Normal Human Cord Blood B Cells can Produce High Affinity IgG Antibodies to dsDNA that are Recognized by Cord Blood-Derived Anti-Idiotypic Antibodies

Abstract Previously, we demonstrated that BMI1 acts as a stem cell maintenance factor for human stem/progenitor cells. Here, we report that BMI1 collaborates with BCR-ABL in inducing leukemogenic transformation of human cord blood (CB) CD34+ cells. BMI1 and BCR-ABL were co-expressed into CB CD34+ cells (further referred as B/B cells) using a retroviral approach and cells were transplanted into NOD-SCID mice. In two out of five mice we observed leukemia within 4 months after transplantation. Chimerism levels reached 80–90% in the bone marrow and peripheral blood and morphological analysis revealed the appearance of primitive blast-like human hematopoietic cells with features that recapitulate human lymphoid leukemia. The mice were lethargic, with splenomegaly and infiltration of leukemic cells in the spleen, liver and the bone marrow and immunophenotypical analyses revealed that the cells expressed CD34 and CD19. To further understand the mechanisms underlying the leukemic transformation we performed ex-vivo long-term cultures on bone marrow stroma. We observed that the double transduced B/B cells had a strong proliferative advantage and elevated self-renewal potential as compared to controls. Expanding cultures could be maintained for over 20 weeks and Cobblestone Area Forming Cells (CAFCs) could be harvested and replated to initiate new expanding cocultures. Stem cell frequencies were determined in Long-Term Culture-Initiating Cell (LTC-IC) assays and frequencies were enhanced over 100-fold as compared to controls. Depending on the MS5 co-culture conditions, both myeloid as well as lymphoid long-term cultures could be established, indicating that extrinsic factors might dictate the lineage fate of transformed cells. To determine the necessity of a bone marrow microenvironment, we performed stroma-free liquid cultures and observed that the B/B cells were capable of expanding over 23 weeks, BMI1 cells were able to grow for 16 weeks and, importantly, BCR-ABL cells were not able to propagate long-term in stromain-dependent cultures. Thus, these data suggest that BCR-ABL cells are still dependent on cues from the bone marrow microenvironment for long-term self-renewal, and that co-expression of the intrinsic stem cell regulator BMI1 might alleviate this necessity of BCR-ABL+ cells for a microenvironment. Experiments in which B/B-transduced cells were sorted into HSC, CMP, GMP and MEP populations indicated that long-term self-renewal and expansion could particularly be imposed on the HSC population, and much less efficiently on progenitor subpopulations. In order to study whether the B/B-leukemic stem cells could be targeted by Imatinib, we applied a short pulse of Imatinib to expanding MS5 cocultures for 7 days. While the vast majority of cells in all cultures did not survive, in the B/B-transduced group a population of immature cells remained that was capable of re-initiating proliferative cultures of self-renewing CAFCs with very high frequencies (1/96 as determined by LTC-IC assays). Finally, we asked whether retroviral introduction of BMI1 in BCR-ABL+ CD34+ cells isolated from CML patients in chronic phase that expressed low endogenous BMI1 levels would affect long-term growth and self-renewal. Upon overexpression of BMI1 we observed increased proliferation capacity of the BMI1 transduced CML cells, and cultures could be maintained for much longer periods than control-transduced cultures. In conclusion, our data indicate that BMI1 collaborates with BCR-ABL in leukemic transformation, and our human-based system should provide a useful model to study the pathology of leukemias and test new drug entities.

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Selective Clearance of Chronic Lymphocytic Leukemia Cells in Vivo Following Treatment with UC99961, an Anti-ROR1 Monoclonal Antibody

Blood ◽

10.1182/blood.v120.21.3886.3886 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3886-3886

Author(s):

Eva Hellqvist ◽

Christina C.N. Wu ◽

George F. Widhopf ◽

Alice Shih ◽

Rommel Tawatao ◽

...

Keyword(s):

Monoclonal Antibody ◽

T Cells ◽

B Cells ◽

Chronic Lymphocytic Leukemia ◽

Cord Blood ◽

Peritoneal Lavage ◽

Lymphocytic Leukemia ◽

Leukemia Cells ◽

Human Cord Blood

Abstract Abstract 3886 ROR1 is a receptor-tyrosine kinase like protein expressed on the surface of chronic lymphocytic leukemia (CLL) B cells, but not on normal mature B cells, suggesting that it may be a promising therapeutic target. We have generated a chimeric monoclonal antibody (mAb), UC99961, which binds to an intradomain epitope of human ROR1 (hROR1). UC99961 binds the same epitope as the murine anti-hROR1 mAb, UC D10–001, which has direct cytotoxic effects on hROR1 positive CLL cells. In this study we investigated the in-vivo anti-leukemic activity and tolerability of UC99961 on ROR1+ primary patient CLL cells and human cord-blood-derived B cells and T cells, respectively. For these studies, immunodeficient RAG2−/−γc−/− neonatal mice were reconstituted with a human immune system by intrahepatic xenotransplantation of 1×105 CD34+ human cord blood progenitor cells. Eight to ten weeks post transplantation, cord blood engraftment was verified by peripheral blood screening, at which point the mice received an intraperitoneal transplantation of 2×107 primary patient ROR1+ CLL cells. Twenty-four hours after CLL transplantation, five animals per group were each treated with a single intraperitoneal injection (10mg/kg) of UC99961, UC D10–001, or control IgG. Seven days following mAb treatment, the animals were sacrificed and marrow, spleen, thymus, and peritoneal lavage samples were collected and analyzed by flow cytometry for CLL cells, as well as normal cord-blood-derived B cells and T cells. To confirm mAb administration according to the study design, serial residual ROR1 plasma antibody levels were determined by ELISA. Results from three consecutive experiments using leukemia cells from two different patients showed that the vast majority of CLL B cells remained in the peritoneal cavity of the animals and did not migrate to other hematopoietic organs. Both anti-hROR1 mAbs UC99961 and UC D10–001 significantly reduced the average number of harvested CLL cells in the peritoneal lavage compared to control IgG (99% and 71% reduction respectively), while cord-blood-derived T cells (CD45+3+) in thymus remained unaffected by the mAb treatment. For the majority of cord-blood-derived B cells in marrow and spleen, no significant reduction could be observed after UC99961 or UC D10–001 mAb treatment. A small CD19+ROR1+CD34− cord-blood-derived B cell population was identified in marrow and spleen that was reduced after UC99961 and UC D10–001 mAb treatment. This study demonstrates that the anti-human ROR1 specific mAbs have in vivo anti-leukemic activity with minimal impact on human cord-blood-derived B cells and T cells. From these results, UC99961 appears to be an excellent candidate antibody for future clinical studies for patients with CLL. Disclosures: No relevant conflicts of interest to declare.

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Expression of CD10 and CD7 Defines Distinct In Vivo Lymphoid Reconstituting Capacity within Human Cord Blood CD34+CD38-Cells.

Blood ◽

10.1182/blood.v108.11.3184.3184 ◽

2006 ◽

Vol 108 (11) ◽

pp. 3184-3184

Author(s):

Shuro Yoshida ◽

Fumihiko Ishikawa ◽

Leonard D. Shultz ◽

Noriyuki Saito ◽

Mitsuhiro Fukata ◽

...

Keyword(s):

Bone Marrow ◽

T Cells ◽

B Cells ◽

Cord Blood ◽

Nk Cells ◽

Progenitor Cells ◽

Human Cord Blood ◽

Cd34 Cells

Abstract Human cord blood (CB) CD34+ cells are known to contain both long-term hematopoietic stem cells (LT-HSCs) and lineage-restricted progenitor cells. In the past, in vitro studies suggested that CD10, CD7 or CD127 (IL7Ra) could be candidate surface markers that could enrich lymphoid-restricted progenitor cells in human CB CD34+ cells (Galy A, 1995, Immunity; Hao QL, 2001, Blood; Haddad R, 2004, Blood). However, in vivo repopulating capacity of these lymphoid progenitors has not been identified due to the lack of optimal xenogeneic transplantation system supporting development of human T cells in mice. We aim to identify progenitor activity of human CB CD34+ cells expressing CD10/CD7 by using newborn NOD-scid/IL2rgKO transplant assay that can fully support the development of human B, T, and NK cells in vivo (Ishikawa F, 2005, Blood). Although LT-HSCs exist exclusively in Lin-CD34+CD38- cells, not in Lin-CD34+CD38+ cells, CD10 and CD7 expressing cells are present in Lin-CD34+CD38- cells as well as in Lin-CD34+CD38+ cells (CD10+CD7+ cells, CD10+CD7- cells, CD10-CD7+ cells, CD10-CD7- cells accounted for 4.7+/−2.7%, 10.5+/−1.9%, 7.6+/−4.4%, and 77.1+/−5.2% in Lin-CD34+CD38- CB cells, respectively). We transplanted 500–6000 purified cells from each fraction into newborn NOD-scid/IL2rgKO mice, and analyzed the differentiative capacity. CD34+CD38-CD10-CD7- cells engrafted long-term (4–6 months) in recipient mice efficiently (%hCD45+ cells in PB: 30–70%, n=5), and gave rise to all types of human lymphoid and myeloid progeny that included granulocytes, platelets, erythroid cells, B cells, T cells, and NK cells. Successful secondary reconstitution by human CD34+ cells recovered from primary recipient bone marrow suggested that self-renewing HSCs are highly enriched in CD34+CD38–CD10–CD7- cells. CD10–CD7+ cells were present more frequently in CD34+CD38+ cells rather than in CD34+CD38- cells. Transplantation of more than 5000 CD34+CD38+CD10–CD7+ cells, however, resulted in less than 0.5% human cell engraftment in the recipients. Within CD34+CD38–CD10+ cells, the expression of CD7 clearly distinguished the distinct progenitor capacity. At 8 weeks post-transplantation, more than 70% of total human CD45+ cells were T cells in the CD10+CD7+ recipients, whereas less than 30% of engrafted human CD45+ cells were T cells in the CD10+CD7– recipients. In the CD10+CD7- recipients, instead, more CD19+ B cells and HLA–DR+CD33+ cells were present in the peripheral blood, the bone marrow and the spleen. Both CD34+CD38–CD10+CD7+ and CD34+CD38–CD10+CD7- cells highly repopulate recipient thymus, suggesting that these progenitors are possible thymic immigrants. Taken together, human stem and progenitor activity can be distinguished by the expressions of CD7 and CD10 within Lin-CD34+CD38- human CB cells. Xenotransplant model using NOD-scid/IL2rgKO newborns enable us to clarify the heterogeneity of Lin-CD34+CD38- cells in CB by analyzing the in vivo lymphoid reconstitution capacity.

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Human Cord Blood B Cells Differ from the Adult Counterpart by Conserved Ig Repertoires and Accelerated Response Dynamics

The Journal of Immunology ◽

10.4049/jimmunol.2100113 ◽

2021 ◽

pp. ji2100113

Author(s):

Bettina Budeus ◽

Artur Kibler ◽

Martina Brauser ◽

Ekaterina Homp ◽

Kevin Bronischewski ◽

...

Keyword(s):

B Cells ◽

Cord Blood ◽

Response Dynamics ◽

Human Cord Blood

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Pre-B Cells and B Lymphocytes in Human Cord Blood and Adult Peripheral Blood

Pediatrics International ◽

10.1111/j.1442-200x.1987.tb00032.x ◽

1987 ◽

Vol 29 (2) ◽

pp. 195-201 ◽

Cited By ~ 3

Author(s):

Fumiko Okino

Keyword(s):

B Cells ◽

Cord Blood ◽

B Lymphocytes ◽

Peripheral Blood ◽

Human Cord Blood ◽

Adult Peripheral Blood

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Plaque-Forming Cells in Human Cord Blood: A Soluble Factor Suppressing Differentiation but Not Proliferation of B Cells

International Archives of Allergy and Immunology ◽

10.1159/000233160 ◽

1982 ◽

Vol 69 (2) ◽

pp. 132-136 ◽

Cited By ~ 2

Author(s):

Rafi Ahmad ◽

Christoph C. Zielinski ◽

Josef W. Mannhalter ◽

Gerhard Zlabinger ◽

Alfred Rockenschaub ◽

...

Keyword(s):

B Cells ◽

Cord Blood ◽

Soluble Factor ◽

Human Cord Blood

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Phenotype and Function of CD25-Expressing B Lymphocytes Isolated from Human Umbilical Cord Blood

Clinical and Developmental Immunology ◽

10.1155/2011/481948 ◽

2011 ◽

Vol 2011 ◽

pp. 1-9 ◽

Cited By ~ 5

Author(s):

Sylvie Amu ◽

Mikael Brisslert

Keyword(s):

B Cells ◽

Cord Blood ◽

B Cell ◽

Cell Subset ◽

Cell Populations ◽

Human Umbilical Cord Blood ◽

Human Umbilical Cord ◽

Common Denominator ◽

Human Cord Blood ◽

And Function

Background. We have shown that approximately 30% of human peripheral blood B-cells express CD25. B cells expressing CD25 display a mature phenotype belonging to the memory B-cell population and have a better proliferative and antigen-presenting capacity. The aim of the present study was to characterize the CD25-expressing subset of B cells in human cord blood.Material and Methods. Mononuclear cell fraction from human cord blood (n=34) and peripheral adult blood (n=22) was sorted into CD20+CD25+and CD20+CD25-B-cell populations. Phenotype and function of these B-cell populations were compared using flow cytometry, proliferation, cytokine production, and immunoglobulin secretion.Results. CD25-expressing B cells are a limited population of cord blood mononuclear cells representing 5% of the CD20+B cells. They are characterised by high expression of CD5 in cord blood and CD27 in adult blood. CD25-expressing B cells express a functional IL-2 receptor and high levels of CC-chemokine receptors and spontaneously produce antibodies of IgG and IgM subclass.Conclusions. CD25 expression is a common denominator of a specific immunomodulatory B-cell subset ready to proliferate upon IL-2 stimulation, possibly ready to migrate and home into the peripheral tissue for further differentiation/action.

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Demonstration of a natural antigalactosyl IgG antibody on thalassemic red blood cells

Blood ◽

10.1182/blood.v61.6.1258.bloodjournal6161258 ◽

1983 ◽

Vol 61 (6) ◽

pp. 1258-1264 ◽

Cited By ~ 1

Author(s):

U Galili ◽

A Korkesh ◽

I Kahane ◽

EA Rachmilewitz

Keyword(s):

Sialic Acid ◽

Myeloid Cell ◽

Reticuloendothelial System ◽

Igg Antibodies ◽

Igg Antibody ◽

High Affinity ◽

Rbc Membrane ◽

Antiglobulin Test ◽

Normal Human ◽

Galactosyl Residues

A modified antiglobulin test, based on the high affinity between the Fc portion of the red blood cell (RBC) bound IgG and the Fc receptor on the myeloid cell K-562, was utilized for demonstration of immunoglobulins (Ig) on thalassemic RBC. Ig was found on the RBC of 73 out of 80 patients with thalassemia. The immunoglobulins on the thalassemic RBC belonged to the IgG subclass and were autoreactive. Elution studies utilizing various carbohydrates, or by thermal stripping, indicated that at least part of the IgG molecules found on the thalassemic RBC were specifically reactive with terminal galactosyl residues on the RBC membrane. IgG antibodies with similar reactivity were also demonstrated in normal human serum. These natural antigalactosyl IgG antibodies from normal sera could bind to IgG- depleted thalassemic RBC. Thalassemic RBC and normal senescent RBC were previously found to contain reduced amounts of membrane sialic acid (SA). It is suggested that the antigalactosyl IgG antibodies interact with newly exposed galactosyl residues underlying the sialic acid units. Such interaction may lead to the shortened lifespan of thalassemic RBC and may result in sequestration of senescent normal RBC by the reticuloendothelial system.

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Suppression of B-Cell Activation by Human Cord Blood-Derived Stem Cells (CB-SC) through the Galectin-9-Dependent Cell Contact Mechanism

10.1101/2021.10.07.463564 ◽

2021 ◽

Author(s):

Wei Hu ◽

Xiang Song ◽

Haibo Yu ◽

Sophia Fan ◽

Andrew Shi ◽

...

Keyword(s):

Stem Cells ◽

Flow Cytometry ◽

Stem Cell ◽

B Cells ◽

Cord Blood ◽

Molecular Mechanisms ◽

Cell Contact ◽

Human Cord Blood ◽

Contact Mechanism ◽

Activated B Cells

Background: We developed the Stem Cell Educator therapy among multiple clinical trials based on the immune modulations of multipotent cord blood-derived stem cells (CB-SC) on different compartments of immune cells such as T cells and monocytes/macrophages in diabetes and other autoimmune diseases. However, the effects of CB-SC on the B cells remained unclear. To better understand the molecular mechanisms underlying the immune education of CB-SC, we explored the modulations of CB-SC on human B cells. Methods: CB-SC were isolated from human cord blood units and confirmed by flow cytometry with different markers for their purity. B cells were purified by using anti-CD19 immunomagnetic beads from human peripheral blood mononuclear cells (PBMC). Next, the activated B cells were treated in the presence or absence of coculture with CB-SC for 7 days before undergoing flow cytometry analysis of phenotypic change with different markers. RT-PCR was utilized to evaluate the levels of galectin expressions with or without treatment of activated B cells in order to find the key galectin contributing to the B-cell modulation. Results: Flow cytometry demonstrated that the proliferation of activated B cells was markedly suppressed in the presence of CB-SC, leading to the down-regulation of immunoglobulin productions from the activated B cells. Phenotypic analysis revealed that treatment with CB-SC increased the percentage of IgD+CD27- naive B cells, but decreased the percentage of IgD-CD27+ switched B cells. Transwell assay showed that the immune suppression of CB-SC on B cells was dependent on the manner of cell-cell contact via Gal-9 molecule, as confirmed by the blocking experiment with the anti-Gal-9 monoclonal antibody. Mechanistic studies demonstrated that both calcium levels of cytoplasm and mitochondria were down-regulated after the treatment with CB-SC, causing the decline of mitochondrial membrane potential in the activated B cells. Western blot exhibited that the levels of phosphorylated Akt and Erk1/2 signaling proteins in the activated B cells were also markedly reduced in the presence of CB-SC. Conclusions: CB-SC displayed multiple immune modulations on B cells through the Gal-9-mediated cell-cell contact mechanism and calcium flux/Akt/Erk1/2 signaling pathways. The data advances current understanding about the molecular mechanisms underlying the Stem Cell Educator therapy to treat autoimmune diseases in clinics.

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