[Study of the ploidy and cellular cycle of hidradenomas and hidradenocarcinomas: a series of 13 cases]. / Etude de la ploïdie et du cycle cellulaire des hidradenomes et des hidradenocarcinomes: a propos d'une série de 13 cas.

AIMS: To study by flow cytometry (FCM) the ploidy and the cellular cycle of nodular hidradenoma (NH) and hidradenocarcinoma (HC) and to assess the prognostic utility of this technique in such tumors. METHODS: We studied retrospectively 2 HC and 11 NH one of which was considered as an atypical NH. Monoparametric study by FCM was realized on paraffin-embedded material. The extracted cells were marked by Propidium's lodure and cellular cycle was analyzed by the software Mod-Fit LT. RESULTS: Our study showed eleven 100% diploid profiles, 10 of which had low S-phase varying between 2 and 12%. All of these 11 tumors were NH. S-phase was high (23.79%) in a single case that corresponded to the atypical NH. Two tumors showed aneuploid profiles; these corresponded to the 2 HC. CONCLUSION: The results of the cytometric study suit perfectly to those of the histopathologic examination. FCM could so help to establish the prognosis of these tumors. But further studies are necessary to determine the value of this technique.

Chromatographic separation of recombinant human erythropoietin isoforms.

Erythropoietin (EPO) is the main regulator of erythropoiesis. The human glycoprotein hormone is heterogeneous when analyzed by isoelectric focusing (IEF). We investigated the possibility of fractionating EPO isoforms using different chromatographic methods. A recombinant human EPO (rhEPO) was obtained from the culture supernatants of a human B-lymphoblastoid cell line transfected by the human EPO gene. Highly purified rhEPO preparations were obtained by immunoaffinity purification. More than fourteen isoforms were observed after IEF. Among the different methods developed for isoform fractionation, the most reproducible results were obtained by DEAE-Sephacel chromatography. Seven fractions of decreasing isoelectric point (pI) were obtained. The specific activity of these fractions measured by an immunoradiometric assay was not equally distributed.

[A human recombinant erythropoietin produced in human lymphoblastoid cells]. / L'érythropoïétine humaine recombinante produite dans des cellules lymphoblastoïdes humaines.

A human recombinant erythropoietin is produced by transfection of a human EBV immortalised lymphoblastoid cell line by human erythropoietin gene. This cell line was selected because it is eucaryotic, human, able to grow in suspension and neither clonogenic nor tumorigenic. Purification of erythropoietin from culture supernatants of lymphoblastoid cells was described and structural, biochemical and functional characteristics were investigated in several studies. Results obtained for this kind of recombinant erythropoietin were similar to those obtained regarding the protein expressed in CHO cells suggesting that both molecules have the same efficiency in clinical applications.

Efficient production of biologically active human recombinant proteins in human lymphoblastoid cells from integrative and episomal expression vectors.

The ability of human lymphoblastoid cells to secrete large amounts of biologically active human hematopoietic growth factors from adenovirus-based expression vectors was investigated. The gene for human erythropoietin (EPO) was inserted into integrative (pTS39) and episomal (pTS53) vectors. Cell clones, originating from pTS39 or pTS53-transfected and stably selected cells, secreted recombinant human EPO (re-hEPO) at similar levels. The highest production, 60 mu/10(6) cells per 24 h, was obtained from a subclone of pTS39-transfected cells, grown in nonselective medium. The re-hEPO was shown to be biologically active in vivo by incorporation of 59Fe into red blood cells of polycythemic mice and in vitro by the proliferative response of the EPO-dependent cell line UT7. The purified protein of 36 kDa in SDS-PAGE slightly differed from re-hEPO from CHO cells. pTS39 vector was integrated at 15-30 copies per genome, whereas the pTS53 vector replicated at 10 copies per cell. Genes encoding human interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were also expressed in the integrative system as biologically active growth factors, demonstrating that our host-vector system allows the expression of any little gene or cDNA and efficient secretion of the re-protein produced.

Purification and biological activity of a recombinant human erythropoietin produced by lymphoblastoid cells.

A recombinant human erythropoietin (rH-EPO) was obtained from the culture supernatants of human B-lymphoblastoid cells transfected by the human EPO gene. rH-EPO was purified by a two-step method based on immunoaffinity and ion exchange chromatography. The first step was achieved by an anti-EPO monoclonal antibody (Mab). This Mab, immobilized on Sepharose 4B, allowed a 410-fold purification of the protein. The second step consisted of ion exchange chromatography on DEAE Sephacel. The combination of these two steps results in a highly purified rH-EPO with a global yield of about 50%; the specific activity of the protein was 176,000 IU/A280. The NMR spectrum was characteristic for a well structured, single-conformation protein. The purified protein was analyzed by SDS-PAGE and isoelectric focusing. The biological activity of purified rH-EPO was measured in vivo, by the incorporation of 59Fe into red blood cells (RBC) of polycythemic mice and in vitro by the proliferative response of an EPO-dependent cell line. The purified protein expressed in lymphoblastoid cells of human origin had the same biological activity as that of urinary EPO and rH-EPO produced in other mammalian cells.

Preparation and biological properties of monoclonal antibodies against human erythropoietin.

Several monoclonal antibodies (Mabs) against human erythropoietin (H-EPO) were obtained by fusion of myeloma cells with splenocytes from mice immunized with purified recombinant H-EPO. Three Mabs (D7, E14 and E73) were selected by radioimmunoprecipitation on the basis of their high affinity against H-EPO. Their dissociation constants were 0.3 nM for E14 and D7, and 17 nM for E73. The immunochemical properties of these Mabs were analyzed in respect to their capacity to react, to purify, and to inhibit the biological activities of H-EPO. a) detection by Western blotting techniques: among the 3 Mabs only D7 was effective by this technique. b) purification: the best results were observed with E14, an approximately 200-fold purification of H-EPO from culture supernatants was obtained in a single immunopurification step. c) inhibition of the biological activity: the specific binding of 125I-labelled H-EPO to its cellular receptor was inhibited by E14 and E73 but not by D7. These three Mabs exhibited similar effects as far as the inhibition of the proliferation of H-EPO dependent cells (measured by 3H-thymidine incorporation) was concerned.