CD38-targeting antibodies in multiple myeloma: mechanisms of action and clinical experience

Introduction: Multiple myeloma (MM) is generally an incurable hematological malignancy with heterogeneous overall survival rates ranging from a few months to more than 10 years. Survival is especially poor for patients who developed disease that is refractory to immunomodulatory drugs and proteasome inhibitors.

Areas covered: This review will discuss the importance of CD38-targeting antibodies for the treatment of MM patients to improve their outcome.

Expert commentary: Intense immuno-oncological laboratory research has resulted in the development of functionally active monoclonal antibodies against cell surface markers present on MM cells. In this respect, CD38-targeting antibodies such as daratumumab, MOR202, and isatuximab, have high single agent activity in heavily pretreated MM patients by virtue of their pleiotropic mechanisms of action including Fc-dependent effector mechanisms and immunomodulatory activities. Importantly, CD38-targeting antibodies are well tolerated, with infusion reactions as most frequent adverse event. Altogether, this makes them attractive combination partners with other anti-MM agents. Daratumumab is already approved as monotherapy and in combination with lenalidomide-dexamethasone as well as bortezomib-dexamethasone in pretreated MM patients. Furthermore, results from studies evaluating CD38-targeting antibodies in newly diagnosed MM patients are also promising, indicating that CD38-targeting antibodies will be broadly used in MM, resulting in further improvements in survival.     

抗人CD38单克隆抗体的制备、鉴定及其功能的初步研究

目的：研制抗人CD38抗原分子的单克隆抗体,进一步研究其生物学功能。方法：采用高表达CD38抗原的Daudi细胞免疫Balb/c小鼠;取其脾细胞与SP2/0细胞融合;用间接免疫荧光法进行杂交瘤筛选;流式细胞术、免疫沉淀法与CD38分子原核表达产物的Western-blot分析鉴定单克隆抗体的特异性。以MTT（四甲偶氨唑盐）法检测单克隆抗体抑制细胞增殖以及介导补体杀伤靶细胞的功能。结果：获得了一株抗人CD38分子的单克隆抗体1C6,流式细胞术显示它具有CD38抗原特异的细胞反应谱,其识别的抗原分子质量为45000u。与CD38分子原核表达产物的Western-blot分析表明,其可特异识别CD38分子胞外结构域。MTT法显示其可介导补体杀伤靶细胞。结论：成功制备了抗人CD38分子的单克隆抗体,并进行了初步的功能研究。     

鼠抗人CD28功能性单克隆抗体的研制及其生物学特性的鉴定

以天然表达CD28分子的人多发性骨髓瘤(multiple myeloma,MM)细胞:XG-1为免疫原,常规免疫BALB/c小鼠,采用B淋巴细胞杂交瘤技术进行细胞融合,CD28转基因细胞株(T-28)及XG-1为抗体筛选阳性细胞株,经免疫荧光标记分析反复筛选和多次的克隆化培养,最终获得1株持续、稳定分泌鼠抗人CD28单克隆抗体的杂交瘤细胞株,命名为10F3。对这株单抗生物学功能的研究结果表明,这株抗体能特异性地识别人CD28分子和介导有效的共刺激信号,激发T细胞的活化和增殖。     

激发型CD28单抗诱导多发性骨髓瘤细胞凋亡的作用研究

为了探讨激发型CD2 8单抗诱导多发性骨髓瘤细胞凋亡的作用及其机制 ,在表达CD2 8分子的多发性骨髓瘤细胞U2 6 6和XG 1的培养体系中加入终浓度为 10 μg/ml的激发型CD2 8单抗 ,逐日观察和分析细胞的生长与增殖状况。结果显示 ,在加入激发型CD2 8单抗后 2 4h即可见细胞聚集且逐渐加剧 ,细胞的立体感和折光性逐渐减弱 ,细胞的生长与增殖抑制 ,台盼蓝着色阳性率增加 ;凝胶电泳的结果表明 ,多发性骨髓瘤细胞出现降解的DNA条带 ;透射电镜分析的结果显示 ,加入激发型CD2 8单抗培养 2 4～ 4 8h ,30 %以上的细胞出现核质边聚的凋亡早期的病理性改变 ,培养 72h后 ,5 0 %以上的细胞出现空泡及凋亡小体。提示激发型CD2 8单抗具有诱导表达CD2 8分子的多发性骨髓瘤细胞凋亡的作用。     

ICO-45 monoclonal antibodies to a new epitope of CD38 antigen

All-Union Oncologic Scientific Center, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR, N. N. Trapeznikov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 107, No. 6, pp. 729–731, June, 1989.     

Establishment of a monoclonal antibody to plasma cells: a comparison with CD38 and PCA-1

A new monoclonal antibody which recognizes plasma cells was developed by utilizing two myeloma cell lines, KMS12PE (12PE) and KMS12BM (12BM). established from the pleural of fusion and bone marrow, respectively, of the same patient. Since I2BM expresses CD20, CD38, and PCA-I antigens, while 12PE has lost CD20. 12PE is considered to be phenotypically more mature than 12BM. The 12PE cells were used to immunize a BALB/c mouse and a MoAb was produced which was more reactive to 12PE than to 12BM. Thus, a clone, D2, was obtained. On Western blotting, D2 detected a single band of 54 kD under both reduced and non-reduced conditions. This antigen was not detected by Western blotting in peripheral blood lymphocytes that had been stimulated with pokeweed mitogen (PWM) for 7 days or in those not so stimulated. On flow cytometry, D2 detected a myeloma cell line, RPMI 8226. Another myeloma cell line, U266, was negative for D2 antigen. Staining various cell lines by D2 and other antiplasma cell antibodies, PCA-1 and CD38, showed that D2 is distinct from PCA-1 and CD38. The fresh myeloma cells of 14 myeloma patients were stained by D2 and for other plasma cell antigens. D2 strongly stained three samples obtained from patients with clinically aggressive myeloma, while CD38 stained all cases except one. PCA-1 was positive in nine samples and negative in five. PCA-1 expression was observed in plasma cells obtained from pleural effusion and peripheral blood, while PCA-1-negative cases were not found in such samples, suggesting that PCA-I expression was related to extramedullary invasion. The morphology of the myeloma cells, classified according to Greipp's criteria, showed that there was no correlation between plasma cell antigen expression and plasma cell morphology. Analysis of D2 antigen expression should provide more information about the heterogeneity of myeloma cells.     

A Novel Anti-Human Syndecan-1（CD138） Monoclonal Antibody 4B3： Characterization and Application

Syndecan-1 （CD138）, a member of integral membrane heparin sulfate proteoglycans, is an essential matrix receptor for maintaining the normal morphological phenotypes. In this study, we generated a specific mouse anti-human syndecan-1 monoclonal antibody （mAb） 4B3 and identified it by competition assay with the available syndecan-1 mAb （BB4）. Stained by 4B3, the expression of syndecan-1 was detected on tumor cell lines, such as 8226, U266, XG-1, XG-2, Daudi and Jurkat. The expression was also found on neuron stem cells. It was established that 4B3 mAb could inhibit XG-1 and XG-2 proliferation. The data not only determined that 4B3 mAb was a functional anti-human syndecan-1 mAb, but also indicated that syndecan-1 might be a valuable surface antigen and play an important role in regulation of tumor pathology and differentiation of neural stem cells. This novel antibody 4B3 may be value of study of tumor proliferation/survival mechanism and contributes to diagnosis and treatment of diverse diseases. Cellular ＆ Molecular Immunology.     

Expression of CD5 and CD38 by human CD5− B cells: Requirement for special stimuli

In this study the mode of expression of CD5 by human tonsillar CD5^? B cells after stimulation with different agents was investigated. Resting B cells were separated into CD5⁺ and CD5^? cells and the two cell fractions exposed to phorbol 12-myristate 13-acetate (PMA). CD5^? B cells expressed CD5 and maximum CD5 expression was achieved after approximately 60 h of culture. Based upon the proportions of cells that express CD5 as well as those of the cells surviving in culture, it was calculated that 15–25 % of the total CD5^? B cells were induced to express CD5. Unlike CD5^? B cells, CD5⁺ B cells proliferated vigorously in response to PMA as assessed by [³H] thymidine incorporation and cell cycle analysis in vitro. However, the expression of CD5 by CD5^? B cells was not related to the selective expansion of some CD5⁺ B cells left over as contaminant cells since this occurred in the absence of cell proliferation. Upon exposure to PMA, CD5^? B cells remained in the G0-G1 phases of the cell cycle and did not express the Ki67 antigen or incorporate [³H] thymidine. Furthermore, mitomycin C treatment of the CD5^? B cells did not prevent CD5 expression. Phenotypic studies disclosed that CD5⁺ B cells but not CD5^? B cells expressed CD39. This finding offered the opportunity to carry out an additional control experiment. Separation of the two populations according to the expression of CD39 confirmed the finding obtained by fractionating the cells into CD5⁺ and CD5^? B cells. The cells induced to express CD5 also expressed CD38 that was not detected on resting CD5^? B cells. In this respect, the CD5^? B cells that converted into CD5⁺ cells (inducible CD5⁺ B cells) resembled the cells from the CD5⁺ B cell fractions that up-regulated CD5 and also expressed CD38 upon exposure to PMA alone. Another example of coordinate expression of these two antigens was the finding that exposure to PMA in the presence of recombinant interleukin-4 (rIL-4) resulted in inhibition of the expression of CD5 and CD38. Although virtually all of the tonsillar CD5^? B cells expressed the CD69 activation marker, no cells other than those co-expressing CD5 and CD38 were induced to express CD5 by PMA alone. Resting CD5^? B cells failed to express CD5 and/or CD38 when cultured with PMA in the presence of EL4 T cells and IL-4-free T cell supernatants. Although this combination of stimuli induced a vigorous cell proliferation, the failure to express CD5 and CD38 was not related to cell cycling, since mitomicyn C-treated CD5^? B cells also failed to express CD5 or CD38 when exposed to PMA in the presence of EL4 cells with or without T cell supernatants. Thus, exposure to T cells alone was sufficient to down-regulate CD5 and CD38 expression. Collectively, the above findings indicate that mature CD5^? B cells can follow distinct pathways of differentiation depending upon the nature of the stimuli encountered, and that CD5 expression may identify a special B cell subset or a particular stage of B cell differentiation.     

CD38分子的表达及临床应用前景

CD38分子是单链II型跨膜糖蛋白,广泛表达于造血细胞及非造血细胞系,具有许多复杂而又独特的生物学特性及功能。近年来临床研究发现CD38分子是慢性B淋巴细胞白血病的预测因子,自身免疫反应性糖尿病的诊断指标,并可用于艾滋病及巨细胞病毒的检测及系统性红斑狼疮的病情监测。     

Dendritic cells and follicular dendritic cells express a novel ligand for CD38 which influences their maturation and antibody responses

CD38 is a cell surface molecule with ADP-ribosyl cyclase activity, which is predominantly expressed on lymphoid and myeloid cells. CD38 has a significant role in B-cell function as some anti-CD38 antibodies can deliver potent growth and differentiation signals, but the ligand that delivers this signal in mice is unknown. We used a chimeric protein of mouse CD38 and human immunogobulin G (IgG) (CD38-Ig) to identify a novel ligand for murine CD38 (CD38L) on networks of follicular dendritic cells (FDCs) as well as dendritic cells (DCs) in the spleen. Flow-cytometry found that all DC subsets expressed cytoplasmic CD38L but only fresh ex vivo CD11c+ CD11b- DCs had cell surface CD38L. Anti-CD38 antibody blocked the binding of CD38-Ig to CD38L, confirming the specificity of detection. CD38-Ig immuno-precipitated ligands of 66 and 130 kDa. Functional studies found that CD38-Ig along with anti-CD40 and anti-major histocompatibility complex (MHC) class II antibody provided maturation signals to DCs in vitro. When CD38-Ig was administered in vivo with antigen, IgG2a responses were significantly reduced, suggesting that B and T cells expressing CD38 may modulate the isotype of antibodies produced through interaction with CD38L on DCs. CD38-Ig also expanded FDC networks when administered in vivo. In conclusion, this study has identified a novel ligand for CD38 which has a role in functional interactions between lymphocytes and DCs or FDCs.     

CD38 ligation induces discrete cytokine mRNA expression in human cultured lymphocytes

Human CD38 is a surface glycoprotein expressed by different immuno-competent cells such as immature and activated lymphocytes, plasma cells and natural killer cells. It has recently been reported that the CD38 molecule exerts adenosine diphosphate ribosyl cyclase activity and is associated with distinct transmembrane signaling molecules. This study reports that ligation of CD38 by specific monoclonal antibodies (mAb) induces multiple cytokine mRNA expression in cultured peripheral blood mononuclear cells (PBMC). The mRNA for tumor necrosis factor-α, interleukin (IL)-1β, IL-6, granulocyte-macrophage colony-stimulating factor (GM-CSF) and IL-12 were always detected, whereas interferon-γ and IL-10 mRNA expression were seen in most, but not all PBMC cultures. Low levels of IL-2, IL-4 and IL-5 mRNA were also found. The key observation of this work is that CD38 ligation in PBMC induces a large spectrum of cytokines, many of which overlap with those induced via CD3 activation. The main differences between CD38 and CD3 activation are the low to undetectable levels of IL-2 mRNA, and the sustained IL-1β and IL-6 mRNA accumulation found in PBMC cultures following treatment with anti-CD38 mAb. Furthermore, PBMC proliferation was not found to be a prerequisite for CD38-mediated cytokine induction. Together, these results suggest that human CD38 activates a signaling pathway which leads to the induction of a discrete array of cytokines, and that this pathway only partially overlaps with that controlled by T cell receptor CD3.     

Role of CD38 in cell-cell interactions under conditions of endothelial dysfunction

We studied the role of receptor/ectoenzyme CD38 in the formation of endothelial damage and pathogenesis of endothelial dysfunction. CD38 was located in sites of protrusion of the outer cytoplasmic membrane. The majority of CD38⁺ accumulation sites coincided with the protrusion pole, while in some cells expression of CD38 was spread along the entire cell membrane surface or located on the pole opposite to the protrusion. We hypothesized that these states reflect the processes of rafting and clustering of the receptor, which are essential for cell-cell interactions in the pathogenesis of endothelial dysfunction. __________ Translated from Byulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 145, No. 6, pp. 648–651, June, 2008     

Death of T cell precursors in the human thymus: a role for CD38

Thymic T cell maturation depends on interactions between thymocytes and cells of epithelial and hematopoietic lineages that control a selective process whereby developing T cells with inappropriate or self-reactive receptors die. Molecules involved in this process are the TCR expressed on thymocytes together with the CD3 complex and MHC-peptide on accessory cells. However, other molecules may favor or prevent death of thymocytes, thus playing a role in selection. CD38 is expressed by the majority of human thymocytes, mainly at the double-positive (DP) stage. In contrast, CD38 is not found on subcapsular double-negative (DN) thymocytes and on a proportion of medullary single-positive (SP) thymocytes. CD38 enhances death of thymocytes when it is cross-linked by goat anti-mouse (GAM) antiserum or by one of its ligands, CD31, expressed by thymic epithelial cells or transfected into murine fibroblasts (L cells). As most thymocytes are at an intermediate (DP) stage of development, it is likely that these cells are most vulnerable to death mediated via MHC-peptide-TCR interactions that is increased by CD38 cross-linking. DN and SP thymocytes are refractory to CD38-induced apoptosis. Accessory molecules, e.g. CD38, are expressed during thymic cell maturation and their presence is relevant for the survival or death of DP T cells in the course of selection. Based on our data, CD38 enhances thymocyte death by interacting with CD31 expressed by accessory cells. In addition, CD28 expression on developing thymocytes also appears to play a role for their selection and it synergizes with CD38 to induce apoptosis of DP thymocytes.     

Zap-70 and CD38 as predictors of IgVH mutation in CLL

Zeta-chain (TCR)-associated protein kinase 70 kDa (Zap-70) and CD38 expression may be of prognostic significance in chronic lymphocytic leukemia (CLL). Previous studies indicate that Zap-70 and CD38 are usually positive in cases of CLL with unmutated immunoglobulin variable region genes (IgVH) and may be used to predict IgVH mutation status and prognosis. Usually cases of CLL positive for Zap-70 or CD38 indicate a worse prognosis. In the present investigation, 47 cases of CLL were evaluated for CD38 expression, and 17 cases were evaluated for both Zap-70 and CD38 expression. Of the 47 cases, 19 (40.4%) positively expressed CD38. Of the 17 cases evaluated for Zap-70, 11 (64.7%) were positive for Zap-70, while only 6 (35.3%) were positive for CD38 expression; the remaining cases were negative for CD38. The results of this study show that Zap-70 expression may be a better indicator of the mutational status of IgVH and prognosis of CLL than CD38 expression. In addition, CD38 negativity does not necessarily indicate that IgVH mutation has occurred. These data point to the need for a more extensive study to evaluate the significance of Zap-70 and CD38 expression as indicators of IgVH mutation status and prognosis of CLL patients.     

Prognostic Values of CD38+CD101+PD1+CD8+ T Cells in Pancreatic Cancer

Programmed death-1 (PD-1), a key immune checkpoint molecule, has been developed as an oncotherapy target for various carcinomas. However, treatment with anti-PD-1 elicited only a minimal effect in pancreatic ductal adenocarcinoma (PDAC). Subsequent studies revealed the existence of a subset of PD-1⁺ T cells coexpressing CD38 and CD101, representing a fixed dysfunctional subpopulation that are not able to be rescued by anti-PD-1 immunotherapy. However, whether this subpopulation of PD-1 expressing CD8⁺ T cells could be useful in predicting PDAC stage or prognosing survival is unknown. In this study, we used flow cytometry and immunofluorescence assay to analyze the expression of CD38 and CD101 in 183 clinical PDAC samples, including 84 of peripheral blood and 99 of surgical tissues. High coexpression of CD38/CD101 on peripheral PD-1⁺CD8⁺ T cells or tumor-infiltrating lymphocytes (TILs) was found to be most significantly correlated with Tumor/Node/Metastasis (T/N/M) classification and clinical stage, in contrast PD-1⁺CD8⁺ T cells could not correlate with T classification. CD38/CD101 co-repression on TILs also correlated with the poor survival in these PDAC patient samples. Our data suggest that CD38/CD101 might represent a more helpful biomarker than PD-1 alone for diagnosis and prognosis of PDAC.     

人CD38分子研究进展

人CD38分子是一种Ⅱ型跨膜糖蛋白,广泛表达于造血细胞及非造血细胞系。CD38分子的胞外结构域与核糖核苷二磷酸(ADPR)酶家族同源,与人及鼠的某些蛋白分子也具有明显的结构与功能上的同源性,提示这些分子可能代表一个新的蛋白分子家族。近年发现CD38分子具有许多复杂而又独特的生物学特性及功能。本文就CD38分子的结构、表达、功能特点及其配体分子予以简要综述。     

人CD38抗原胞外段基因克隆及表达

目的 克隆并表达人CD38抗原分子的胞外估基因。方法 采用RT－PCR法，从高表达CD38抗原的Daudi细胞系中，扩增CD38全长cDNA，并将其插入pGEM-T载体中。重新设计引物，从重组pGEMT载体中，扩增CD38抗体分子的胞外段基因，再亚克隆到表达载体pET28a( )，转化大肠杆菌BL21，用IPTG诱导表达。结果 经酶切鉴定及序列分析表明，克隆的CD38外段基因的序列与文献^[1,2]的报道完全一致。将该片段亚克隆到表达载体pET28a( ) ,经IPTG诱导在大肠杆菌BL21中获得表达。结论 获得了人CD38抗原分子胞外段基因及其原核表达产物，对进一步制备单克隆抗体，研究CD38分子的功能具有重要的意义。     

CD154 cDNA克隆、单克隆抗体制备及特异性鉴定

本研究目的是获得特异性抗人CD15 4单克隆抗体。利用特异引物 ,通过RT PCR从人外周血淋巴细胞中扩增出编码CD15 4分子的cDNA全长 ,将其克隆在谷胱甘肽巯基转移酶 (GST )融合蛋白表达载体pGEX4T 3中 ,转染大肠杆菌Jm10 9经诱导获得GST CD15 4表达。融合蛋白经分离纯化后 ,免疫Balb/c小鼠 ,应用杂交瘤技术 ,通过ELISA双筛 ,得到 2株抗CD15 4单抗 (1D3和 5H4)。其亚型分别是IgG2a和IgG1。又将CD15 4cDNA全长构建真核表达载体pcDNA3 CD15 4,并转染COS细胞 ,以G418筛选后 ,经RT PCR结果证实pcDNA3 CD15 4已成功转染COS细胞。所获单抗对转染CD15 4的COS细胞和刺激活化的人淋巴细胞有特异性结合反应 ,为进一步研究单抗功能奠定了实验基础。     

Monoclonal antibodies recognizing CD5, CD10 and CD23 in formalin-fixed, paraffin-embedded tissue: production and assessment of their value in the diagnosis of small B-cell lymphoma

AIMS: Assessment of the expression of antigens CD5, CD10 and CD23 can be of value in the differential diagnosis of small B-cell lymphoma. Correct subclassification is important since optimal treatment regimes differ between the subtypes. The aim of this study was to generate monoclonal antibodies recognizing these antigens in paraffin-embedded tissue and to assess their efficacy using a panel of cases of small B-cell lymphoma of various subtypes. METHODS AND RESULTS: For each antibody synthetic recombinant protein and conventional murine hybridoma technology was employed. Monoclonal antibodies effective in formalin-fixed, paraffin-embedded tissue were successfully generated, designated NCL-CD5-4C7, NCL-CD10-270 and NCL-CD23-1B12, respectively. A series of 58 cases of small B-cell lymphoma including examples of each subtype (lymphocytic, follicle centre cell, mantle cell, marginal zone and lymphoplasmacytoid) was assembled and immunostaining for the respective antigens carried out using the monoclonal antibodies produced. Our results indicate that the antibodies are specific for their respective antigens and give the predicted phenotypic profile in the small B-cell lymphoma subtypes. CONCLUSIONS: These novel monoclonal antibodies may be of value in routine diagnostic practice.     

肝肾移植术后巨细胞病毒感染者T细胞表面CD38的动态变化

目的动态监测肝肾移植术后巨细胞病毒(CMV)感染者T细胞表面CD38表达水平的变化。方法将研究对象的淋巴细胞与相应荧光标记的单克隆抗体反应,经洗涤、固定后用流式细胞仪检测T细胞表面CD38的表达量,健康对照组采血1次、稳定组术前及术后各采血1次、巨细胞病毒感染组受者分不同时间段采血。结果健康成人淋巴细胞表面CD38的表达量为(642.1±107.3)细胞,在不同性别及年龄组间差异无统计学意义(P>0.05);肝、肾移植感染组受者因CMV病毒感染发病时,CD38的表达量显著增加,与术前比较差异有统计学意义(P<0.01);抗感染治疗1周后,CD38的表达量逐渐下降,与感染时比较差异有统计学意义(P<0.01);在非病毒感染的移植受者CD38的表达水平不增高;CMV病毒感染组的患者在临床出现CMV感染症状前CD38+CD8+的表达水平已经增高,至治疗3个月以后由于体内CMV抗原的存在,CD38的表达水平仍然超出健康成人。结论双色流式细胞术定量分析淋巴细胞表面CD38+CD8+的表达水平对于监测CMV感染是较灵敏且特异的指标之一,在减少患者的医疗费用、评估治疗效果中具有重要的意义。