Monoclonal antibodies against human granulocytes and myeloid differentiation antigens

Monoclonal antibodies (MCA) were obtained by immunizing BALB/c mice with 99% pure granulocytes from normal donors or with a whole leukocyte suspension obtained from a chronic myelogenous leukemia (CML) patient, and then fusing the mouse spleen cells with a 315–43 myeloma cell clone. Four MCA were selected and studied using ELISA, immunofluorescence, cytotoxicity assays, and FACS analysis. Antibodies 80H.1. 80H.3. and 80H.5 (from normals) and 81H.1 (from CML) detected antigens expressed on neutrophils. Antibodies 80H.1 and 80H.3 (lgG) also reacted with monocytes but not with other blood cell subsets. Antibodies 80H.5 and 81H.1 (lgM) were cytotoxic and reacted strongly with most of the cells of the neutrophil maturation sequence. i.e., myeloblasts, promyelocytes, myelocytes, and mature granulocytes. Antibodies 80H.5 and 81H.1 also inhibited BFU-GM and CFU-E. Antigens recognized by 80H.3. 80H.5, and 81H.1 were expressed both on a proportion of cells from HL.60, KG.1, ML.1, and K562 myeloid cell lines, and on a proportion of blast cells isolated from patients with acute myelogenous leukemia. They were not found on lymphoid cell lines or lymphoid leukemia cells. These MCA recognize either late differentiation antigens expressed on mature neutrophils and monocytes (80H.1 and 80H.3) or early differentiation antigens (80H.5 and 81H.1) specific to the granulocytic lineage. They may be useful for a better definition of those antigens specific to hematopoietic stem cells and their relationship with normal or neoplastic hematopoiesis.     

鸡血藤活性成分SS8对骨髓抑制小鼠造血祖细胞增殖的作用

目的:研究鸡血藤单体成分SS8对骨髓抑制小鼠造血祖细胞(CFU-GM,CFU-E,BFU-E,CFU-Meg)增殖的影响。方法:采用甲基纤维素半固体培养法,通过对长期接受SS8治疗后的骨髓抑制小鼠造血祖细胞的培养,观察SS8对CFU-GM,CFU-E,BFU-E,CFU-Meg生长的作用。结果:SS8可显著刺激骨髓抑制小鼠CFU-GM,CFU-E,BFU-E,CFU-Meg生长,与对照组比较有显著差异(P<0.05)。随时间延长、剂量增加,刺激作用逐渐加强。结论:SS8对骨髓抑制小鼠造血祖细胞的增殖有明显刺激作用,且有时间、剂量相关性。     

Disparate lympho-erythroid donor to recipient chimaerism in a β°-thalassaemia bone marrow transplant recipient with red cell indices indicative of apparent full engraftment

A 4-year-old girl with transfusion-dependent β°-thalassaemia received an HLA-identical bone marrow transplant (BMT) from her β°-thalassaemia trait sister. Prior to BMT, chromosomal analysis revealed the recipient to have 46,XX,9qh+, a polymorphic variant of the heterochromatin region of chromosome 9, which her donor did not have. Within 1 month post-BMT, 89% of nucleated bone marrow cells were of donor origin. One year later, donor engraftment had decreased to 44% and 34% in nucleated bone marrow cells and blood lymphocytes, respectively. By 2 years, donor lymphocyte engraftment fell to 5%, raising concern of possible graft rejection. To examine erythroid chimaerism, globin synthesis by individual erythroid progenitor cell derived colonies (BFU-E) was analysed. On days 1000 and 1130 post-BMT, 79% and 77% of colonies, respectively, synthesized β-globin and therefore were of donor origin.     

Effect of cimetidine on burst-promoting activity of normal T lymphocytes

Summary The effect of cimetidine, an inhibitor of suppressor T lymphocytes, on the burst-promiting activity (BPA) of normal T lymphocytes has been studied. Cimetidine has been shown to increase the BPA of normal T lymphocytes, both when added to the culture and when T lymphocytes were preincubated for 1 h with it. Cimetidine had no direct effect on the in vitro growth of burstforming units (BFU-E). Our results show that CD 8 suppressor T lymphocytes inhibit the in vitro growth of BFU-E in normal conditions, either directly or through inhibition of BPA of CD 4 helper T lymphocytes. Cimetidine has proved to be a useful tool for investigating the hematological role of T-lymphocyte subsets in normal and pathological conditions.This work was supported by a grant of theMinistem delta Ricerca Scientifica e Tecnologica, Italy     

In vitro study on cryopreservation of peripheral blood stem cells with uncontrolled freezer

Objective: To evaluate the effects of cryopreservation of APBSCs in -80℃ un-controlled freezer and liquid nitrogen, and to search for the efficient combined cryoprotectant and the highest cell concentration for cryopreservating peripheral blood stem cell (PBSC). Methods: To compare the effect of three combined cryoprotectants, evaluation of in vitro proliferative capacity by colony-forming unit- Granulocyte-macrophage (CFU-GM) and burst-forming Unit-erythroid (BFU-E) assay, immunophenotyping for CD34+/CD38- cells by FCM, and viability assessment by trypan blue exclusion were performed. Results: The cryoprotectant 10%DMSO+HES+auto-Plasma resulted in the highest recovery rates. CFU-GM and BFU-E were (78.7&#177;9.8)%, (69.8&#177;14.1)%, respectively. The recovery rates of CFU-GM and BFU-E in A/Cgroups were (68.3&#177;6.2)%/ (65.8&#177;7.2)% and (63.4&#177;9.7)%/ (60.4&#177;10.5)%, respectively. The recovery rates of CD34+/CD38- cells and cell viability with the three combined reagents were 90% and 80%, respectively. Conclusion: 5%DMSO+ HES+auto-PLASMA is an ideal combined cryoprotectant for cryopreserving PBSC. The cell concentrations may be cryopreserved at 4&#215;108 m1-1.     

Kinetics of colony formation by BFU-E grown under different culture conditions in vitro

Colony formation by erythroid burst-forming units (BFU-E) involves a variable number of cell divisions before individual 'subcolonies' begin to appear. Consequently the numbers of subcolonies vary amongst individual bursts. If this observation is interpreted as a reflection of a stochastic process, the number of subcolonies in each individual burst represents the number of divisions by the BFU-E prior to commitment to terminal differentiation. This provides a means for quantitating the probability of erythroid differentiation (pD) and the probability of renewal (1 − pD). In order to determine whether these kinetics of burst formation can be influenced by exogenous factors we used three commercially available media designed for the growth of BFU-E. We found that subcolony numbers per burst ranged from one to 64 and that the cumulative distributions of subcolonies per burst followed a logarithmic curve ( r   > 0.90). Differences were observed in the distribution of subcolonies per burst when BFU-E were grown in different media (  P  = 0.03; Kruskall-Wallis test). The probability of immediate terminal differentiation (i.e. committment to form a subcolony) was 0.25 for two of the media and 0.7 for the third. The corresponding renewal probabilities were 0.75 and 0.3. These data indicate that the proliferation kinetics of BFU-E are susceptible to regulation by exogenous factors.     

Uncaria tomentosa stimulates the proliferation of myeloid progenitor cells

Ethnopharmacological relevance

The Asháninkas, indigenous people of Peru, use cat's claw (Uncaria tomentosa) to restore health. Uncaria tomentosa has antioxidant activity and works as an agent to repair DNA damage. It causes different effects on cell proliferation depending on the cell type involved; specifically, it can stimulate the proliferation of myeloid progenitors and cause apoptosis of neoplastic cells. Neutropenia is the most common collateral effect of chemotherapy. For patients undergoing cancer treatment, the administration of a drug that stimulates the proliferation of healthy hematopoietic tissue cells is very desirable.It is important to assess the acute effects of Uncaria tomentosa on granulocyte-macrophage colony-forming cells (CFU-GM) and in the recovery of neutrophils after chemotherapy-induced neutropenia, by establishing the correlation with filgrastim (rhG-CSF) treatment to evaluate its possible use in clinical oncology.

Materials and methods

The in vivo assay was performed in ifosfamide-treated mice receiving oral doses of 5 and 15 mg of Uncaria tomentosa and intraperitoneal doses of 3 and 9 μg of filgrastim, respectively, for four days. Colony-forming cell (CFC) assays were performed with human hematopoietic stem/precursor cells (hHSPCs) obtained from umbilical cord blood (UCB).

Results

Bioassays showed that treatment with Uncaria tomentosa significantly increased the neutrophil count, and a potency of 85.2% was calculated in relation to filgrastim at the corresponding doses tested. An in vitro CFC assay showed an increase in CFU-GM size and mixed colonies (CFU-GEMM) size at the final concentrations of 100 and 200 μg extract/mL.

Conclusions

At the tested doses, Uncaria tomentosa had a positive effect on myeloid progenitor number and is promising for use with chemotherapy to minimize the adverse effects of this treatment. These results support the belief of the Asháninkas, who have classified Uncaria tomentosa as a ‘powerful plant’.     

Quiescent CD34+ early erythroid progenitors are resistant to several erythropoietic 'inhibitory' cytokines; role of FLIP

In this study, quiescent bone marrow-derived CD34+ erythroid burst-forming units (BFU-E) were found to be resistant to the inhibitory effects of tumour necrosis factor (TNF)-alpha and -beta as well as interferon (IFN)-alpha, -beta and -gamma, in contrast to those stimulated by a combination of erytrhropoietin (Epo) plus kit ligand (KL). Unexpectedly, we found that TNF-alpha also inhibited the apoptosis of quiescent normal human CD34+ BFU-E cells. Accordingly, TNF-alpha added to CD34+ cells cultured for 2 d in serum-free medium protected clonogeneic BFU-E from undergoing serum deprivation-mediated apoptosis. Furthermore, the prosurvival effect of TNF-alpha in quiescent CD34+ cells was consistent with its ability to induce phosphorylation of mitogen-activated protein kinase (MAPK) p42/44. However, when added to CD34+ cells that were stimulated by Epo + KL, TNF-alpha induced apoptosis and inhibited proliferation of BFU-E. To explain this intriguing differential sensitivity between unstimulated CD34+ cells versus those stimulated by Epo + KL, we examined the expression of apoptosis-regulating genes (FLIP, BCL-2, BCL-XL, BAD and BAX) in these cells. Of all the genes tested, FLIP became rapidly downregulated in CD34+ cells 24 h after stimulation with Epo + KL, suggesting that it may protect quiescent CD34+ BFU-E progenitors residing in the bone marrow from the inhibitory effects of inflammatory cytokines. Thus, we hypothesize that cycling cells may become more sensitive to proapoptotic stimuli (e.g. chemotherapy, inhibitory cytokines) than quiescent ones because of the downregulation of protective FLIP.     

Impaired production of burst promoting activity by blood mononuclear cells from chronic uremic patients

The ability of blood mononuclear cells (MNC) to produce burst promoting activity (BPA) was evaluated in 31 patients with chronic renal failure. The BPA of cells from uremic patients, with or without hemodialysis, was consistently lower than that of 17 normal donors (mean 64%, P less than 0.01). Coculture of MNC with recombinant erythropoietin (rEpo) in vitro did not increase BPA production. Five of 31 patients received in vivo treatment with rEpo (1,500 units x3/week) and showed therapeutic benefit, but in all patients the BPA production remained low. On the other hand, in four patients who were on a hemodialysis protocol and subsequently underwent renal transplantation, impaired BPA production was resolved quickly, and at the same time the number of circulating BFU-E and the hemoglobin level increased toward normal ranges. Furthermore, such impaired BPA production was not observed in patients receiving continuous ambulatory peritoneal dialysis. These observations suggest that decreased production of BPA may play a role in the development of anemia associated with chronic uremic patients, and the correction of BPA production by the improvement of hemodialysis procedure may result in more effective therapy with rEpo for those patients.     

Effects of thymocytes on marrow cells from normal and busulfan-treated mice

To study the effects of thymocytes on hemopoiesis, we 1) cocultured marrow cells with and without thymocytes in an erythroid burst (BFU-E) culture system, 2) injected marrow cells with and without thymocytes into supralethally irradiated mice to assay CFU-S, and 3) assessed the survival of supralethally irradiated mice transplanted with marrow cells with or without thymocytes. The marrow cells used were either from mice given six injections of busulfan and then permitted to rest for 2, 5, or 10 weeks or from mice treated similarly with the busulfan vehicle alone. Thymocytes did not alter spleen surface colony counts or survivorship in any of the test groups. Thymocytes did effect an increase in BFU-E cultured from marrow obtained from the vehicle-treated mice but not from marrow of busulfan-treated mice. Thus, in addition to decreasing the population of hemopoietic precursors in the marrow, busulfan alters the nature of the remaining early erythroid precursor cell population rendering it unresponsive to thymocytes in vitro.