Biomedical subjects

P Ujházy

Publications and source records attributed to P Ujházy.

At least 19 recordsLinked to original sources

PubMed2000

Protective specific immunity induced by doxorubicin plus TNF-alpha combination treatment of EL4 lymphoma-bearing C57BL/6 mice.

The therapeutic efficacy of a single (day 8), moderate dose (4 mg/kg, i.v.) of doxorubicin (DOX, Adriamycin) combined with recombinant human TNF-alpha (3 different doses and 5 different schedules, i.v.) was evaluated in C57BL/6 mice bearing an implant (s.c.) of the DOX-sensitive, TNF-alpha-resistant EL4 lymphoma. In parallel to monitoring survival, the levels of several host anti-tumor cytolytic effector functions of splenocytes and thymocytes were evaluated throughout the treatment period and in long-term survivors (LTS). DOX treatment alone resulted in a moderate (approx. 20%) increase in life span but no cures. TNF-alpha alone, at any tested dose or schedule, had little or no positive effect on survival. The combinations of DOX and TNF-alpha were only slightly better than DOX alone with respect to the time to death of mice that died (approx. 29% increase); however, each of the combinations involving 1,000 U TNF-alpha/injection produced a fraction (20% to 80%) of LTS. The host defense activities examined included those of splenic and thymic cytolytic T lymphocytes (CTL) and lymphokine-activated killer cells as well as splenic tumoricidal macrophages. Although most activities were modulated by tumor growth and/or treatment, only CTL responsiveness appeared to correlate with survival. CTL activity in the treated groups with LTS was significantly higher than in control groups late in the treatment period. Finally, ex vivo analyses of splenocytes and thymocytes together with the rejection of implanted tumor at 17 months established that LTS displayed specific long-term immune memory.

Age Factors↗

PubMed1999

Phosphoinositide 3-kinase lipid products regulate ATP-dependent transport by sister of P-glycoprotein and multidrug resistance associated protein 2 in bile canalicular membrane vesicles.

Bile acid transport and secretion in hepatocytes require phosphatidylinositol (PI) 3-kinase-dependent recruitment of ATP-dependent transporters to the bile canalicular membrane and are accompanied by increased canalicular PI 3-kinase activity. We report here that the lipid products of PI 3-kinase also regulate ATP-dependent transport of taurocholate and dinitrophenyl-glutathione directly in canalicular membranes. ATP-dependent transport of taurocholate and dinitrophenyl-glutathione in isolated canalicular vesicles from rat liver was reduced 50-70% by PI 3-kinase inhibitors, wortmannin, and LY294002, at concentrations that are specific for Type I PI 3-kinase. Inhibition was reversed by addition of lipid products of PI 3-kinase (PI 3,4-bisphosphate and, to a lesser extent, PI 3-phosphate and PI 3,4,5-trisphosphate) but not by PI 4, 5-bisphosphate. A membrane-permeant synthetic 10-mer peptide that binds polyphosphoinositides and leads to activation of PI 3-kinase in macrophages doubled PI 3-kinase activity in canalicular membrane vesicles and enhanced taurocholate and dinitrophenyl-glutathione transport in canalicular membrane vesicles above maximal ATP-dependent transport. The effect of the peptide was blocked by wortmannin and LY294002. PI 3-kinase activity was also necessary for function of the transporters in vivo. ATP-dependent transport of taurocholate and PI 3-kinase activity were reduced in canalicular membrane vesicles isolated from rat liver that had been perfused with taurocholate and wortmannin. PI 3,4-bisphosphate enhanced ATP-dependent transport of taurocholate in these vesicles above control levels. Our results indicate that PI 3-kinase lipid products are necessary in vivo and in vitro for maximal ATP-dependent transport of bile acid and nonbile acid organic anions across the canalicular membrane. Our results demonstrate regulation of membrane ATP binding cassette transporters by PI 3-kinase lipid products.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

The role of phosphoinositide 3-kinase in taurocholate-induced trafficking of ATP-dependent canalicular transporters in rat liver.

Recent studies indicate that wortmannin, a potent inhibitor of phosphatidylinositol (PI) 3-kinase, interferes with bile acid secretion in rat liver; taurocholate induces recruitment of ATP-dependent transporters to the bile canalicular membrane, and PI 3-kinase products are important in intracellular trafficking. We investigated the role of PI 3-kinase in bile acid secretion by studying the in vivo effect of taurocholate, colchicine, and wortmannin on bile acid secretion, kinase activity, and protein levels in canalicular membrane vesicle (CMV) and sinusoidal membrane vesicle (SMV) fractions from rat liver. Treatment of rats or perfusion of isolated liver with taurocholate significantly increased PI 3-kinase activity in both membrane fractions. Taurocholate increased protein content of ATP-dependent transporters, which were detected only in CMVs, whereas increased levels of p85 and a cell adhesion molecule, cCAM 105, were observed in both fractions. Colchicine prevented taurocholate-induced changes in all proteins studied, as well as the increase in PI 3-kinase activity in CMVs, but it resulted in further accumulation of PI 3-kinase activity, p85, and cCAM 105 in SMVs. These results indicate that taurocholate-mediated changes involve a microtubular system. Wortmannin blocked taurocholate-induced bile acid secretion. The effect was more profound when wortmannin was administered prior to treatment with taurocholate. When wortmannin was given after taurocholate, the protein levels of each ATP-dependent transporter were maintained in CMVs, whereas the levels of p85 and cCAM decreased in both membrane fractions. Perfusion of liver with wortmannin before taurocholate administration blocked accumulation of all proteins studied in CMVs and SMVs. These results indicate that PI 3-kinase is required for intracellular trafficking of itself, as well as of ATP-dependent canalicular transporters.

Adenosine Triphosphate↗

PubMed1998

Thymic anti-tumor effectors in mice cured of lymphoma by cyclophosphamide plus TNF-alpha therapy: phenotypic and functional characterization up to 20 months after initial tumor inoculation.

As reported previously, cyclophosphamide plus tumor necrosis factor-alpha treatment of C57BL/6 mice bearing advanced EL4 lymphoma induced approx. 60% long-term (i.e., >60 days) survivors. These mice developed protective immunity, as evidenced by 1) rejection (100% survival) of EL4 tumor re-implanted on day 60 (day 0 = initial tumor implantation); and 2) development of significant levels of specific EL4 tumor cell killing activity by both splenocytes and thymocytes. Using this model, age-related changes in functionally and phenotypically definable thymocyte subsets were assessed. In thymocytes from 90 to 308 day survivors, specific immune memory was long term; both CD4+ and CD8+ cells were required for the ex vivo stimulation of lytic activity, but the specific anti-EL4 cytotoxic effector was CD4-CD8+. On day 520, the surviving mice were randomized into 2 groups. One group received a second re-challenge with EL4 tumor cells and all survived. The other group was sacrificed on day 520. Their thymocytes, exposed to X-irradiated EL4, developed anti-EL4 lytic activity and, in comparison with thymocytes of young and age-matched control mice, were markedly enriched in CD4-CD8+CD44+ cells. On day 625, thymocytes from the survivors of the day 520 re-challenge were evaluated and were found to have developed specific anti-EL4 lytic activity. Phenotypically, they had returned toward the pattern seen in age-matched control mice although CD4-CD8+CD44+ cells remained increased. These mice were > or = 2 years old, the median life span of C57BL/6 mice. Thus, mice cured of tumor by an immuno-modulating regimen rejected re-implanted primary tumor and maintained specific thymic anti-tumor immune memory for life.

Animals↗

PubMed1998

Doxorubicin plus tumor necrosis factor alpha combination treatments in EL4-lymphoma-bearing C57BL/6 mice.

The therapeutic efficacy of a total of 42 single-agent or combination protocols involving doxorubicin (Adriamycin, ADM) and tumor necrosis factor alpha (TNFalpha) were evaluated in the syngeneic murine lymphoma model, C57BL/6-EL4. Combination treatments were the most effective and the therapeutic effects were schedule-dependent; e.g. it was generally advantageous for ADM to precede TNFalpha administration. Two protocols selected for further study were 4 mg/kg ADM i.v. on days 1 and 8 plus TNFalpha, i.v., at either 16000 U (7 microg)/injection, on days 1 and 8 or 4000 U (1.7 microg)/injection, on days 11-15. Survival of mice bearing one of four EL4 sublines having different in vitro drug sensitivities was assessed. These sublines were E10 (ADM-sensitive/TNFalpha-resistant), E16 (sensitive/sensitive), ER2 (ADM-resistant/TNFalpha-sensitive) and ER13 (resistant/resistant). Between 80% and 100% long-term survivors (i.e. tumor free on day 60) were obtained with the two treatments in mice bearing ADM-sensitive sublines, even though one of these sublines, E10, was resistant to TNFalpha in vitro. Induction of long-term survival appeared, therefore, to correlate with in vitro defined sensitivity/resistance to ADM, but not to TNFalpha Treatment-induced modulations of tumoricidal immune effector functions were also examined. Taken together, the results indicated that induction of long-term survival involved complex interactions of: (1) ADM-induced tumor modifications, including, but not limited to, tumor debulking, (2) combination-treatment-induced modifications of splenic cytolytic T cell and macrophage activities, and (3) the restoration of thymus cellularity. Finally, when long-term survivors resulting from treatment of E10- or E16-bearing mice were implanted with ER2 on day 120, the majority survived, indicating that long-term immune memory, capable of recognizing drug resistant variants, had been established.

Animals↗

PubMed1997

Expression of B cell markers on SR-4987 cells derived from murine bone marrow stroma.

The murine cell line SR-4987 was originated in our laboratory from adherent cells of a long term bone marrow culture. SR-4987 cells do not express p21-ras and c-fms products on membrane whereas secrete M-CSF, evidence a fibroblast-like morphology and are vimentine positive. This line shows a very poor "in vitro" agar clonogenicity which is not modulated by the addition of different cytokines and growth factors (M-CSF, GM-CSF, G-CSF, IL-3, IL-7, alpha-TNF, PDGF, and EGF). On the contrary, a dramatic increase in clonogenicity is observed in the presence of bFGF. The RT-PCR investigation evidences the mRNA encoding for bFGF, IL-7, GM-CSF, and SCF (c-kit ligand). The analysis of CD antigen expression on SR-4987 cell membrane indicates a phenotype (CD5+, CD44+, 45R(B220)+, sIg+, 5'-nucleotidase+) that is consistent with a B cell feature. Our observations suggest that exogenous bFGF might represent an appropriate stimulus for inducing the SR-4987 cells proliferation also in the absence of cell-substrate anchorage. Further, they indicate that SR-4987 cells could represent a particular differentiation stage in which characters of "stromal cell" and "B cell" are coexpressed in agreement with the hypothesis of a common stromal-hematopoietic differentiation.

Animals↗

PubMed1996

Evidence for the involvement of ecto-5'-nucleotidase (CD73) in drug resistance.

Increased ecto-5'-nucleotidase (ecto-5'NT) protein expression in several multidrug-resistant (MDR) cell lines, documented previously by our group, suggests that this enzyme is involved in drug resistance. Here, Northern blot analysis of selected cell lines and their MDR variants positively correlated ecto-5'NT protein with its mRNA expression. An inhibitor of ecto-5'NT enzymatic activity, alpha,beta-methyleneadenosine 5'-diphosphate (AMP-CP), was used to determine if functionally active enzyme had a role in drug resistance. AMP-CP (0.3 mM) reversed the resistance of ecto-5'NT-positive MDR cells (MCF7/A6, L1210/A) to doxorubicin, whereas it did not affect the doxorubicin sensitivity of the ecto-5'NT-negative parental cell lines or that of 2 ecto-5'NT-negative MDR cell lines (HL60/VCR and A2780/DX5). Furthermore, AMP-CP increased rhodamine uptake and inhibited rhodamine efflux from ecto-5'NT-positive MDR cells without affecting ecto-5'NT-negative MDR cells. The presence of exogenous adenosine (0.5 microM) circumvented AMP-CP-induced inhibition of rhodamine efflux from EL4/ADM cells. AMP-CP inhibited the growth of the ecto-5'NT-positive L1210/A MDR cells but had no effect on the growth of the parental cell line. Determination of intracellular ATP levels indicated that MDR cells which had increased ecto-5'NT expression also had a lower intracellular ATP level than their parental cells. Our results suggest that, in certain MDR cell lines, ecto-5'NT serves as a required accessory molecule in resistance mediated by ATP-dependent mechanisms and that growth-sustaining nucleosides are provided by this salvage pathway.

5'-Nucleotidase↗

PubMed1996

Specific anti-EL4-lymphoma immunity in mice cured 2 years earlier with doxorubicin and interleukin-2.

This laboratory has reported the conditions for an effective, non-toxic, chemoimmunotherapy utilizing doxorubicin in combination with prolonged administration of interleukin-2 and the identification of the critical role of activated CD8+ T cells in the therapeutic effect. Mice (C57BL/6) cured in those studies have been followed for the remainder of their life spans. These mice, approximately 2 months of age when initially inoculated with syngeneic EL4 lymphoma, survived for more than 2 years, the normal life span of C57BL/6 mice. Mice 4 months old reinoculated with the EL4 cells all survived. At about 1 year of age mice were sacrificed and the ability of their thymocytes and splenocytes to develop specific CD8+ anti-EL4 activity was as high as it had been at the time of tumor rejection. At about 2 years of age EL4 was reimplanted into mice; all of them survived. These surviving mice, at 2 years 2 months of age, as well as a group of 2-year-old mice not rechallenged, were killed and functional antitumor activity and phenotype characteristics of various lymphocyte populations were determined in comparison to those of young and age-matched control mice. The phenotyping of the lymphocytes from the cured mice indicated very notable differences in subset distribution and increased CD44 expression. Functionally they developed high levels of anti-EL4 activity, which was ablated by combined treatment with monoclonal antibodies against CD8 and CD44, indicating the role of memory cells. Consistent with cells from aged mice, these same cell populations had a very reduced allogeneic responsiveness. It appears that cured mice have developed an immune memory specific for EL4.

Animals↗

PubMed1995

Cyclophosphamide plus tumor necrosis factor-alpha chemoimmunotherapy cured mice: life-long immunity and rejection of re-implanted primary lymphoma.

Changes in functionally and phenotypically definable splenocyte subsets in aging mice which had been rendered tumor-free in early life by immunochemotherapy (cyclophosphamide plus tumor necrosis factor-alpha) were studied in the syngeneic EL4 lymphoma-C57BL/6 murine model. Treatment-induced long-term survivors (LTS) surviving rechallenge are termed "immune-LTS". On day 120 (day 0, initial tumor inoculation), splenocytes from day 60 rechallenged immune-LTS developed significantly greater specific anti-EL4 cytolytic activity in an ex vitro assay than those from non-rechallenged LTS. Splenocytes from combination-treated groups developed significantly higher activity than those from cyclophosphamide-induced immune-LTS. The splenic effector precursor was a CD8+ T cell. The specific anti-EL4 effector cell from the cyclophosphamide-induced immune-LTS was CD4- CD8+; however, approximately 50% of those from combination-treated immune-LTS appeared to be CD4+CD8+. On day 520 immune-LTS were randomized into 2 groups. One group was re-implanted with EL4 tumor; all mice survived. The other group was killed and, even though their splenocytes developed considerable anti-EL4 activity, their allogeneic responsiveness was as reduced as that of age-matched controls. Phenotypic analysis, compared with splenocytes from young and age-matched controls, revealed changes in the makeup of each T-cell subset, except the CD4+CD8+, and all subsets, except the CD4-CD8-, had increases in CD44 positivity. On day 625, the age of these mice was equivalent to the median life-span of C57BL/6 mice; nevertheless, their splenocytes developed high anti-EL4 activity. Phenotypic analysis indicated that, compared to day 520, there was a major decrease in CD4-CD8+ splenocytes; we suggest that these cells had migrated to the site of tumor eradication.

Animals↗

PubMed1995

Protective specific immunity induced by cyclophosphamide plus tumor necrosis factor alpha combination treatment of EL4-lymphoma-bearing C57BL/6 mice.

A combination treatment protocol initiated 12 days after tumor injection, when the tumor was large, by administering cyclophosphamide (CY, 150 or 250 mg/kg) intraperitoneally followed by intravenous tumor necrosis factor alpha (TNF alpha, 1000 units injection) on days 13, 16, 18, 21, and 23, resulted in about 60% long-term survival (i.e., survival for at least 60 days) in the syngeneic C57BL/6 mouse/EL4 lymphoma model system. The establishment of a specific antitumor immune memory and its possible therapeutic relevance was verified by reinjecting 60-day survivors with EL4 cells; all 60-day survivors that had received the combination treatments rejected the implants and survived for a further 60 days. Thymic cellularity was reduced during treatment and its recovery appeared to correlate with long-term survival and immunity. Thymocytes from mice treated with the combination were found to express significant levels of specific anti-EL4 cytolytic activity following a 4-day stimulation culture with X-irradiated EL4 cells and low concentrations of interleukin-2. This response could not be generated with thymocytes from naive animals. In each case the effect seen with the combination of a moderate CY dose (150 mg/kg) with TNF alpha was better than that seen with either dose of CY alone and equal to or better than that seen with the higher dose of CY combined with TNF alpha. These results indicate that treatment with a single moderate dose of CY in combination with TNF alpha is effective against a large, established tumor in this murine model. Furthermore, all the long-term survivors induced by this treatment developed protective immunity against reimplanted tumor and demonstrated a long-term specific immune memory in the thymus.

Adjuvants, Immunologic↗

PubMed1994

Ecto-5'-nucleotidase (CD73) in multidrug-resistant cell lines generated by doxorubicin.

Cytochemical screening for a panel of enzymes revealed increased 5' nucleotidase (5'NT) expression in 3 of 3 P-glycoprotein 170 (Pgp170)-positive multidrug-resistant (MDR) variants of the murine EL4 T-lymphoma cell line (EL4/ADM, ER2 and ER13). Electron microscopic localization established the presence of the membrane-bound ecto-form of the enzyme. Nine other murine, human and Chinese hamster cell lines and their MDR variants were tested for ecto-5'NT. Of these, 4 MDR variants (human cell lines MCF7A6, MCF7A2, HeLaJ2C and the murine cell line L1210A) showed increased expression of ecto-5'NT, when compared with their parental cell lines. The findings with cells of human origin were confirmed by immunofluorescent localization with a specific monoclonal antibody (MAb) (27.2) against the human ecto-5'NT. All MDR cell lines with elevated ecto-5'NT expression were generated by doxorubicin treatment. These cells were more sensitive than their parental cell lines to AMP at concentrations of 1.5-3.0 mM, confirming that the expressed ecto-5'NT was biologically active. The parental and MDR cells did not differ, in general, in their sensitivity to adenosine. An inhibitor of ecto-5'NT, alpha,beta-methyleneadenosine 5'-diphosphate, completely reversed the resistance of the EL4/ADM cell line to doxorubicin. The possibility exists of a functional relationship between the ecto-5'NT molecule and the members of the ATP-binding cassette transporter superfamily, important components of MDR, in some cell types.

5'-Nucleotidase↗

PubMed1994

Intracellular doxorubicin kinetics in lymphoma cells and lymphocytes infiltrating the tumor area in vivo: a flow cytometric study.

Recently we have reported the development of a safe and effective chemoimmunotherapy protocol involving doxorubicin (Dox) in combination with interleukin 2 which, in C57BL/6 mice, boosts local T cell responses, and, in 50 to 80% of the cases, this resulted in the complete eradication of established syngeneic EL4 lymphoma or its Dox-resistant variant, EL4/A. Accumulation of host-derived leukocytes in the peritoneal cavity was increased up to 8-fold after tumor inoculation, but, in absolute numbers, did not increase further following Dox administration. The cellular pharmacokinetic studies undertaken to clarify the role of Dox following a single IV injection indicate that 4 h later, lymphocytes found in the peritoneal cavity have detectable levels of Dox; but the lymphoma cells (both EL4 and EL4/A) have, in proportion to their larger size, taken up more drug as judged by flow cytometry. The estimated drug "concentration" (i.e., intracellular amount divided by estimated cell size) at the 4-h time point, however, was found to be essentially equivalent in both the lymphoma cells and the lymphocytes. Thereafter, the drug content and intracellular "concentration" in the EL4/A cells rapidly declined while their numbers progressively increased. In contrast, the EL4 lymphoma cells and the lymphocytes found in the peritoneal cavity in the presence of either lymphoma consistently exhibited higher levels of drug 24-48 h than at 4 h. Splenic and tumor-infiltrating mature T (CD3+) cells were completely insensitive to Dox cytotoxicity and actually showed increased CTL activity when examined ex vivo. Although EL4 cells had identical Dox uptake patterns to those of CD3+ cells, they were sensitive to the drug and their numbers decreased, resulting in increased host/tumor cell ratios in these mice. The pharmacokinetic parameters of the drug and the insensitivity of the mature T cells to the drug determined in this study can explain, in part, the efficacy of a chemoimmunotherapy protocol boosting local T-cell responses.

Animals↗

PubMed1994

TNF-alpha potentiation of the lymphokine-activated killer response of murine thymus cells.

The role of tumor necrosis factor (TNF-alpha) on in vitro generation of lymphokine-activated killer (LAK) cells from murine thymocytes was investigated and compared to that on generation of LAK from splenocytes. TNF-alpha increased the potential of interleukin-2 (IL-2) at suboptimal concentrations to generate LAK activity in thymocytes even more than in splenocytes. In parallel, augmented [3H]thymidine uptake by thymocytes and splenocytes was seen. However, no net increase in viable cell number was observed. LAK effector cells from TNF-alpha plus IL-2 cultures responded with an increased [3H]thymidine uptake to restimulation by IL-2 alone. These results suggest that TNF-alpha + IL-2 may be inducing the expansion of a small subset of cells. NK1.1+ cells are a very minor subset of thymocytes, nevertheless phenotype analysis showed that in thymocytes, IL-2 + TNF-alpha generates NK1.1+ CD8- LAK effectors in contrast to NK1.1- CD8+ cells found with IL-2 alone. This result is consistent with the finding in the proliferation studies. The fact that thymocytes are stimulated by the TNF-alpha + IL-2 combination to proliferate as well as to develop a phenotypically distinct effector supports the role of TNF-alpha in intra- and extrathymic regulation.

Animals↗

PubMed1993

Immunological responses critical to the therapeutic effects of adriamycin plus interleukin 2 in C57BL/6 mice bearing syngeneic EL4 lymphoma.

A safe and effective therapeutic combination of moderate doses of Adriamycin (doxorubicin, 4 mg/kg, IV, Days 1 and 8 or only Day 8) plus prolonged administration of moderate doses of interleukin 2 (2 micrograms, b.i.d., Days 9-40) was developed in the syngeneic EL4 (5 x 10(4) cells, IP, Day 0) lymphoma--C57B1/6 mouse model and has been reported in the companion paper. The studies described herein demonstrate that the effectiveness of this combination treatment against EL4 lymphoma growing intraperitoneally in C57B1/6 mice was dependent upon the presence of CD8+ cells. Thus, the induction of long-term survivors (60-80%) by Adriamycin plus interleukin 2 was completely ablated by pretreatment of mice with anti-CD8 monoclonal antibody (MAb), whereas pretreatment with anti-CD4 MAb only partially inhibited the therapeutic effects and anti-NK1.1 MAb had no effect. A close association between survival, an increase in phenotypically identified CD8+ cells, and an increase in specific anti-EL4 cytolytic activity was demonstrated with cells from the tumor site (peritoneum) but not consistently with cells from the spleen. No association was observed between survival and modulations in natural killer (NK), lymphokine-activated killer (LAK), or tumoricidal macrophage activity of spleen or peritoneal cells. Taken together the results indicate that, in this model, the most relevant correlate of a therapeutically effective host antitumor response is the level of specific EL4 tumor killing by cells present at the tumor site. Based on the findings reported herein, it can be predicted that weakly immunogenic tumors may be eradicated by immunologic mechanisms elicited in conjunction with properly designed therapeutic regimens.

Adjuvants, Immunologic↗

PubMed1991

NK-cell activity affected by some cytostatic drugs and their additives.

The direct effect of selected cytostatic drugs on natural killer (NK) cell activity was evaluated. Peripheral blood mononuclear cells from healthy donors were tested for their cytolytic activity in vitro in the presence of adriamycin, methotrexate, leucovorin, vincristin, cytosine arabinoside and teniposide. Most of the tested cytostatic drugs did not show to be active at concentrations comparable to their plasma level. However, diluents of some preparations (cytosine arabinoside, teniposide) containing organic solutions and stabilizing additives (e.g. benzyl alcohol) suppressed the NK activity more than chemotherapeutic agents alone. Thus teniposide, containing such additives, inhibited NK activity already at 5 mg/ml, while its peak plasma concentration was 23.8 mg/ml. The inhibitory concentrations of teniposide did not affect the target binding of effector cells and the expression of 14 tested leukocyte differentiation markers. This implies that a postbinding step of the lytic process was altered by the preparation. Likewise, no inhibition of lectin dependent cellular cytotoxicity by teniposide and its diluent was observed, suggesting that the lectin may substitute the missing lytic signal.

Antigens, Differentiation↗

PubMed1990

Purine metabolism enzymes and immunological phenotype in chronic B-cell malignancies: chronic lymphocytic leukemia, prolymphocytic leukemia and hairy cell leukemia.

The chronic lymphocytic leukemia, the prolymphocytic leukemia and the hairy cell leukemia of B-cell immunophenotype are closely related disorders, but differ in their cytomorphological and clinical features. In an attempt to differentiate further among these forms of leukemia some immunological and cytochemical markers were studied. Simultaneously we measured adenosine deaminase and purine nucleosidephosphorylase activities by a method of paper radiochromatography in peripheral blood/bone marrow leukemic cells from 23 patients with chronic lymphocytic leukemia, 5 patients with prolymphocytic leukemia, one with prolymphocytoid transformation of chronic lymphocytic leukemia and 15 patients with hairy cell leukemia. The mosaic of immunological and cytochemical markers based on the sum of positive and negative features allowed for the correct diagnosis in a majority of cases. From the number of 43 investigated cases we found the typical enzyme patterns in 39 of them. On the basis of purine enzyme activity we were able to differentiate between chronic lymphocytic leukemia versus prolymphocytic and hairy cell leukemia. In one patient with chronic lymphocytic leukemia we could detect very early stage of prolymphocytoid transformation by increased activity of purine nucleosidephosphorylase activity. There were only two patients with chronic lymphocytic leukemia who were assigned to the prolymphocytic leukemia on the basis of purine nucleosidephosphorylase activity and two patients with hairy cell leukemia with atypical enzyme pattern attributable to the nonrepresentative number of pathological cells in the peripheral blood. Our study showed that purine nucleosidephosphorylase activity in leukemia cells may be useful as an additional parameter in the distinction of prolymphocytic from lymphocytic leukemia and that it may represent an enzymatic marker for early detection of prolymphocytoid transformation of chronic lymphocytic leukemia. Characteristic purine enzyme pattern was found also for diagnostic confirmation of hairy cell leukemia.

Adenosine Deaminase↗

PubMed1990

Clinical significance of standard CD assessment in acute leukemia.

The data of detailed studies of immunophenotype of blast cells in 426 patients with acute leukemias are presented. Diagnostic and prognostic significance of different marker expression has been evaluated in groups of patients with ALL and AML. Frequency distribution of T1, T2, T3, pre-B, B, common, Ia and null subvariants identified according to immunoclassification of Baryshinkov et al. was studied in 250 children with ALL. These subvariants differed both in duration of disease (p = 0.0015) and in duration of first complete remission (p = 0.0031). The use of monoclonal antibodies of VI-series in 90 patients with ALL allowed to describe an immunophenotype of the subvariants in detail. The mosaic expression of myeloid antigens CD11, CD14, CD15, CDw65 identified by MoAbs VIM-12, VIM-13, VIM-D5 and VIM-2, respectively, on blast cells of patients with AML was shown. The expression of CD11 (ICO-GM1) or CD15 (ICO-G2) was prognostically unfavorable in children with AML (p = 0.0028). The expression of T-cell markers (E-receptor, CD7, reactivity with anti-T-cell serum) on blasts was prognostically favorable in children with AML (p = 0.003). So the data of immunophenotyping are of great value for accurate diagnosis and prognosis of acute leukemias.

Antibodies, Monoclonal↗

PubMed1988

Diagnosis and analysis of the clinical course of T-phenotype acute lymphoblastic leukemia.

We refer to the diagnostic possibilities in T-phenotype acute lymphoblastic leukemia. Immunophenotyping based on the proof of T-differentiation antigens by means of specific monoclonal antibodies and assessment of the E receptor, as well as examination of enzymatic activities of adenosine deaminase and purinenucleoside phosphorylase, were performed. Thirty patients with acute lymphoblastic leukemia of T-phenotype were examined. The monoclonal antibodies used demonstrated a heterogeneity in this type of leukemia reflecting the stage of thymocyte differentiation. The cells of some patients with T-phenotype acute lymphoblastic leukemia expressed simultaneously the common acute lymphoblastic leukemia antigen and Ia molecules. Examination of enzyme activities demonstrated a characteristic pattern with a significantly increased adenosine deaminase activity and simultaneously decreased purinenucleoside phosphorylase activity in T-phenotype acute lymphoblastic leukemia. The unfavorable course of disease in patients with T-phenotype acute lymphoblastic leukemia was demonstrated analyzing a group of 50 children with acute lymphoblastic leukemia. By means of statistical methods the cumulative rate of children surviving with acute lymphoblastic leukemia of common and T-phenotypes have been expressed. The results showed the need for a more effective treatment aimed at the T-phenotype of acute lymphoblastic leukemia.

Adenosine Deaminase↗