scholarly journals Normal Plasma Cell Biology: Natural Achilles Heels as Targets in Myeloma

Blood ◽  
2017 ◽  
Vol 130 (Suppl_1) ◽  
pp. SCI-7-SCI-7
Author(s):  
Katia Georgopoulos
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Gene Family ◽  
B Cell ◽  
Plasma Cell ◽  
Cell Biology ◽  
Plasma Cells ◽  
B Cell Differentiation ◽  
High Affinity ◽  
Bone Marrow Plasma

Abstract Normal Plasma Cell Biology: Natural Achilles Heels as Targets in MyelomaÊ Primary exposure to antigen leads to affinity maturation, selection and terminal differentiation of mature B cells to antibody-secreting plasma cells. Long-lived high-affinity plasma cells and their immediate precursors reside in the bone marrow and are responsible for rapid recall reactions and a life-time production of high affinity antibodies. Members of the IKAROS gene family have been specifically implicated in the generation of long-lived plasma cells. Mice deficient for Aiolos, the B cell specific member of the IKAROS gene family fail to produce high affinity plasma cells in the bone marrow and to sustain serum antibody titers after both primary or secondary immunization with a range of hapten concentrations. Chimera reconstitutions have demonstrated that the bone marrow plasma cell defect is B cell intrinsic. However, lack of AIOLOS does not alter expression of any of the previously described factors required for B cell differentiation into the plasma cell stage. No defect in somatic hyper-mutation, the generation of memory B cells, or short-lived high affinity plasma cells in the spleen is observed upon challenge or re-challenge. Thus this IKAROS family member is critically required for high-affinity bone plasma cells possibly by regulating their interaction with the bone marrow microenvironment, a process that is likely critical for long-term survival. High-affinity bone marrow plasma cells are the normal counterpart of the devastating B cell malignancy multiple myeloma. Multiple myeloma is treatable with immune modulatory drugs (IMiD) such as lenalidomide. Recent studies have shown that IMiD alter the specificity of the CRL4-CEREBLON (CRL4CRBN) E3 ubiquitin ligase complex. Among the new targets for the CRL4CRBN complex are two of the IKAROS family members, AIOLOS and IKAROS, whose degradation adversely affects the cellular fitness of multiple myeloma cells. Recent studies in B cell precursors have implicated the IKAROS gene family in the regulation of bone marrow stromal interactions. IKAROS and AIOLOS activities balance self-renewal, survival, and pre-B cell differentiation by engaging epigenetic and transcriptional machineries through discrete lineage-specific superenhancers. Such AIOLOS and IKAROS-dependent regulatory pathways engaged in early B cell precursors may also be involved in controlling bone marrow stromal interactions with high affinity plasma cells and their malignant counterparts thereby contributing to long-term growth and survival. Further exploitation of IKAROS family-targeted pathways in bone marrow plasma cells and multiple myeloma is warranted. Disclosures No relevant conflicts of interest to declare.

scholarly journals Multiple myeloma: circulating lymphocytes that express plasma cell antigens

Blood ◽  
1984 ◽  
Vol 64 (2) ◽  
pp. 352-356
Author(s):  
GJ Ruiz-Arguelles ◽  
JA Katzmann ◽  
PR Greipp ◽  
NJ Gonchoroff ◽  
JP Garton ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Plasma Cell ◽  
Peripheral Blood ◽  
Plasma Cells ◽  
Peripheral Blood Lymphocytes ◽  
Tumor Burden ◽  
B Cell Differentiation ◽  
Blood Lymphocytes ◽  
Bone Marrow Plasma

The bone marrow and peripheral blood of 14 patients with multiple myeloma were studied with murine monoclonal antibodies that identify antigens on plasma cells (R1–3 and OKT10). Peripheral blood lymphocytes expressing plasma cell antigens were found in six cases. Five of these cases expressed the same antigens that were present on the plasma cells in the bone marrow. Patients that showed such peripheral blood involvement were found to have a larger tumor burden and higher bone marrow plasma cell proliferative activity. In some patients, antigens normally found at earlier stages of B cell differentiation (B1, B2, and J5) were expressed by peripheral blood lymphocytes and/or bone marrow plasma cells.

scholarly journals Multiple myeloma: circulating lymphocytes that express plasma cell antigens

Blood ◽  
1984 ◽  
Vol 64 (2) ◽  
pp. 352-356 ◽  
Author(s):  
GJ Ruiz-Arguelles ◽  
JA Katzmann ◽  
PR Greipp ◽  
NJ Gonchoroff ◽  
JP Garton ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Plasma Cell ◽  
Peripheral Blood ◽  
Plasma Cells ◽  
Peripheral Blood Lymphocytes ◽  
Tumor Burden ◽  
B Cell Differentiation ◽  
Blood Lymphocytes ◽  
Bone Marrow Plasma

Abstract The bone marrow and peripheral blood of 14 patients with multiple myeloma were studied with murine monoclonal antibodies that identify antigens on plasma cells (R1–3 and OKT10). Peripheral blood lymphocytes expressing plasma cell antigens were found in six cases. Five of these cases expressed the same antigens that were present on the plasma cells in the bone marrow. Patients that showed such peripheral blood involvement were found to have a larger tumor burden and higher bone marrow plasma cell proliferative activity. In some patients, antigens normally found at earlier stages of B cell differentiation (B1, B2, and J5) were expressed by peripheral blood lymphocytes and/or bone marrow plasma cells.

scholarly journals Myeloma Cell Associated Therapeutic Protein Discovery Using Single Cell RNA-Seq Data

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 4-5
Author(s):  
Lijun Yao ◽  
Reyka G Jayasinghe ◽  
Tianjiao Wang ◽  
Julie O'Neal ◽  
Ruiyang Liu ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Cell Surface ◽  
B Cell ◽  
Tumor Cells ◽  
Plasma Cell ◽  
Tissue Specificity ◽  
Plasma Cells ◽  
Expression Data ◽  
Intracellular Proteins

Multiple myeloma (MM) is a hematological cancer of the antibody-secreting plasma cells. Despite therapeutic advancements, MM remains incurable due to high incidence of drug-resistant relapse. In recent years, targeted immunotherapies, which take advantage of the immune system's cytotoxic defenses to specifically eliminate tumor cells expressing certain cell surface and intracellular proteins have shown promise in combating this and other B cell hematologic malignancies. A major limitation in the development of these therapies lies in the discovery of optimal candidate targets, which require both high expression in tumor cells as well as stringent tissue specificity. In an effort to identify potential myeloma-specific target antigens, we performed an unbiased search for genes with specific expression in plasma and/or B cells using single-cell RNA-sequencing (scRNAseq) of 53 bone marrow samples taken from 42 patients. By comparing >40K plasma cells to >97K immune cells across our cohort, we were able to identify a total of 181 plasma cell-associated genes, including 65 that encode cell-surface proteins and 116 encoding intracellular proteins. Of particular interest is that the plasma cells from each patient were shown to be transcriptionally distinct with unique sets of genes expressed defining each patient's malignant plasma cells. Using pathway enrichment analysis, we found significant overrepresentation of cellular processes related to B-Cell receptor (BCR) signaling, protein transport, and endoplasmic reticulum (ER) stress, involving genes such as DERL3, HERPUD1, PDIA4, PDIA6, RRBP1, SSR3, SSR4, TXNDC5, and UBE2J1. To note, our strategy successfully captured several of the most promising MM therapeutic targets currently under pre-clinical and clinical trials, including TNFRSF17(BCMA), SLAMF7, and SDC1 (CD138). Among these, TNFRSF17 showed very high plasma cell expression, with concomitant sharp exclusion of other immune cell types. To ascertain tissue specificity of candidate genes outside of the bone marrow, we analyzed gene and protein expression data from the Genotype-Tissue Expression (GTEx) portal and Human Protein Atlas (HPA). We found further support for several candidates (incl. TNFRSF17,SLAMF7, TNFRSF13B (TACI), and TNFRSF13C) as being both exclusively and highly expressed in lymphoid tissues. While several surface candidates were not found to be lymphocyte-restricted at the protein level, they remain relevant considerations as secondary targets for bi-specific immunotherapy approaches currently under development. To further investigate potential combinatorial targeting, we examine sample-level patterns of candidate co-expression and mutually-exclusive expression using correlation analysis. As the majority of our detected plasma cell-specific genes encode intracellular proteins, we investigated the potential utility of these epitopes as therapeutic targets via MHC presentation. Highly expressed candidates include MZB1, SEC11C, HLA-DOB, POU2AF1, and EAF2. We analyzed protein sequences using NetMHC and NETMHCII to predict high-affinity peptides for common class-I and class-II HLA alleles. To correlate MHC allelic preference with candidate expression in our cohort, we performed HLA-typing for 29 samples using Optitype. To support our scRNAseq-driven findings, we cross-referenced gene expression data with 907 bulk RNA-sequencing samples, including 15 from internal studies and 892 from the Multiple Myeloma Research Foundation (MMRF), as well as bulk global proteomics data from 4 MM cell lines (TIB.U266, RPMI8226, OPM2, MM1ST) and 4 patients. We see consistent trends across both cohorts, with high positive correlation (Pearson R ranging between 0.60 and 0.99) for a majority of genes when comparing scRNA and bulk RNA expression in the same samples. Our experimental design and analysis strategies enabled the efficient discovery of myeloma-associated therapeutic target candidates. In conclusion, this study identified a set of promising myeloma CAR-T targets, providing novel treatment options for myeloma patients. Disclosures Goldsmith: Wugen Inc.: Consultancy. DiPersio:Magenta Therapeutics: Membership on an entity's Board of Directors or advisory committees.

scholarly journals Complement receptors regulate differentiation of bone marrow plasma cell precursors expressing transcription factors Blimp-1 and XBP-1

2005 ◽  
Vol 201 (6) ◽  
pp. 993-1005 ◽  
Author(s):  
Dominique Gatto ◽  
Thomas Pfister ◽  
Andrea Jegerlehner ◽  
Stephen W. Martin ◽  
Manfred Kopf ◽  
...  
Keyword(s):  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Plasma Cell ◽  
Cell Activation ◽  
Plasma Cells ◽  
Antibody Responses ◽  
Complement Receptors ◽  
Essentially Normal ◽  
Bone Marrow Plasma

Humoral immune responses are thought to be enhanced by complement-mediated recruitment of the CD21–CD19–CD81 coreceptor complex into the B cell antigen receptor (BCR) complex, which lowers the threshold of B cell activation and increases the survival and proliferative capacity of responding B cells. To investigate the role of the CD21–CD35 complement receptors in the generation of B cell memory, we analyzed the response against viral particles derived from the bacteriophage Qβ in mice deficient in CD21–CD35 (Cr2−/−). Despite highly efficient induction of early antibody responses and germinal center (GC) reactions to immunization with Qβ, Cr2−/− mice exhibited impaired antibody persistence paralleled by a strongly reduced development of bone marrow plasma cells. Surprisingly, antigen-specific memory B cells were essentially normal in these mice. In the absence of CD21-mediated costimulation, Qβ-specific post-GC B cells failed to induce the transcriptional regulators Blimp-1 and XBP-1 driving plasma cell differentiation, and the antiapoptotic protein Bcl-2, which resulted in failure to generate the precursor population of long-lived plasma cells residing in the bone marrow. These results suggest that complement receptors maintain antibody responses by delivery of differentiation and survival signals to precursors of bone marrow plasma cells.

The Natural History of Smoldering (Asymptomatic) Multiple Myeloma.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 3396-3396 ◽  
Author(s):  
Robert Kyle ◽  
Ellen Remstein ◽  
Terry Therneau ◽  
Angela Dispenzieri ◽  
Paul Kurtin ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Plasma Cell ◽  
Light Chain ◽  
Plasma Cells ◽  
M Protein ◽  
Cell Content ◽  
Bone Marrow Plasma ◽  
M Spike

Abstract Smoldering multiple myeloma (SMM) is characterized by a serum M protein ≥ 3g/dL and/or 10% or more of plasma cells in the bone marrow. However, the definition is not standardized, and it is not known whether both serum M protein levels and bone marrow plasma cell counts are necessary for diagnosis or if one parameter is sufficient. We reviewed the medical records and bone marrows of all patients from Mayo Clinic seen within 30 days of recognition of an IgG or IgA M protein ≥ 3g/dL or a bone marrow containing ≥ 10% plasma cells from 1970 to 1995. This allows for a minimum potential follow-up of 10 years. Patients with end-organ damage at baseline from plasma cell proliferation, including active multiple myeloma (MM) and primary amyloidosis (AL) and those who had received chemotherapy were excluded. A differential of the bone marrow aspirate coupled with the bone marrow biopsy morphology and immunohistochemistry using antibodies directed against CD138, MUM-1 and Cyclin D1 were evaluated in every case in order to estimate the plasma cell content. In all, 301 patients fulfilled either of the criteria for SMM. Their median age was 64 years and only 3% were less than 40 years of age; 60% were male. The median hemoglobin value was 12.9 g/dL; 7% were less than 10 g/dL, but the anemia was unrelated to plasma cell proliferation. IgG accounted for 75%, IgA 22%, and biclonal proteins were found in 3%. The serum light-chain was κ in 67% and λ in 33%. The median serum M spike was 2.9 g/dL; 11% were at least 4.0 g/dL. Uninvolved serum immunoglobulins were reduced in 81%; only 1 immunoglobulin was reduced in 31% and both were decreased in 50%. The urine contained a monoclonal κ protein in 36% and λ in 18% and 46% were negative. The median size of the urine M spike was 0.04 g/24h; only 5 (3%) were > 1 g/24h. The median bone marrow plasma cell content was 15 – 19%; 10% had less than 10% plasma cells, while 10% had at least 50% plasma cells in the bone marrow. Cyclin D-1 was expressed in 17%. Patients were categorized into 3 groups: Group 1, serum M protein ≥ 3g/dL and bone marrow containing ≥ 10% plasma cells (n= 113, 38%); Group 2, bone marrow plasma cells ≥ 10% but serum M protein < 3g/dL (n= 158, 52%); Group 3, serum M protein ≥ 3g/dL but bone marrow plasma cells < 10% (n= 30, 10%). During 2,204 cumulative years of follow-up 85% died (median follow-up of those still living 10.8 years), 155 (51%) developed MM, while 7 (2%) developed AL. The overall rate of progression at 10 years was 62%; median time to progression was 5.5 yrs. The median time to progression was 2.4, 9.2, and 19 years in groups 1, 2, and 3 respectively; correspondingly at 10 years, progression occurred in 76%, 59%, and 32% respectively. Significant risk factors for progression with univariate analysis were serum M spike ≥ 4g/dL (p < 0.001), presence of IgA (p = 0.003), presence of urine light chain (p = 0.006), presence of λ urinary light chain (p = 0.002), bone marrow plasma cells ≥ 20% (p < 0.001) and reduction of uninvolved immunoglobulins (p < 0.001). The hemoglobin value, gender, serum albumin, and expression of cyclin D-1 were not of prognostic importance. On multivariate analysis, the percentage of bone marrow plasma cells was the only significant factor predicting progression to MM or AL.

An In Vivo Model To Investigate the Identity of the Cell-of-Origin of Multiple Myeloma.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1534-1534
Author(s):  
Fotios A. Asimakopoulos ◽  
Harold E. Varmus
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Transcription Factor ◽  
Plasma Cell ◽  
Germinal Center ◽  
Plasma Cells ◽  
Lymphoid Tissues ◽  
Cell Of Origin ◽  
Dark Zone ◽  
Bone Marrow Plasma

Abstract Multiple myeloma (MM) is characterized by monoclonal expansion of bone marrow plasma cells. However, long-lived plasma cells resident in the marrow are terminally differentiated and possess a limited replicative lifespan; it is puzzling how they could be the source of aggressive and relapsing neoplasms. We postulate that the myeloma clonogenic progenitor may reside in a more immature compartment with greater self-renewal capacity, most probably a cell participating in, or having shortly exited the germinal center reaction. However, it is unclear whether critical mutations occur in the target cell prior to, or following commitment to the plasma cell fate. To investigate the nature of the MM cell-of-origin, we have created a novel flexible mouse model system that enables the delivery of stochastic, sequential, somatic mutations to precisely defined compartments of the germinal center in secondary lymphoid tissues. To this end, we have used BAC transgenic technology to express distinct types of avian leukosis virus (ALV) receptors, TVA and TVB, in the expanding centroblast of the dark zone and the committed plasmablast of the light zone, respectively. Mammalian tissues are refractory to transduction by retroviruses of the ALV family unless they ectopically express the cognate avian-derived receptors. Thus, the coding sequences for the TVA receptor, fused to a fluorescent protein tag were placed under the control of transcription factor A-myb, expressed in centroblasts of the dark zone. Similarly, sequences encoding a fluorescent-tagged TVB receptor were placed under the control of transcription factor Blimp1, expressed in the earliest committed plasmablasts as well as mature plasma cells. Analysis of the Blimp1: TVB mice showed that expression of the avian retroviral receptor in the hematopoietic system is limited to the light zone of germinal centers, extrafollicular collections of CD138+ cells in the spleen and lymph nodes as well as long-lived bone marrow plasma cells. Analysis of A-myb: TVA transgenic mice is currently underway. The system permits the introduction of a variety of molecular lesions to specific plasma cell precursors via retroviral transduction of oncogenes, shRNAs against tumor suppressor genes or inducible regulators of gene expression in an attempt to re-create the sequence of molecular lesions leading to MM in the relevant cellular context.

Bone Marrow Neovascularization, Plasma Cell Angiogenic Potential, and Matrix Metalloproteinase-2 Secretion Parallel Progression of Human Multiple Myeloma

Blood ◽  
1999 ◽  
Vol 93 (9) ◽  
pp. 3064-3073 ◽  
Author(s):  
Angelo Vacca ◽  
Domenico Ribatti ◽  
Marco Presta ◽  
Monica Minischetti ◽  
Monica Iurlaro ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
Matrix Metalloproteinase ◽  
Plasma Cell ◽  
Plasma Cells ◽  
Cam Assay ◽  
Angiogenic Activity ◽  
Angiogenic Potential ◽  
Cell Extracts ◽  
Bone Marrow Plasma

Abstract To assess whether the progression of plasma cell tumors is accompanied by angiogenesis and secretion of matrix-degrading enzymes, bone marrow biopsy specimens from 20 patients with monoclonal gammopathy of undetermined significance (MGUS), 18 patients with nonactive multiple myeloma (MM), and 26 patients with active MM were evaluated for their angiogenic potential and matrix-metalloproteinase (MMP) production. A fivefold increase of the factor VIII+microvessel area was measured by a planimetric method of point counting in the bone marrow of patients with active MM as compared with nonactive MM and MGUS patients (P < .01). When serum-free conditioned media (CM) of plasma cells isolated from the bone marrow of each patient were tested in vivo for their angiogenic activity in the chick embryo chorioallantoic membrane (CAM) assay, the incidence of angiogenic samples was significantly higher (P< .01) in the active MM group (76%) compared with nonactive MM (33%) and MGUS (20%) groups. Moreover, a linear correlation (P < .01) was found between the extent of vascularization of the bone marrow of a given patient and the angiogenic activity exerted in the CAM assay by the plasma cells isolated from the same bone marrow. In vitro, a significantly higher fraction of the plasma cell CM samples from the active MM group stimulated human umbilical vein endothelial cell (HUVEC) proliferation (53%, P < .01), migration (42%, P < .05), and/or monocyte chemotaxis (38%,P < .05) when compared with nonactive MM and MGUS groups (ranging between 5% and 15% of the samples). Also, immunoassay of plasma cell extracts showed significantly higher (P < .01) levels of the angiogenic basic fibroblast growth factor (FGF)-2 in the active MM patients than in nonactive MM and MGUS patients (153 ± 59, 23 ± 17, and 31 ± 18 pg FGF-2/100 μg of protein, respectively). Accordingly, neutralizing anti–FGF-2 antibody caused a significant inhibition (ranging from 54% to 68%) of the biological activity exerted on cultured endothelial cells and in the CAM assay by plasma cell CM samples from active MM patients. Finally, in situ hybridization of bone marrow plasma cells and gelatin-zymography of their CM showed that active MM patients express significantly higher (P < .01) levels of MMP-2 mRNA and protein when compared with nonactive MM and MGUS patients, whereas MMP-9 expression was similar in all groups. Taken together, these findings indicate that the progression of plasma cell tumors is accompanied by an increase of bone marrow neovascularization. This is paralleled by an increased angiogenic and invasive potential of bone marrow plasma cells, which is dependent, at least in part, by FGF-2 and MMP-2 production. Induction of angiogenesis and secretion of MMPs by plasma cells in active disease may play a role in their medullary and extramedullary dissemination, raising the hypothesis that angiostatic/anti-MMP agents may be used for therapy of MM.

scholarly journals Evidence for a bone marrow B cell transcribing malignant plasma cell VDJ joined to C mu sequence in immunoglobulin (IgG)- and IgA-secreting multiple myelomas.

1993 ◽  
Vol 178 (3) ◽  
pp. 1091-1096 ◽  
Author(s):  
P Corradini ◽  
M Boccadoro ◽  
C Voena ◽  
A Pileri
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
B Lymphocytes ◽  
Plasma Cell ◽  
Plasma Cells ◽  
Bone Marrow Cells ◽  
Indirect Evidence ◽  
Specific Marker

Multiple myeloma is a B cell malignancy characterized by the expansion of plasma cells producing monoclonal immunoglobulins (Ig). It has been regarded as a tumor arising at the B, pre-B lymphocyte, or even stem cell level. Precursor cells are presumed to proliferate and differentiate giving rise to the plasma cell clonal expansion. Antigenic features and specific Ig gene rearrangement shared by B lymphocytes and myeloma cells have supported this hypothesis. However, the existence of such a precursor is based upon indirect evidence and is still an open question. During differentiation, B cells rearrange variable (V) regions of Ig heavy chain genes, providing a specific marker of clonality. Using an anchor polymerase chain reaction assay, these rearranged regions from five patients with multiple myeloma were cloned and sequenced. The switch of the Ig constant (C) region was used to define the B cell differentiation stage: V regions are linked to C mu genes in pre-B and B lymphocytes (pre-switch B cells), but to C gamma or C alpha in post-switch B lymphocytes and plasma cells (post-switch B cells). Analysis of bone marrow cells at diagnosis revealed the presence of pre-switch B cells bearing plasma cell V regions still joined to the C mu gene. These cells were not identified in peripheral blood, where tumor post-switch B cells were detected. These pre-switch B cells may be regarded as potential myeloma cell precursors.

scholarly journals A novel membrane antigen selectively expressed on terminally differentiated human B cells

Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1922-1930 ◽  
Author(s):  
T Goto ◽  
SJ Kennel ◽  
M Abe ◽  
M Takishita ◽  
M Kosaka ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Plasma Cell ◽  
Peripheral Blood ◽  
Plasma Cells ◽  
Affinity Constant ◽  
Target Antigen ◽  
Specific Marker

Abstract A monoclonal antibody (MoAb) that defines a novel terminal B-cell- restricted antigen, termed HM1.24, was developed against a human plasma cell line. The MoAb, designated anti-HM1.24, reacted with five different human myeloma cell lines, as well as with monoclonal neoplastic plasma cells obtained from the bone marrow or peripheral blood of patients with multiple myeloma or Waldenstrom's macroglobulinemia. The HM1.24 antigen was also expressed by mature Ig- secreting B cells (plasma cells and lymphoplasmacytoid cells) but not by other cells contained in the peripheral blood, bone marrow, liver, spleen, kidney, or heart of normal individuals or patients with non- plasma-cell-related malignancies. The anti-HM1.24 MoAb bound to human myeloma RPMI 8226 cells with an affinity constant of 9.2 x 10(8) M-1, indicating approximately 84,000 sites/cell. By immunoprecipitation assay under reducing conditions, this MoAb identified a membrane glycoprotein that had a molecular weight of 29 to 33 kD. Our studies indicate that the HM1.24-related protein represents a specific marker of late-stage B-cell maturation and potentially serves as a target antigen for the immunotherapy of multiple myeloma and related plasma cell dyscrasias.

scholarly journals A novel membrane antigen selectively expressed on terminally differentiated human B cells

Blood ◽  
1994 ◽  
Vol 84 (6) ◽  
pp. 1922-1930 ◽  
Author(s):  
T Goto ◽  
SJ Kennel ◽  
M Abe ◽  
M Takishita ◽  
M Kosaka ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Bone Marrow ◽  
B Cells ◽  
B Cell ◽  
Plasma Cell ◽  
Peripheral Blood ◽  
Plasma Cells ◽  
Affinity Constant ◽  
Target Antigen ◽  
Specific Marker

A monoclonal antibody (MoAb) that defines a novel terminal B-cell- restricted antigen, termed HM1.24, was developed against a human plasma cell line. The MoAb, designated anti-HM1.24, reacted with five different human myeloma cell lines, as well as with monoclonal neoplastic plasma cells obtained from the bone marrow or peripheral blood of patients with multiple myeloma or Waldenstrom's macroglobulinemia. The HM1.24 antigen was also expressed by mature Ig- secreting B cells (plasma cells and lymphoplasmacytoid cells) but not by other cells contained in the peripheral blood, bone marrow, liver, spleen, kidney, or heart of normal individuals or patients with non- plasma-cell-related malignancies. The anti-HM1.24 MoAb bound to human myeloma RPMI 8226 cells with an affinity constant of 9.2 x 10(8) M-1, indicating approximately 84,000 sites/cell. By immunoprecipitation assay under reducing conditions, this MoAb identified a membrane glycoprotein that had a molecular weight of 29 to 33 kD. Our studies indicate that the HM1.24-related protein represents a specific marker of late-stage B-cell maturation and potentially serves as a target antigen for the immunotherapy of multiple myeloma and related plasma cell dyscrasias.

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