Biomedical subjects

C Caux

Publications and source records attributed to C Caux.

At least 73 records · Page 4Linked to original sources

PubMed1994

Long term in vitro growth of lymphoblastoid cells in the dog.

Attempts to grow in vitro cells from canine lymphoid organs led to observation of the occurrence of a spontaneous, delayed and transitory growth of cells in suspension in two lymphoma cultures (out of 20) but also from one (out of 20) dog with unrelated disorder. These cells, with a lymphoblastoid cytological appearance, lack detectable immunoglobulins in cases studied originating from lymphomatous dogs, and have a pseudodiploid canine karyotype. Neither appearing fully immortalized nor showing any tumorigenicity in nude mice or immunosuppressed newborn rats, these may be of lymphoblastoid nature, rather than arising from some tumorous cells. The mechanisms that have triggered the cell growth are still unknown, but such cells could remind of human lymphoblastoid cells, associated with lymphotrophic viruses, still unknown in the dog.

Animals↗

PubMed1994

Interleukin 10 inhibits T cell alloreaction induced by human dendritic cells.

Human dendritic cells (DC) generated from CD34+ hematopoietic progenitors cultured in the presence of granulocyte macrophage colony stimulating factor (GM-CSF) and tumor necrosis factor (TNF)-alpha are related to Langerhans cells (DLC) and have been shown to induce a strong proliferation of allogeneic CD4+ T cells. The present study shows that recombinant human IL-10 (h-IL-10) inhibits the primary and secondary proliferative responses of both CD4+ and CD8+ T cells induced by allogeneic CD1a+ DLC. The alloreaction induced by DLC generated after 5-18 days of culture of CD34+ HPC was equally inhibited by h-IL-10, thus indicating that DLC were sensitive to h-IL-10 at all stages of differentiation. This is further indicated by the h-IL-10-induced inhibition of the T cell alloreaction mediated by interdigitating DC freshly isolated from tonsils. h-IL-10 specifically acted on DLC as it did not affect the proliferation induced by Epstein-Barr virus lymphoblastoid cell lines (EBV-LCL) nor that induced by immobilized anti-CD3. The inhibitory effect of h-IL-10 was not due to the production of suppressive factors by the DLC, as the addition of DLC and IL-10 did not inhibit EBV-LCL-induced T cell proliferation. Rather, the inhibition of cytokine production (IL-2, GM-CSF, TNF, IFN-gamma) observed after 24 h of co-culture may explain the inhibition of T cell DNA synthesis detected 3 days later. The h-IL-10-induced inhibition of human DC mediated alloreaction advocates considering the use of h-IL-10 in the prevention of transplant rejection and graft versus host disease, phenomena initiated by DC.

Antigen Presentation↗

PubMed1993

Myofibroblastic stromal cells isolated from human bone marrow induce the proliferation of both early myeloid and B-lymphoid cells.

Normal human bone marrow stromal cells (BMSC) were isolated from Dexter-type long-term cultures according to their capacity to adhere to plastic and to their lack of hematopoietic antigens. The BMSC displayed a homogeneous appearance and a myofibroblastic phenotype in culture. The stromal cells (SC) were shown to support the proliferation of purified CD34+ hematopoietic progenitors and permitted us to maintain myeloid cells for several weeks in culture. In addition, the BMSC induced the proliferation of purified CD10+ s mu- fetal BM B-cell precursors (BCP). The capacity of the BMSC to induce the proliferation of early myeloid cells was shared by several other human fibroblastic-like cell types. In contrast, the BMSC were far superior to other adherent cells for induction of BCP proliferation. This capacity was largely mediated by endogenously produced interleukin-7 (IL-7), because it could be inhibited by anti-IL-7 antibody. In line with this finding, addition of IL-7 considerably enhanced BCP proliferation in cocultures with skin fibroblasts or synoviocytes. Thus, production of IL-7 appears to be a critical parameter that determines the ability of fibroblastic-like cells to induce BCP proliferation. Taken together, our data show that normal human myofibroblastic BMSC induce the proliferation of both early myeloid and B-lymphoid cells in the absence of accessory hematopoietic cells. The present system should constitute a model to study interactions between native human BM myofibroblastic stroma and various hematopoietic cell subsets.

Antigens, CD↗

PubMed1993

Expression and factor-dependent modulation of the interleukin-3 receptor subunits on human hematopoietic cells.

Interleukin-3 (IL-3) regulates growth and differentiation of multipotential as well as lineage-committed progenitor cells. The human IL-3 receptor (IL-3R) consists of the alpha and common beta (beta c) subunits. The alpha subunit (IL-3R alpha) is specific for IL-3 and binds IL-3 with low affinity. In contrast, the beta c subunit does not bind any cytokine by itself, but forms a high-affinity receptor with IL-3R alpha. As the same beta c subunit also forms high-affinity receptors for IL-5 and granulocyte-macrophage colony-stimulating factor (GM-CSF) with the respective cytokine-specific alpha subunit, the expression of the alpha subunits is responsible for specificity of cytokines. To examine the expression of IL-3R alpha, we have developed a monoclonal antibody (MoAb), N3A. N3A specifically bound to cells expressing IL-3R alpha and immunoprecipitated a 75 Kd glycoprotein, which became 43 Kd on N-glycosidase digestion. N3A and an anti-beta c antibody, CRS1, were used in double color fluorescence-activated cell sorter (FACS) staining with several lineage markers to see the IL-3R expression pattern in peripheral blood (PB), cord blood (CB), and bone marrow (BM) cells. Both IL-3R subunits were expressed on myeloid cell lineages (CD13+, CD14+, CD15Lo, or CD33+). To further study the IL-3R expression on hematopoietic progenitor cells, the CD34+ populations were isolated from both BM and CB cells. Those populations showed positive staining profiles with the N3A MoAb and were weakly stained with the CRS1 MoAb. Furthermore, anti c-kit antibody staining of the CD34+ fraction from CB, but not from BM, showed two intensities and the IL-3R alpha expression seemed to be higher in a fraction of low c-kit expression. Because IL-1, IL-6, G-CSF, stem cell factor (SCF), interferon (IFN)-gamma, and tumor necrosis factor (TNF)-alpha are known to enhance IL-3-dependent colony formation, we have examined whether this enhancement could be correlated with upregulation of the IL-3R expression. Incubation of CD34+ cells with TNF-alpha for 2 days significantly increased the level of beta c and G-CSF increased the number of cells with high level expression of alpha, while other factors did not affect the IL-3R expression. Thus, different cytokines appear to have different mechanisms for enhancement of IL-3-dependent proliferation.

Antibodies, Monoclonal↗

PubMed1993

Tumor necrosis factor alpha cooperates with interleukin 3 in the recruitment of a primitive subset of human CD34+ progenitors.

We have recently demonstrated that tumor necrosis factor alpha (TNF-alpha) potentiates interleukin 3 (IL-3) and granulocyte/macrophage colony-stimulating factor-induced growth of CD34+ hematopoietic progenitor cells (HPC), and favors the generation of dendritic/Langerhans cells. The stimulatory effect of TNF-alpha was detailed in the present study. Thus, CD34+ HPC entering in cycle (S/G2M) after a 48-h pulse with IL-3 expressed the transferrin receptor (TfR), and fluorescence-activated cell sorter-separated TfR+ HPC, but not TfR-HPC, showed a high proliferative response to IL-3. In contrast, TfR-HPC were found to undergo strong proliferation in response to IL-3 + TNF-alpha. Limiting dilution experiments indicated that TNF-alpha increased both the frequency and the average size of clones generated from TfR-HPC as a result of the development of a higher number of large clones. In contrast, TNF-alpha did not enhance the IL-3-dependent proliferation of TfR+ HPC. Preculturing CD34+ HPC for 48 h with TNF-alpha enhanced the subsequent generation of IL-3-dependent colony-forming units. Precultures with TNF-alpha or cultures with suboptimal doses of TNF-alpha allowed the recruitment of cells with both granulocytic and monocytic differentiation potential. Taken together, our results indicate that TNF-alpha recruits a subpopulation of CD34+ HPC hyposensitive to IL-3, with high proliferative capacity and some features of multipotential progenitors, that are likely to be more primitive than those responding to IL-3 alone.

Antigens, CD↗

PubMed1992

GM-CSF and TNF-alpha cooperate in the generation of dendritic Langerhans cells.

Dendritic cells comprise a system of highly efficient antigen-presenting cells which initiate immune responses such as the sensitization of T cells restricted by major histocompatibility complex molecules, the rejection of organ transplants and the formation of T-cell-dependent antibodies. Dendritic cells are found in many non-lymphoid tissues, such as skin (Langerhans cells) and mucosa, and they migrate after antigen capture through the afferent lymph or the bloodstream to lymphoid organs, where they efficiently present antigen to T cells. Dendritic cells are difficult to isolate and, although they originate from bone marrow their site of maturation and the conditions that direct their growth and differentiation are still poorly characterized. Granulocyte macrophage-colony stimulating factor (GM-CSF) favours the outgrowth of dendritic cells from mouse peripheral blood. Here we extend this finding to man and demonstrate that cooperation between GM-CSF and tumour necrosis factor-alpha (TNF-alpha) is crucial for the generation of human dendritic/Langerhans cells from CD34+ haematopoietic progenitors. The availability of large numbers of these cells should now facilitate the understanding of their role in immunological regulation and disorder.

Antigens, CD↗

PubMed1992

Interferon-gamma enhances factor-dependent myeloid proliferation of human CD34+ hematopoietic progenitor cells.

Numerous studies have shown that interferon-gamma (IFN gamma) inhibits the proliferative effects of colony-stimulating factors (CSFs) on human bone marrow cells. In the present study we investigated the effects of IFN gamma and other described inhibitory factors on the proliferation of highly purified CD34+ human hematopoietic progenitor cells (HPC) in response to recombinant CSFs. While transforming growth factor-beta (TGF beta) and IFN alpha were highly inhibitory, IFN gamma strongly potentiated interleukin-3 (IL-3) and, to a lesser extent, granulocyte-macrophage-CSF (GM-CSF) induced growth of CD34+ HPC. IFN gamma had no significant proliferative effect per se, and did not affect granulocyte-CSF (G-CSF)-dependent cell proliferation. Within 10 days the number of viable cells generated in the presence of IL-3 + IFN gamma was two times higher than in the presence of IL-3 alone. Limiting dilution analysis showed that IFN gamma acts directly on its target cell to increase the frequency of IL-3-responding cells without affecting the average size of the IL-3-dependent clones. Enhanced frequency of IL-3- and GM-CSF-responding cells was also observed in colony assays where the addition of IFN gamma increased by twofold to threefold the number of granulocyte colony-forming units (CFU-G), macrophage CFUs (CFU-M), granulocyte-macrophage CFUs (CFU-GM), and mixed erythroid (E-MIX). In contrast, IFN gamma did not affect the generation of erythroid burst-forming units (BFU-e) in such cultures. In longer-term culture, the combination of IFN gamma and IL-3 did not alter the lineage distribution of the cells when compared with IL-3 alone. However, after 15 days, when mature cells were present in the cultures, IFN gamma displayed cell concentration-related growth-inhibitory effects. Thus, IFN gamma appears to stimulate the early stage of myelopoiesis by enhancing the frequency of growth factor-responding cells but, unlike tumor necrosis factor alpha (TNF alpha), does not alter cell differentiation.

Adult↗

PubMed1992

Modification of human long-term bone marrow cultures: establishment of a functional stromal microenvironment devoid of myeloid progenitors.

Differences in the plastic adhesive properties of bone marrow (BM) cells were used to initiate modified stromal layers (MSL) from long-term cultures by removing non-adherent cells shortly (4 to 18 hours) after initial seeding. Following this early modification, adherent cells generated a confluent layer after 21 days of culture. Cellular characteristics of volume and spontaneous fluorescence determined by flow cytometry showed that the MSL included 82% fibroblastic stromal cells, 8% macrophages and 10% myelomonocytic cells. Furthermore, clonogenic assays revealed that the MSL were devoid of hematopoietic progenitor cells. MSL were found to sustain long-term myelopoiesis for at least 7 weeks from exogenously added hematopoietic progenitors isolated from bone marrow (CD34+ cells), thereby demonstrating their functionality. The present experimental model appears of interest for the study of interactions between defined populations of hematopoietic cells and cells of the adherent layer. Of importance, our present modifications of human long-term bone marrow culture are technically simple and do not involve manipulation of the stromal cells.

Antigens, CD↗

PubMed1992

Canine systemic lupus erythematosus. I: A study of 75 cases.

We studied 75 cases of canine systemic lupus erythematosus (SLE) presenting with at least four criteria of the American Rheumatism Association (ARA), including antinuclear antibodies (ANAb). This disease mainly affects male German shepherds of an average age of 5 years. The most common clinical signs are polyarthritis (91% of cases), and renal (65%) and cutaneo-mucous disorders (60%). Hemolytic anemia is rare (13%). ANAb are present, often at high levels (> 256 up to 10(6) by indirect immunofluorescence on mouse blood smears). The titers are correlated with the severity and the stage of the disease. As double-stranded DNA Ab are rare and as antihistone Ab are frequent, the former could be replaced by the latter in the ARA criteria applied to the SLE dog. Another category of ANAb, named anti-type 1, also seems useful in diagnosing canine SLE. As for therapy, long-term remissions (up to 9 years without treatment) were obtained in 55.6% of 27 SLE dogs treated by levamisole. At first, levamisole was associated with induction corticotherapy, then administered alone and finally discontinued. Side effects were uncommon and transient.

Animals↗

PubMed1992

Canine systemic lupus erythematosus. II: Antinuclear antibodies.

The frequency and the specificities of antinuclear antibodies (ANAb) were studied in dogs with systemic lupus erythematosus (SLE) and compared to those found in normal dogs and in dogs with various infectious diseases. Whole ANAb were detected by immunofluorescence. Anti-double-stranded DNA Ab were found in only 2% of SLE dogs, whereas anti-single-stranded DNA Ab were present in 21.4% of SLE dogs and in 26.8% of dogs with infectious disease. Antihistone Ab were frequently observed in SLE dogs (71%) and are essentially directed against trypsin-resistant epitopes of H3, H4 and H2A. The Western blots of nuclear extracts of HeLa cells were recognized mainly by type 1 Ab (30%, reacting with bands of 43, 36, 35, 34, 30 and 27 kDa) and by anti-Sm Ab (12%) associated with anti-RNP Ab. Anti-SSA and anti-SSB Ab were rare.

Animals↗

PubMed1992

Distribution of surface-membrane molecules on bone marrow and cord blood CD34+ hematopoietic cells.

We have investigated the distribution of membrane molecules on CD34+ hematopoietic cells isolated from human bone marrow (BM) and cord blood (CB). A distinct CD10+ population was present in BM, but it was not detected in CB. Most CD34+ CD10+ cells in BM were B-cell precursors (BCP), because they expressed CD19. However, CD40 and CD37 were found on the majority of CD34+ cells from either BM or CB, demonstrating that these antigens are not restricted to B-lineage CD34+ cells. CD40 and CD37 were lost during culture of CD34+ cells in the presence of interleukin 3 (IL-3), indicating transient expression early in myeloid development. CD13 antigen was detected on virtually all CD34+ cells from BM and CB. Accordingly, CD13 was present on CD34+ CD10+ cells, demonstrating that this structure is not restricted to myeloid CD34+ cells. In contrast, myeloid CD33 antigen was not detected on CD34+ CD10+ cells. Expression levels of CD13 and of CD33 were heterogeneous in BM, reflecting diversity within the resident CD34+ population. CD25 and CD71 were found on a proportion of CD34+ cells from either BM or CB and maintained during culture in IL-3, consistent with a distribution on activated cells. Finally, a variety of adhesion receptors were present on CD34+ cells. These included the alpha 4 beta 1 (VLA-4), alpha 5 beta 1 (VLA-5), and alpha L beta 2 (LFA-1) integrins, as well as ICAM-1, LFA-3, H-CAM, and LAM-1. Expression of adhesion receptors was remarkably similar in BM and CB, and it followed an all-or-nothing pattern that failed to delineate CD34+ subsets. Taken together, our data show that although CD34+ cells from BM constitute a more heterogeneous population, resident and circulating CD34+ cells largely display the same cell-surface molecules.

Antigens, CD↗

PubMed1991

Interleukin-7 induces the proliferation of normal human B-cell precursors.

In the present study, we investigated the effects of human recombinant interleukin-7 (IL-7) on the proliferation of enriched hematopoietic cells isolated from human adult and fetal bone marrow (BM). In cultures of CD34+ cells, IL-7 was found to induce dose-dependent incorporation of 3H-thymidine (3H-TdR), but had no demonstrable effect on the development of myeloid colony-forming cells. Numbers of B-cell precursors (BCP), initially present within CD34+ populations and which included a CD34+CD20+ subset, were significantly increased when CD34+ BM cells were cultured in the presence of IL-7. This effect was most striking on CD20+ BCP, and resulted at least partly from higher numbers of cycling cells as indicated by Hoechst 33342 fluorescence (Calbiochem, Behring Diagnostics, La Jolla, CA). These results indicate that IL-7 promotes the growth of BCP within the CD34+ compartment. In line with the B-lineage affiliation of CD34+ target cells, committed BCP (CD10+ CD19+ surface IgM-) isolated from BM were also found to proliferate in response to IL-7. Interestingly, this effect of IL-7 was strongly potentiated by the addition of IL-3. Taken together, and in accordance with previous observations on murine cells, our data indicate that IL-7 acts as a growth factor during the ontogeny of human B lymphocytes.

Adult↗

PubMed1991

Potentiation of early hematopoiesis by tumor necrosis factor-alpha is followed by inhibition of granulopoietic differentiation and proliferation.

We have previously shown that tumor necrosis factor-alpha (TNF alpha) strongly potentiates interleukin-3 (IL-3)-induced short-term proliferation of human CD34+ hematopoietic progenitor cells (HPC). Using longer term cultures of CD34+ HPC, we demonstrate here that this initial potentiation ceases after 10 to 12 days; whereupon TNF alpha displays inhibitory effects. Thus, TNF alpha was found to inhibit cells of granulocytic affiliation while it potentiates the development of maturing cells of the monocytic lineage both in liquid and semi-solid (day 14 colony-forming unit) cultures. TNF alpha was demonstrated to reversibly block granulocytic differentiation at the level of uncommitted CD13-, CD15- blast cells that accumulate in IL-3 + TNF alpha cultures. Furthermore, growth of committed granulocytes (CD15+) from IL-3 cultures was also inhibited by TNF alpha through an arrest of cell cycle in G0/G1. Finally, the use of neutralizing anti-TNF alpha monoclonal antibody and limiting dilution studies indicate that the inhibitory effects of TNF alpha are direct. Taken together, our data demonstrate that, following a phase of potentiation of proliferation of early HPC, TNF alpha displays direct inhibitory effects due to negative interference with both granulocytic differentiation and proliferation of granulocytic cells.

Antibodies, Monoclonal↗

PubMed1990

Tumor necrosis factor-alpha strongly potentiates interleukin-3 and granulocyte-macrophage colony-stimulating factor-induced proliferation of human CD34+ hematopoietic progenitor cells.

Previous studies have shown that tumor necrosis factors (TNFs) inhibit the proliferative effects of crude or purified colony-stimulating factors (CSFs) on low density human bone marrow cell fractions. In the present study we investigated the effects of TNF alpha on the growth of highly purified CD34+ human hematopoietic progenitor cells (HPC) in response to recombinant CSFs. In short-term liquid cultures (5 to 8 days), TNF alpha strongly potentiates interleukin-3 (IL-3) and granulocyte-macrophage-CSF (GM-CSF)-induced growth of CD34+ HPC, while it has no proliferative effect per se. Within 8 days, the number of viable cells obtained in TNF alpha-supplemented cultures is threefold higher than in cultures carried out with IL-3 or GM-CSF alone. Secondary liquid cultures showed that the potentiating effect of TNF alpha on IL-3-induced proliferation of CD34+ HPC does not result from an IL-3-dependent generation of TNF alpha responsive cells. Limiting dilution analysis indicates that TNF alpha increases both the frequency of IL-3 responding cells and the average size of the IL-3-dependent clones. The potentiating effect of TNF alpha on IL-3- and GM-CSF-dependent growth of CD34+ HPC is also observed in day 7 colony assays. Under these short-term culture conditions, TNF alpha does not appear to accelerate cell maturation as a precursor morphology is retained. Finally, TNF alpha inhibits the relatively weak growth-promoting effect of granulocyte-CSF (G-CSF), which acts on a more committed subpopulation of CD34+ HPC different from that recruited by IL-3 and GM-CSF. TNF beta displays the same modulatory effects as TNF alpha. Thus, TNFs appear to enhance the early stages of myelopoiesis.

Antigens, CD↗

PubMed1990

Interleukin-4 has basophilic and eosinophilic cell growth-promoting activity on cord blood cells.

Effects of human recombinant interleukin-4 (IL-4) on cord blood cells depleted of T cells and monocytes were tested in colony assays and liquid cultures. IL-4 did not induce colony formation in semisolid medium, but enhanced generation of basophil colonies induced by conditioned medium (CM) of the bladder carcinoma cell line 5637. In liquid cultures, variable degrees of basophil growth were observed in the presence of IL-3, granulocyte-macrophage colony-stimulating factor (GM-CSF), G-CSF, and 5637 CM, or even with IL-4 alone, but the highest number of basophils were obtained when IL-4 was used in combination with IL-3 or 5637 CM. Progressive basophil growth was observed during 3 to 4 weeks of culturing, whereafter the numbers of basophils remained stationary for another 3 weeks. Interestingly, cord blood cell cultures performed with IL-3 contained variable percentages of eosinophils that were further enhanced in the presence of combinations of IL-3 and IL-4. These latter cultures contained approximately 50% eosinophils and 50% basophils. Kinetic studies indicated that basophils were present 7 days after onset of the cultures, whereas eosinophils did not appear before day 13. In contrast to the pronounced effects of IL-4 and 5637 CM on basophil development, relatively low numbers of eosinophils were observed under these culture conditions. Our results indicate that eosinophil and basophil development are regulated by different sets of factors, and that IL-4 has an enhancing effect of both cell lineages in association with the appropriate factors.

Basophils↗

PubMed1989

Recombinant human IL-3 and G-CSF act synergistically in stimulating the growth of acute myeloid leukemia cells.

The effects of combinations of recombinant human growth factors (colony-stimulating factor (CSF], interleukin 3 (IL-3), granulocyte-macrophage colony-stimulating factor (GM-CSF), and granulocyte colony stimulating factor (G-CSF) for inducing proliferation of leukemic cells were compared in 27 acute myeloid leukemias (AMLs). While functional heterogeneity of AML was clearly shown, we further demonstrated that optimal growth may be obtained with combinations of CSF. The most striking feature was that, in both suspension and semisolid cultures, IL-3 and G-CSF acted synergistically in supporting AML cell proliferation except in cases for which G-CSF was found to be an inhibitory factor. In the majority of cases, the proliferative effects of the IL-3 and GM-CSF combination were significantly higher than the most potent of either factor present alone in the cultures. Finally, preincubation with IL-3 greatly potentiated the responsiveness of AML cells to subsequent addition of either GM-CSF or G-CSF. These results indicate that AML cells respond to growth factor in the same way as normal hemopoietic cells and that stimulation by a second late-acting growth factor such as G-CSF is also required to yield optimal growth.

Cell Division↗

PubMed1989

Combined and sequential effects of human IL-3 and GM-CSF on the proliferation of CD34+ hematopoietic cells from cord blood.

The proliferative effects of recombinant human interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) were investigated in semi-solid and liquid cultures of purified CD34+ hematopoietic cells obtained from umbilical cord blood. No important differences in overall cloning efficiencies in response to IL-3 or GM-CSF were observed in semi-solid medium in the presence of erythropoietin (Ep). However, GM-CSF was less effective for the development of erythroid bursts (BFU-E), and only IL-3 was observed to induce significant numbers of mixed-erythroid colonies (E-MIX). Both IL-3 and GM-CSF also induced proliferation of CD34+ in liquid cultures. Proliferative responses to IL-3 were found to be more rapid and stronger than to GM-CSF, although the number of initial responsive cells as judged by autoradiography were comparable. Enhanced proliferation of CD34+ cells both in semi-solid and liquid cultures was obtained in the presence of combinations of IL-3 and GM-CSF. The responses observed were less than additive, with the exception of the development of eosinophil colonies and clusters, where IL-3 and GM-CSF were found to act synergistically. In secondary cultures, proliferative responses to GM-CSF were strongly enhanced by preculture of CD34+ cells in IL-3 for four to 11 days, and to a lesser extent by preculture in GM-CSF. Finally, responses to IL-3 were not affected by preculture of CD34+ cells in the presence of GM-CSF. Our results indicate that there is a wide overlap of cells capable of proliferating either in response to IL-3 or to GM-CSF within the cord blood CD34+ compartment. However, differences in primary proliferation kinetics and increased responsiveness to GM-CSF following preculture suggest the importance of a sequential action of IL-3 and GM-CSF in the expansion of CD34+ cells.

Antigens, CD34↗

PubMed1989

Sequential loss of CD34 and class II MHC antigens on purified cord blood hematopoietic progenitors cultured with IL-3: characterization of CD34-, HLA-DR+ cells.

The expression of class II MHC and CD34 antigens on human cord blood hematopoietic progenitor cells (HPC) was investigated upon culturing in the presence of interleukin-3 (IL-3). HPC isolated by "panning" according to their expression of CD34 coexpressed HLA-DR and HLA-DP, and the majority of the CD34+ HPC also expressed HLA-DQ. In the presence of IL-3, the expression of CD34 and class II MHC antigens was found to be gradually lost in culture. Loss of CD34 expression preceded loss of HLA-DR expression. After eight days of culture, CD34-, HLA-DR+ blast cells were obtained that strongly proliferated in response to IL-3, GM-CSF, G-CSF, and M-CSF, and that had the capacity to generate macrophage and granulocyte colonies. After ten days of culture in IL-3, a population of CD34- cells that expressed low levels of HLA-DR (HLA-DRlo) was obtained by FACS-sorting. These CD34-, HLA-DRlo cells lacked colony-forming activity while the population expressing high levels of HLA-DR (HLA-DRhi) contained great numbers of colony-forming cells, and proliferated stronger in response to CSFs than the HLA-DRlo fraction. Finally CD34-, HLA-DR- cells that appeared later in the cultures (14 to 16 days) represented more differentiated cells with only marginal proliferative and no clonogenic capacity. These data indicate that whereas CD34 expression is associated with the multilineage potential of the HPC, HLA-DR expression correlates with overall proliferative capacity of hematopoietic cells during culture in IL-3.

Antigens, CD34↗