-2 and IL-15 with respect to the control of T cell functions, we have stimulated human T lymphoblasts (hTBl) with IL-2 and/or IL-15 and have assessed the resulting changes in the following parameters: T cell proliferation; expression of various relevant surface markers; cytokine and receptor (alpha-chain) transcription; and IL-2 and IL-15 activity. Both cytokines equally upregulate standard activation markers such as CD25 and CD95 and downregulate CD27. However, IL-2 upregulates CD30, TNF receptor type II and CD40L expression significantly stronger than IL-15. IL-15 potentiates Con A-induced IL-2 secretion. Even though hTBl transcribe the IL-15 gene, they do not secrete IL-15 activity. These observations suggest that both cytokines can differentially regulate T cells, e.g. T cell functions relevant to the control of cell cycle progression and apoptosis, and/or that they can stimulate different T cell subsets. Moreover, IL-15 may potentiate IL-2-driven T cell responses.

Expression of the human OX40 (hOX40) antigen in normal and neoplastic tissues

The Ber-ACT35 mAb was raised against the human T-cell lymphotrophic virus (HTLV) 1-transformed, CD4+ HUT 102 cell line and recognizes the human homologue of the OX40 (hOX40) antigen. The analysis of the expression of hOX40 by immunohistochemical techniques in malignant lymphomas, carcinomas and non-malignant tissues of different organs shows that hOX40 expression was almost completely restricted to T lymphocytes. Besides T cells only a small subpopulation of macrophages in Langerhans' cell histiocytosis and a few blasts in B-cell non-Hodgkin's lymphoma (B-NHL) revealed a faint immunostaining with the Ber-ACT35 mAb. Furthermore, most of the hOX40+ T-cells are CD4+.

ALK gene products in anaplastic large cell lymphomas and Hodgkin's disease

The translocation t(2;5)(p23;q35), discovered in CD30+ anaplastic large cell (ALC) lymphomas, creates a potentially oncogenic fusion gene, part of which is contributed by a novel tyrosine kinase, ALK. Absence of ALK expression from normal hematolymphoid cells provides a basis for the morphologic assessment of t(2;5). The distribution of the t(2;5) in ALC lymphomas and Hodgkin's disease (HD), as assayed by nonmorphologic methods, is controversial. We used in situ hybridization and/or immunohistology to show ALK gene products in 85 ALC lymphomas, 82 HD cases, 40 other lymphoproliferations, as well as in 6 HD- and 4 ALC lymphoma-derived cell lines. ALK gene products were restricted to t(2;5)-positive ALC lymphoma cell lines and tumor cells of 16 primary non-B cell, common-type ALC lymphomas. These were mainly from young patients with initial lymphonodal disease. ALK expression was not detectable in any other specimen, including all cases of HD and HD-like type ALC lymphoma as well as secondary ALC lymphomas. Full congruence was noted for labeling results obtained with both methods. In agreement with cytogenetic analyses, but at variance with recently published studies, ALK gene expression distinguishes a subset of ALC lymphomas from other CD30+ lymphomas, including HD. The results do not support concepts attributing a significant role to the t(2;5) in the development of HD.

Differential sensitivity of CD30+ neoplastic cells to gelonin delivered by anti-CD30/anti-gelonin bispecific antibodies

Lymphocyte activation antigens, such as CD30, represent suitable target molecules for antibody-driven drug delivery in haemopoietic malignancies. A ribosome-inactivating protein (RIP) type 1 of potential interest for mAb targeting is gelonin, which displays a lower toxicity, as compared to other RIPs. In this study, two anti-CD30/antigelonin bispecific monoclonal antibodies (bimAbs), secreted by hybrid hybridomas, were used to deliver this RIP to CD30+ tumour cells. The two bimAbs, termed D4 and A18, were produced using the same anti-CD30 mAb and two anti-gelonin mAbs, directed to unrelated epitopes of the gelonin molecule. These bimAbs enhanced gelonin toxicity (IC50 5 x 10(-8) M, in the absence of mAbs) against the CD30+ L540 Hodgkin's lymphoma cell line in a protein synthesis inhibition assay. Thus, in the presence of 10(-9) M D4 bimAb, protein synthesis was inhibited with an IC50 of 5 x 10(-10) M as gelonin, whereas with A18 bimAb the IC50 was 8 x 10(-11) M. More interestingly, the combined use of the two bimAbs had a synergistic effect, since the IC50 of gelonin reached 6 x 10(-12) M. Among CD30 tumour cell lines, the Hodgkin's lymphoma L428 was also sensitive to gelonin delivered by bimAbs (IC50 6 x 10(-11) M), whereas the COLE Hodgkin's cell line and the T-ALL Jurkat were completely resistant to the toxic effect of gelonin and bimAbs. COLE and Jurkat cells were also resistant to a gelonin/anti-CD30 conventional immunotoxin, whereas they were sensitive to a saporin/anti-CD30 immunotoxin. This suggests that the resistance to gelonin is not related to a lack of internalization through the CD30 molecule but is associated with some property of the RIP.

CD30 antigen in embryonal carcinoma and embryogenesis and release of the soluble molecule

The expression, serological detection, and possible functional role of the CD30 antigen in Hodgkin's disease and anaplastic large cell lymphoma is well documented. In embryonal carcinoma (EC), the expression of this cytokine receptor has been demonstrated only by immunohistology. Because the CD30 monoclonal antibody Ki-1 was found to cross-react with an unrelated molecule, we examined by in situ hybridization testicular germ cell neoplasms for the presence of CD30-specific transcripts. CD30 mRNA was detectable in the tumor cells of 9 of 9 cases of EC or mixed germ cell tumors with an EC component but in no other nonlymphoid tumors. Thus, the CD30 transcript expression pattern proved to be identical to the immunostaining pattern seen with the CD30-specific monoclonal antibody Ber-H2. By Northern blot analysis, CD30 transcripts could be demonstrated in the EC cell line Tera-2. Employing a highly sensitive second generation sandwich enzyme-linked immunosorbent assay, we could detect the soluble CD30 molecule in 8 of 8 sera from patients with a diagnosis of EC but not in 8 of 10 sera from patients with other testicular germ cell tumors. In fetal tissue, no CD30-expressing germ cells or epithelial cells could be observed. Thus, the cellularly expressed CD30 marker for testicular neoplasms of EC type. Moreover, the serum levels of soluble CD30 antigen seem to be a promising parameter for monitoring patients with EC.

The human OX40 homolog: cDNA structure, expression and chromosomal assignment of the ACT35 antigen

Tissue distribution and expression on mitogen and virally stimulated lymphocytes render the ACT35 molecule a human lymphocyte activation antigen which as yet could not be clustered. Expression cloning of the ACT35 antigen from a pCDM8 library of the HUT-102 cell line revealed strong homology of the cDNA and its encoded protein sequence with the formerly described rat OX40 antigen. The 1.4-kb nucleotide sequence and the deduced 277-amino acid sequence of the single transmembrane protein were 65% and 63% identical, in human and in rat, respectively. Conservation included one N-linked glycosylation site and one protein kinase C phosphorylation site. When expressed in COS-1 cells, the cDNA presented properties comparable to the native ACT35 antigen and the rat OX40 molecule (relative molecular mass 48,000). Thus, the ACT35 protein corresponds to the hitherto unknown human OX40 antigen and is, therefore, another member of the tumor necrosis factor/nerve growth factor receptor (TNFR/NGFR) family. After applying fluorescence in situ hybridization, the human ACT35/OX40 gene could be mapped to chromosome band 1p36 and is, thus, linked to the genes for TNFR II and CD30.

In vivo targeting of Hodgkin and Reed-Sternberg cells of Hodgkin's disease with monoclonal antibody Ber-H2 (CD30): immunohistological evidence

The ability of the Ber-H2 (CD30) monoclonal antibody (mAb) to target in vivo Hodgkin (H) and Reed-Sternberg (R-S) cells was investigated in six patients with advanced Hodgkin's disease (HD). The patients were injected with scaled-up quantities of 'cold' Ber-H2 mixed-up to a small dose of 131I-labelled Ber-H2, and in vivo binding of the antibody to H and R-S cells was assessed by immunohistological analysis of tumour biopsies and immunoscintigraphy. Only 50% of tumour sites were imaged at scintigraphy by the 131I-labelled Ber-H2. In contrast, immunohistological studies on tissue biopsies, taken 24-72 h following the mAb injection, showed that H and R-S cells in all tumour sites, including those that were not imaged by immunoscintigraphy, were specifically and strongly labelled in vivo by the injected Ber-H2, at a dose as low as 30-50 mg of antibody. In vivo binding of a single dose of Ber-H2 mAb to H and R-S cells did not result in any anti-tumour effect. The excellent in vivo targeting of H and R-S cells with the Ber-H2 mAb may have been the result of multiple favourable factors, including: (a) the restricted expression of the CD30 antigen in normal human tissues; (b) the low level of soluble CD30 in the serum of our patients; and (c) the high affinity of the Ber-H2 mAb for the CD30 molecule. The immunohistological results presented in this study provide a strong argument for using the Ber-H2 mAb as a carrier for delivering cytotoxic agents (isotopes or toxins) to neoplastic cells of HD refractory to conventional therapy.

Response of refractory Hodgkin's disease to monoclonal anti-CD30 immunotoxin

In Hodgkin's disease, Hodgkin and Reed-Sternberg cells consistently express the antigen CD30. We investigated the possible therapeutic role of an immunotoxin prepared by covalent linking of an anti-CD30 monoclonal antibody (Ber-H2) to saporin (SO6), a type-1 ribosome-inactivating protein. The immunotoxin (0.8 mg/kg in one or two doses) was given to four patients with advanced refractory Hodgkin's disease. In three, there was rapid and substantial reduction in tumour mass (50% to greater than 75%). Clinical responses were transient (6-10 weeks). In-vivo binding of the immunotoxin to tumour cells was shown by immunohistology in two patients. Antibodies to both parts of the immunotoxin developed in all patients.

Molecular cloning and expression of a new member of the nerve growth factor receptor family that is characteristic for Hodgkin's disease

In man, Hodgkin's disease (HD) represents the most frequent lymphoma entity whose pathogenesis is still unknown. In order to contribute to the characterization of the molecular mechanisms of this disease, cDNAs coding for the HD characteristic antigen CD30 were cloned from expression libraries of the human HUT-102 cell line using the monoclonal antibodies Ki-1 and Ber-H2. The open reading frame of the cDNA that can be translated from two mRNA species of 2.6 kb, and 3.8 kb, respectively, predicts a 595 amino acid protein with leader, extracellular, single transmembrane, and intracellular domains. When expressed in COS-1 cells, the cDNA presented properties comparable to native CD30 antigen. The CD30 extracellular domain proved to be homologous to members of the nerve growth factor receptor superfamily. Six cysteine-rich motifs could be recognized within the putative ligand-binding domain.

HML-1 antigen on mucosa-associated T cells, activated cells, and hairy leukemic cells is a new integrin containing the beta 7 subunit

The monoclonal antibodies HML-1, B-ly7 and Ber-ACT8 recognize intramucosal gut T lymphocytes, activated cells, and hairy cell leukemia. The antigen on hairy cells consists of three glycoproteins (160 kappa D, 130 kappa D and 105 kappa D unreduced; 145 kappa D and 120 kappa D reduced). These peptides have biochemical features reminiscent of integrins but we have shown by immunoprecipitation that they are not known integrin subunits. We have used a newly produced antibody (BP6) to purify this molecule and shown by N-terminal sequence analysis that the smallest subunit is the product of integrin beta 7 cDNA. This molecule is thus a new member of the integrin family of leucocyte adhesion proteins. Immunoprecipitation experiments indicate that the two larger subunits are recognized by HML-1, B-ly7 and Ber-ACT8.

Undulin is a novel member of the fibronectin-tenascin family of extracellular matrix glycoproteins

We characterized cDNA clones specific for the extracellular matrix glycoprotein undulin. Two sets of cDNA clones were isolated from a human placental lambda gt11 expression library and from a rhabdomyosarcoma cell line encoding two partially identical carboxyl-terminal polypeptides of 843 (Un1) and 443 (Un2) amino acids suggesting differential splicing of a single gene transcript. Northern blot analysis of human rhabdomyosarcoma cell poly (A) RNA with cDNA specific for Un1 identified transcripts of approximately 4.2, 6.5, and 8.5 kilobases, whereas a probe specific for Un2 detected a single mRNA of approximately 5 kilobases. Since a monoclonal antibody that is reactive with a sequence encoded by Un1 and not by Un2 detects the bands considered characteristic for undulin in Western blots, the mRNAs related to Un1 may code for the major part of the undulin molecule. The protein sequences deduced from Un1 and Un2 reveal an amino-terminal differentially spliced von Willebrand factor A domain, characteristic of proteins that interact with interstitial collagens, which is linked to fibronectin-like type III homology units by a unique sequence of 57 amino acids. Whereas Un2 encodes two complete and one incomplete type III homologies followed by a unique acidic carboxyl-terminal domain of 118 amino acids, Un1 codes for seven complete and one truncated type III homologies, followed by a short proline-rich carboxyl-terminal segment of 23 amino acids. Considering the 298 amino acids occurring in identical segments, the 989 different amino acid positions deduced from clones Un1 and Un2 represent an estimated 40% of the overall undulin sequence. In the context of 1) rotary shadowing electron microscopy data showing undulin as a structure composed of nodules that are interconnected by flexible rods of varying size, 2) the presence of three major bands of Mr 270,000, 190,000, and 180,000 in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, with 3) common antigenic epitopes and similar peptide maps (Schuppan, D., Cantaluppi, M.C., Becker, J., Veit, A., Bunte, T., Troyer, D., Schuppan, F., Schmid, M., Ackermann, R., and Hahn, E.G. (1990) J. Biol. Chem. 265, 8823-8832), our finding of differentially spliced type III homology units, as found in tenascin and fibronectin, suggests that undulin is another member of the fibronectin-tenascin family of extracellular matrix glycoproteins. Furthermore, as in fibronectin and tenascin, undulin bears an additional subset of interactive domains tailored to specific structural and functional roles in development and differentiation.

BER-H2: a new anti-Ki-1 (CD30) monoclonal antibody directed at a formol-resistant epitope

The production and characterization of a monoclonal antibody (MoAb) designated Ber-H2, directed against a new epitope of the Ki-1 (CD30) antigen, are described. In comparison with the formerly reported Ki-1 MoAb whose reactivity with Hodgkin and Reed-Sternberg (H-RS) cells in frozen tissue sections is well-documented, the Ber-H2 MoAb showed new, important features: the labeling intensity of the Ber-H2 MoAb was much stronger, and the number of positively labeled cells was higher. Most important, however, was that the Ber-H2 MoAb could be applied in routinely processed, formaldehyde-fixed, paraffin-embedded tissue sections. Therefore, it was possible to investigate an unprecedented number of tumors received as frozen or formaldehyde-fixed material for expression of the CD30 antigen. Beside Hodgkin's disease, the Ber-H2 MoAb labeled a variable number of cells in lymphomatoid papulosis, peripheral T-cell lymphomas, and angoimmunoblastic lymphadenopathy. Among B-cell non-Hodgkin's lymphomas (NHLs), some cases containing large centroblast-like or immunoblast-like cells or displaying plasma-cellular differentiation were positive. This finding was in keeping with the reactivity of the Ber-H2 MoAb with activated B-cell blasts and a subpopulation of plasma cells in paraffin sections of normal lymphoid tissue. The diagnostic value of the Ber-H2 MoAb was most significant for a group of anaplastic large-cell (ALC) lymphomas (formerly frequently referred to as malignant histiocytosis or regressive atypical histiocytosis), of which more than 50 cases could be investigated, owing to applicability in paraffin sections. Although about one third of these ALC lymphomas did not express the leukocyte common (CD45) antigen, they were consistently reactive with the Ber-H2 MoAb in both frozen and paraffin-embedded tissue sections. Using the Ber-H2 MoAb, these Ki-1 lymphomas could be easily distinguished from other nonlymphoid anaplastic large-cell tumors.

Ki-1 (CD30) antigen is released by Ki-1-positive tumor cells in vitro and in vivo. I. Partial characterization of soluble Ki-1 antigen and detection of the antigen in cell culture supernatants and in serum by an enzyme-linked immunosorbent assay

An enzyme-linked immunosorbent assay (ELISA) has been developed that allows the quantitative determination of the Ki-1 (CD30) antigen in soluble form. Similar levels of sensitivity of this new Ki-1 ELISA and the ELISA previously described for measuring the soluble 55-kDa chain of the interleukin 2 receptor were seen. As assessed with this ELISA, the investigated Ki-1+ permanent cell lines released the Ki-1 antigen into the culture supernatant. In culture supernatants of concanavalin A-activated human peripheral blood lymphocytes, however, this antigen could not be detected. The released Ki-1 antigen has an apparent molecular weight (Mr) of 85,000, whereas the cell-associated Ki-1 antigen has an Mr of 105,000. We investigated sera from 30 normal donors, 15 patients with systemic infections, and 63 patients suffering from lymphomas for soluble Ki-1 antigen. In all sera from normal donors and patients with systemic infectious diseases, soluble Ki-1 antigen was below the detection limit (i.e., less than 70 pg). In contrast, high amounts of the soluble Ki-1 antigen were found in sera from 18 malignant lymphomas containing Ki-1+ tumor cells. This finding demonstrates that the release of the Ki-1 antigen takes place not only in vitro, but in vivo as well. Moreover, these results imply that the Ki-1 antigen may be used as a serum tumor marker.