Immunoglobulin M Expression Research Articles

Carotenoids act on coloration and increase immunity and antioxidant activity in the novel “Yongzhang Golden turtle” strain of Pelodiscus sinensis

The body color of aquatic products is a key indicator that aquaculture practitioners use to evaluate health status and consumers use to judge quality. Carotenoids are natural pigments that are mainly pigmented compounds responsible for red, yellow, and orange coloration. They have important functions, such as immune and antioxidant modulation. Recently, a novel strain of Pelodiscus sinensis with bright yellow color, named the Yongzhang golden turtle (YGT), was obtained through selective breeding. However, the actions of carotenoids on its coloration, antioxidant activities and immune competence have not been investigated yet. In this study, we examined the concentration of carotenoids in the skin and calipash of the atrovirens wild-type turtle (AWT) and YGT by spectrophotometry and found that the concentration of carotenoids in the YGT was significantly higher than that in the AWT. Then, we measured relevant antioxidant activity indicators, including total antioxidant capacity (T-AOC) and malondialdehyde (MDA), by commercial kits in the YGT and AWT, identifying higher activities of T-AOC in the YGT compared with those in the AWT, while MDA contents were decreased in the YGT compared to those in the AWT. We quantified the immune competence of the YGT and AWT using plasma bacteria-killing ability (BKA) and immunoglobulin M (IgM) expression. Compared to plasma from the AWT, that of the YGT showed higher antibacterial activity against Escherichia coli, Aeromonas hydrophila, Staphylococcus aureus, Salmonella typhimurium, and Citrobacter freundii. However, there was no difference in IgM expression between the YGT and AWT. Correlation analysis suggested that carotenoids concentration were positively associated with T-AOC and BKA, and negatively associated with MDA. In conclusion, the bright yellow color of YGT was mainly caused by carotenoids, which could enhance the antioxidant capacity and immune competence. Therefore, the YGT, with yellow coloration, possesses a high ornamental value and is much better in quality than the AWT.

Human transitional and IgMlow mature naïve B cells preserve permissive B-cell receptors.

The level of immunoglobulin M (IgM) displayed on the surface of peripheral blood B cells exhibits a broad dynamic range and has been associated with both development and selection. To determine whether IgM surface expression associates with distinct immunoglobulin heavy‐chain (IGH) repertoire properties, we performed deep IgM sequencing of peripheral blood transitional and mature naïve B cells in the upper and lower quartiles of surface IgM expression for 12 healthy donors. Mature naïve B cells within the lowest quartile for surface IgM expression displayed more diverse IGH features including increased complementarity‐determining region 3 length, IGHJ6 segment usage and aromatic amino acids compared with mature naïve B cells with high surface IgM. There were no differences between IGH repertoires for transitional B cells with high or low surface IgM. These findings suggest that a selection checkpoint during progression of transitional to mature naïve B cells reduces the breadth of the IGH repertoire among high surface IgM B cells but that diversity is preserved in B cells expressing low levels of surface IgM.

CD10+ Cells and IgM in Pathogen Response in Lumpfish (Cyclopterus lumpus) Eye Tissues.

Lumpfish (Cyclopterus lumpus), a North Atlantic “cleaner“ fish, is utilized to biocontrol salmon louse (Lepeophtheirus salmonis) in Atlantic salmon (Salmo salar) farms. Lumpfish require excellent vision to scan for and eat louse on salmon skin. The lumpfish eye immune response to infectious diseases has not been explored. We examined the ocular response to a natural parasite infection in wild lumpfish and to an experimental bacterial infection in cultured lumpfish. Cysts associated with natural myxozoan infection in the ocular scleral cartilage of wild adult lumpfish harbored cells expressing cluster of differentiation 10 (CD10) and immunoglobulin M (IgM). Experimental Vibrio anguillarum infection, which led to exophthalmos and disorganization of the retinal tissues was associated with disruption of normal CD10 expression, CD10+ cellular infiltration and IgM expression. We further describe the lumpfish CD10 orthologue and characterize the lumpfish scleral skeleton in the context of myxozoan scleral cysts. We propose that lumpfish develop an intraocular response to pathogens, exemplified herein by myxozoan and V. anguillarum infection involving novel CD10+ cells and IgM+ cells to contain and mitigate damage to eye structures. This work is the first demonstration of CD10 and IgM expressing cells in a novel ocular immune system component in response to disease in a teleost.

Cutaneous Involvement by Mantle Cell Lymphoma: Expanding the Spectrum of Histopathologic Findings in a Series of 9 Cases

Mantle cell lymphoma (MCL) is an aggressive B-cell neoplasm with cutaneous involvement in ∼1% of cases. We present a single institutional series of nine patients (12 specimens) with cutaneous involvement by systemic MCL and review the clinicopathologic features. Six males and 3 females (age range 55-87 years) were included. Sites of involvement were head and neck (n = 3), trunk (n = 5), and extremities (n = 4). Histopathologically, 3 showed classic cytomorphology, 2 were blastoid, 3 pleomorphic, and 1 showed features resembling marginal zone lymphoma. Two cases presented with cutaneous lesions as the first tissue manifestation of the disease. A second malignancy was identified in 3/9 cases (2 melanomas and 1 papillary thyroid carcinoma). In one patient, MCL was juxtaposed with metastatic melanoma within the same biopsy specimen. Fluorescence in situ hybridization studies, when available, demonstrated the characteristic t(11,14) translocation. Direct immunofluorescence was performed on one case and showed immunoglobulin M (IgM) expression on the tumor cells. Follow-up was available in 7 cases (mean 42 months, range 6-78 months) and revealed death from disease for 6 patients that occurred within 1 week to 11 months (mean 4 months) after cutaneous involvement. In our series, 6/9 cases demonstrated blastoid, pleomorphic, or marginal zone lymphoma-like morphologies that could potentially mimic other hematolymphoid neoplasms. MCL may show surface IgM expression on DIF or may occur in association with other solid tumors. Immunohistochemistry for cyclin D1 and/or SOX-11 may be helpful for diagnosis, and imaging studies may be necessary to detect systemic involvement when cutaneous involvement is the first manifestation of the disease.

Class B CpG-ODN2006 is highly associated with IgM and antimicrobial peptide gene expression through TLR9 pathway in yellowtail Seriola lalandi

The purpose of this study was to characterize the TLR9 gene from yellowtail (Seriola lalandi) and evaluate its functional activity using the class B Cytosine-phosphate-guanine-oligodeoxynucleotide2006 (CpG-ODN2006) in an in vivo experiment after one-week immunostimulation. The gene expressions of TLR9, Immunoglobulin M (IgM), antimicrobial peptides and cytokines were evaluated by real time PCR, and humoral immune parameters were analyzed in serum. The TLR9 nucleotide sequence from yellowtail was obtained using the whole-genome shotgun sequencing method and bioinformatics tools. The yellowtail full-length cDNA sequence of SlTLR9 was 3789 bp in length, including a 66-bp 5′-untranslated region (UTR), a 3′-UTR of 528 bp, and an open reading frame (ORF) of 3192 bp translatable to 1064 amino acid showing a high degree of similarity with the counterparts of other fish species and sharing common structural architecture of the TLR family, including LRR domains, one C-terminal LRR region, and a TIR domain. Gene expression studies revealed the constitutive expression of TLR9 mRNA in all analyzed tissues; the highest levels were observed in intestine, liver and spleen where they play an important role in the fish immune system. The expression levels of TLR9 after B class CpG-ODN2006 (the main TLR9-agonist) was significantly up-regulated in all analyzed tissues, with the high expression observed in spleen followed by intestine and skin. The CpG-B has been shown as a potent B cell mitogen, and interestingly, IgM mRNA transcript was up-regulated in spleen and intestine, which was highly correlated with TLR9 after CpG-ODN2006 stimulation. The antimicrobial peptides, piscidin and NK-lysine, were up-regulated in spleen and gill after CpG-ODN2006 injection with a high correlation (r ≥ 0.82) with TLR9 gene expression. Cytokine genes were up-regulated in spleen, intestine and skin after CpG-ODN was compared with the control group. No significant correlation was observed between TLR9 and IL-1β, TNF-α and Mx gene expressions. The results showed that CpG-ODN2006 intraperitoneal injection enhanced lysozyme, peroxidase and superoxide dismutase activities in serum and demonstrated that CpG-ODN2006 can induce a specific immune response via TLR9 in which IgM and antimicrobial peptides must have an important role in the defense mechanisms against infections in yellowtail.

Effect of electroacupuncture at Huantiao (GB 30) and Weizhong (BL 40) on serum IgG and IgM in rabbits with lumbar intervertebral disc herniation

To observe the effect of electroacupuncture (EA) at Huantiao (GB 30) and Weizhong (BL 40) on thigmesthesia, gait function, and expression levels of serum immunoglobulin G (IgG) and immunoglobulin M (IgM) in rabbits with lumbar intervertebral disc herniation (LIDH). Forty healthy New Zealand rabbits were randomly divided into a blank control group, a model group, an EA at acupoint group and an EA at non-acupoint group, with 10 rabbits in each group. The LIDH pathological model of rabbit was established using the self-made LIDH model maker. The thigmesthesia and gait function of rabbits were recorded by Siegal method. The serum IgG and IgM expression levels were detected by enzyme-linked immunosorbent assay. EA at Huantiao (GB 30) and Weizhong (BL 40) could improve the clinical symptoms of thigmesthesia and gait function, and inhibit the expressions of serum IgG and IgM in the LIDH rabbits, which were significantly different compared with those in the model group and EA at non-acupoint group. EA at Huantiao (GB 30) and Weizhong (BL 40) can improve the clinical symptoms of LIDH rabbits, which is associated with inhibition of the serum IgG and IgM expressions and reduction of the immunoinflammatory factor release. This may be one of the mechanisms of EA at Huantiao (GB 30) and Weizhong (BL 40) in the treatment of LIDH.

In vitro and in vivo evidence for uncoupling of B-cell receptor internalization and signaling in chronic lymphocytic leukemia.

B-cell receptor activation, occurring within lymph nodes, plays a key role in the pathogenesis of chronic lymphocytic leukemia and is linked to prognosis. As well as activation of downstream signaling, receptor ligation triggers internalization, transit to acidified endosomes and degradation of ligand-receptor complexes. Herein, we investigated the relationship between these two processes in normal and leukemic B cells. We found that leukemic B cells, particularly anergic cases lacking the capacity to initiate downstream signaling, internalize and accumulate ligand in acidified endosomes more efficiently than normal B cells. Furthermore, ligation of either surface CD79B, a B-cell receptor component required for downstream signaling, or surface Immunoglobulin M (IgM) by cognate agonistic antibody, showed that the two molecules internalize independently of each other in leukemic but not normal B cells. Since association with surface CD79B is required for surface retention of IgM, this suggests that uncoupling of B-cell receptor internalization from signaling may be due to the dissociation of these two molecules in leukemic cells. A comparison of lymph node with peripheral blood cells from chronic lymphocytic leukemia patients showed that, despite recent B-cell receptor activation, lymph node B cells expressed higher levels of surface IgM. This surprising finding suggests that the B-cell receptors of lymph node- and peripheral blood-derived leukemic cells might be functionally distinct. Finally, long-term therapy with the Bruton’s tyrosine kinase inhibitors ibrutinib or acalabrutinib resulted in a switch to an anergic pattern of B-cell receptor function with reduced signaling capacity, surface IgM expression and more efficient internalization.

Effect of ammonia-N on histology and expression of immunoglobulin M and component C3 in the spleen and head kidney of Pelteobagrus vachellii

Ammonia-N is toxic to many aquatic animals and serves as a key stress factor in aquatic environments. The effects of ammonia-N stress on the immune response of darkbarbel catfish Pelteobagrus vachellii were investigated in this study. Changes in overall histology, and in the expression of complement C3 and immunoglobulin M (IgM) in spleen and head kidney, and lysozyme and C3 in serum, were measured in 1 and 5mg/L ammonia-N. Hyperemia, melano-macrophage assembly and loose splenosis were evident in spleen tissue. Both lysozyme and component C3 were significantly reduced in serum (P<0.05) under both stress treatments, although lysozyme was increased slightly at 24h in the 1mg/L treatment. C3 mRNA expression increased at 6h in spleen and 6–12h in head kidney then decreased rapidly (P<0.05), although C3 mRNA recovered to control levels in spleen at 96h after the 1mg/L treatment (P>0.05). IgM expression also increased significantly at 6–12h in spleen and 6–24h in head kidney after the 1mg/L treatment (P<0.05). A similar overall pattern were observed with 5mg/L ammonia (P<0.05); IgM mRNA expression was elevated at 6h in spleen and 6–12h in head kidney (P<0.05) then decreased to levels below controls (P<0.05). These results suggest exposure to 5mg/L ammonia-N could damage the histological structure of spleen, diminish lysozyme and component C3 serum content, and suppress C3 and IgM expression in spleen and head kidney.

IgM as a novel predictor of disease progression in secondary focal segmental glomerulosclerosis.

AimTo determine the role of immunoglobulin M (IgM) deposits in clinical manifestations, disease outcome, and treatment response of idiopathic and secondary focal segmental glomerulosclerosis (FSGS).MethodsKidney biopsy specimens of 171 patients diagnosed with FSGS (primary and secondary) and 50 control patients were retrospectively included in the study. For each patient, clinical and outcome data were obtained and compared to morphological parameters, including immunofluorescence analysis of mesangial IgM and complement 3 (C3) deposits analyzed on kidney biopsy samples.ResultsThere were significant positive correlations between IgM and C3 deposition in secondary FSGS (P < 0.001) and between IgM and mesangial deposits detected by electron microscopy in secondary FSGS (P = 0.015), which indicated that higher IgM deposition correlated with higher C3 deposition and mesangial deposits only in secondary FSGS. Patients with secondary FSGS and the deposition of IgM showed inferior renal outcomes at earlier time points in comparison with patients with negative IgM expression (P = 0.022).ConclusionsWe detected a positive correlation between IgM and C3 in secondary FSGS. The association between IgM deposition and worse renal outcome in secondary FSGS indicates that IgM may play a role in the progression of this disease.

Association of apoptosis inhibitor of macrophage (AIM) expression with urinary protein and kidney dysfunction

Apoptosis inhibitor of macrophage (AIM) expressed on macrophages prolongs inflammation by protecting macrophages from apoptosis. Most circulating AIM co-exists with immunoglobulin M (IgM). AIM's pathophysiological role in relation to IgM remains unclear. Here we evaluated the glomerular expression/deposition of AIM and IgM in the kidney using immunohistochemistry and its associations with clinical manifestations in 43 patients with biopsy-confirmed kidney diseases. Kidney biopsy tissue from all patients was immunostained for AIM and IgM. Staining patterns and percent stained areas within the glomeruli were determined. Cells expressing AIM were identified by co-staining with macrophage and endothelial cell surface markers. Correlations between staining results and clinical parameters were evaluated using univariate and multivariate analyses. AIM was deposited in various areas, such as mesangial and capillary area. A part of AIM expression was localized to CD68-positive macrophages in the glomerulus. Amount of glomerular expression was positively correlated with urinary protein in patients with severe proteinuria (urinary protein ≥0.5g/day) and kidney dysfunction [estimated glomerular filtration ratio (eGFR) <60ml/min/1.73m2]. Urinary protein was higher in patients exhibiting overlapping glomerular expression of AIM and IgM. Annual eGFR decline rate negatively correlated with AIM-positive area. AIM-positive area and initial serum creatinine were independently associated with decreased kidney function. AIM expression in the kidney was associated with urinary protein and decline in kidney function. Co-expression with IgM appeared to exacerbate AIM's deleterious effects on kidney function. Combined glomerular AIM and IgM expression is a candidate prognostic index for kidney disease.

Regulation of IgD Expression and Its Role in B Cell Transformation

A developing B lymphocyte first acquires expression of immunoglobulin M (IgM) at the immature stage, and along maturation into the transitional stage it starts to co-express another isotype-IgD. IgM and IgD are generated by alternative splicing of long primary RNA transcripts from the Ig heavy chain (Igh) locus, so that they share the N-terminal antigen-binding variable region, but differ in the C-terminal constant region, encoded by Cμ or Cδ exons, respectively. Maturation into follicular (naïve) B cells, IgD levels surpass those of IgM; while upon antigen-stimulation and entering germinal center reaction, follicular B cells turn off IgD expression. Trans-acting factors have been proposed to control IgM and IgD expression since several decades ago. However, the first of such factors, Zfp318, was just reported last year (Enders et al. Proc Natl Acad Sci USA 2014; Pioli et al. J Immunol 2014). Still, other factors and signaling cascades regulating IgD expression remain to be identified.In this context, we accidentally discovered that expression of the Epstein-Barr virus (EBV) oncoprotein latent membrane protein 1 (LMP1) in B cells specifically abolishes IgD but not IgM expression; LMP1 signaling suppresses IgD expression at the mRNA level. Using microarray we screened differentially expressed genes in LMP1-expressing versus normal mouse B cells, and then looked up these genes in ImmuGen database (http://www.immgen.org) to identify those whose expression patterns correlate with that of IgD at various B cell developmental stages. These analyses returned us two new candidates Rapgef4 and CD55, in addition to Zfp318. By CRISPR technology, we further demonstrated that mutation of Rapgef4 or CD55 in mature B cells results in downregulation of IgD but not IgM. To define their role in regulating IgD expression in vivo, mice carrying conditional null alleles Rapgef4F/F and CD55F/F, are being generated.The facts that IgD is an evolutionarily conserved Ig isotype and its expression is precisely regulated during B cell developmental and functional stages suggest an important role in B cell biology/function. Indeed, a recent study suggested that IgD, by sequestering CD19 coreceptor from IgM, might play a negative role in B cell receptor (BCR) signaling (Klasener et al. eLife 2014). Interestingly, flow cytometric analysis of 12 diffuse large B cell lymphoma (DLBCL)-like malignancies arising in our mouse model revealed that 10 cases are low/negative for IgD and the other 2 cases express intermediate levels of IgD, while they all express surface IgM or IgG (Zhang et al. Cell Rep 2015; data not shown); human DLBCLs often retain surface IgM expression (Wright et al. Proc Natl Acad Sci USA 2003; IgD expression data not available). Basing on aforementioned observations, we hypothesize that downregulation of IgD may be important for LMP1-induced B cell transformation and for DLBCL pathogenesis in general. Accordingly, in this work, we will reconstitute IgD expression in LMP1+ lymphoma cell lines (Zhang et al. Cell 2012), and determine if it suppresses lymphoma cell growth in vitro and in vivo. Similarly, we will reconstitute IgD expression in a few IgD- mouse DLBCL lines and monitor its impact on lymphoma growth. In addition, as we have 2 DLBCL lines expressing intermediate levels of IgD, we will use CRISPR technology to delete/mutate Cδ coding sequence in these lymphoma lines, and see if the mutated cells (losing IgD expression) outcompete the non-mutated cells.Overall, this work will lead to molecular insights into IgD regulation. It may also elucidate the functional significance of IgD downregulation in B cell lymphoma pathogenesis/maintenance, and guide therapy development targeting BCR signaling. DisclosuresNo relevant conflicts of interest to declare.

Responsiveness of B cells is regulated by the hinge region of IgD.

Mature B cells express immunoglobulin M (IgM)- and IgD-isotype B cell antigen receptors, but the importance of IgD for B cell function has been unclear. By using a cellular in vitro system and corresponding mouse models, we found that antigens with low valence activated IgM receptors but failed to trigger IgD signaling, whereas polyvalent antigens activated both receptor types. Investigations of the molecular mechanism showed that deletion of the IgD-specific hinge region rendered IgD responsive to monovalent antigen, whereas transferring the hinge to IgM resulted in responsiveness only to polyvalent antigen. Our data suggest that the increased IgD/IgM ratio on conventional B-2 cells is important for preferential immune responses to antigens in immune complexes, and that the increased IgM expression on B-1 cells is essential for B-1 cell homeostasis and function.

Transcription alteration of immunologic parameters and histopathological damage in common carp (Cyprinus carpio L.) caused by paraquat.

The toxic effects of paraquat (PQ) on the transcription of immunoglobulin M (IgM), complement C3 (C3), and lysozyme (LYZ) and the histopathological alteration of the liver, kidney, and spleen of common carp were evaluated by subacute exposure to 1.596 or 3.192 mg/L of PQ for 7 days. The results demonstrated that PQ exposure altered the transcription of IgM, C3, and LYZ. For example, IgM and C3 expression was generally downregulated, but LYZ was either down- or upregulated, suggesting that PQ may disturb the function of the fish immune system. The results of the histopathological examination revealed that the liver, kidney, and spleen of PQ-treated fish were injured. These injuries included cellular swelling, intracytoplasmic vacuolization, nucleus distortion, and pycnosis in the liver and spleen, and vacuolization of the renal parenchyma and intumescence of the renal tubule in the kidney. This finding indicates that PQ causes toxicity in common carp.

Single or combined effects of Lactobacillus sakei and inulin on growth, non-specific immunity and IgM expression in leopard grouper (Mycteroperca rosacea)

The aim of this study was to evaluate the single or combined effects of Lactobacillus sakei with inulin suitable for immunological in vivo studies in farmed fish. By in vitro assays, L. sakei strain 5-4 showed antibacterial activities against all assayed fish pathogens (except the Vibrio harveyi strain CAIM-1793). L. sakei was able to survive at high fish bile concentrations. Fermentation of the agave inulin resulted in a large increase in number of lactobacilli. For the in vivo study, fish were fed for 8 weeks four practical diets: control diet (control), L. sakei 5-4 (10(7) CFU/g), inulin (1% or 10 g/kg) and L. sakei + inulin (10(7) CFU/g + 10 g/kg). The weight gain showed clearly the synergistic effect of L. sakei 5-4 and inulin at 6 and 8 weeks of treatments. Leopard grouper fed with L. sakei alone or combined with inulin have significantly increased the assayed physiological and humoral immune parameters. By real-time PCR assays, the mRNA transcripts of immunoglobulin M (IgM) were found to be higher expressed in intestine, head kidney, mucus, gill, spleen and skin. Moreover, mRNA expression levels of IgM in head kidney and anterior intestine were measured by real-time PCR. L. sakei 5-4 and L. sakei + inulin supplemented diet up-regulated the expression of IgM at week 4 and 8 in intestine and head kidney, respectively. These results support the idea that the L. sakei 5-4 alone or combined with agave inulin improved growth performance and stimulates the immune system of leopard grouper.

Isolation of RAG-1 and IgM transcripts from the striped trumpeter (Latris lineata), and their expression as markers for development of the adaptive immune response

A partial sequence of the recombination activating gene-1 (RAG-1) and several full length sequences of the immunoglobulin M (IgM) heavy chain mRNA were obtained from the striped trumpeter (Latris lineata). The RAG-1 fragment consisted of 205 aa and fell within the core region of the open reading frame. The complete IgM heavy chain sequences translated into peptides ranging between 581 and 591 aa. Both genes showed good homology to other vertebrate sequences. The expression of the two genes was assessed throughout the early developmental stages of striped trumpeter larvae (5–100 dph) and used as markers to follow the ontogeny of the adaptive immune response. Using RT-PCR, RAG-1 mRNA expression was detectable at 5 dph and remained so until 80 dph, before becoming undetectable at 100 dph. IgM expression was also detectable at 5 dph, and remained so throughout. These patterns of expression may suggest that the striped trumpeter possess mature B cells with surface IgM at 100 dph. However, complete immunological competence is likely not reached until some time later. The early detection of IgM mRNA at 5 dph led to the investigation of its presence in oocytes. Both RAG-1 and IgM mRNA transcripts were detected in unfertilized oocytes, suggesting that they are maternally transferred. The biological significance of such a phenomenon remains to be investigated.

Recombinant IgM expression in mammalian cells: A target protein challenging biotechnological production

For many years, the potential of immunoglobulin M (IgM) antibodies was not fully understood because of characteristics different to the well-known immunoglobulin G type like low target affinity, cross reactivity and complex protein structure. In the meanwhile IgMs have been positively evaluated for their use as therapeutic agent in the mucosal environment but also in serum to eradicate upcoming tumor cells and invading antigens. Therefore IgM class of antibodies will play a significant role in clinical applications but also diagnosis in the future. To evaluate the full potential of this kind of antibody molecules large amounts of high quality product will be needed. In this review the focus is set on the biotechnological aspect of producing IgM class antibodies recombinantly in mammalian cells. Current achievements in expression and purification of this molecule are highlighted and compared.

Spontaneous Production of Immunoglobulin M in Human Epithelial Cancer Cells

It is well known that B-1 B cells are the main cell type that is responsible for the production of natural immunoglobulin M (IgM) and can respond to infection by increasing IgM secretion. However, we unexpectedly found that some epithelial cells also can express rearranged IgM transcript that has natural IgM characteristics, such as germline-encoded and restricted rearrangement patterns. Here we studied IgM expression in human non-B cells and found that IgM was frequently expressed by many human epithelial cancer cells as well as non-cancer epithelial cells. Moreover, CD79A and CD79B, two molecules that are physically linked to membranous IgM on the surface of B cells to form the B cell antigen receptor complex, were also expressed on the cell surface of epithelial cancer cells and co-located with IgM. Like the natural IgM, the epithelial cancer cell-derived IgM recognized a series of microbial antigens, such as single-stranded DNA, double-stranded DNA, lipopolysaccharide, and the HEp-2 cell antigen. More important, stimulation of the toll-like receptor 9 (TLR9), which mimics bacterial infection, substantially increased the secretion of IgM in human epithelial cancer cells. These findings indicate that human epithelial cancer cells as well as non-cancer epithelial cells can spontaneously produce IgM with natural antibody activity.

Expression of Immunoglobulin M (IgM) in Multiple Epitheliogenic Malignant Tumor Tissue and Carcinoma Cell Lines

Objective To examine the expression level of immunoglobulin M (IgM) in multiple epitheliogenic malignant tumor tissue and carcinoma cell lines. Methods Tissue microarray and immunohistochemistry were utilized to detect the expression level of IgM in ten epitheliogenic malignant tumor tissue and control negative tissue. Furthermore, flow cytometry and indirected immunofluorescence were utilized to detect the IgM expression level in eight epithelial carcinoma cell lines and the Burkitt's lymphoma cell line (Raji). Results IgM was expressed in all ten epitheliogenic malignant tumor tissue. The overall positive expression rate of IgM in tumor tissue (70.0%) was significantly higher than that of control (20.0%) (P0.05). IgM was also expressed in Raji and eight epithelial carcinoma cell lines. The positive IgM expression rate in each tumor cell line was significantly higher than that of control (P0.05). Conclusion IgM is highly expressed in multiple epitheliogenic malignant tumor tissue and carcinoma cell lines when compared to negative control. Further study is necessary to fully understand the significance and mechanisms underlying the elevated IgM levels in epitheliogenic malignant tumors.

Lower levels of surface B-cell-receptor expression in chronic lymphocytic leukemia are associated with glycosylation and folding defects of the μ and CD79a chains

AbstractLow levels of B-cell-receptor (BCR) expression are the hallmark of tumoral B lymphocytes in B-cell chronic lymphocytic leukemia (B-CLL). These cells also respond inadequately to stimulation through the BCR. This receptor consists of a surface immunoglobulin associated with a CD79a/CD79b heterodimer. We previously showed that the intracellular synthesis of BCR components, from transcription onward, is normal. Here, we investigated the glycosylation status and cellular localization of μ, CD79a, and CD79b chains in 10 CLL patients differing in surface immunoglobulin M (IgM) expression. We reported a severe impairment of the glycosylation and folding of μ and CD79a. These defects were associated with the retention of both chains in the endoplasmic reticulum and lower levels of surface IgM expression. In contrast, no clear impairment of glycosylation and folding was observed for CD79b. No sequence defects were identified for BCR components and for the chaperone proteins involved in BCR folding processes. These data show, for the first time, that lower levels of BCR surface expression observed in CLL are accounted for by an impaired glycosylation and folding of the μ and CD79a chains.

Expression of immune genes in turbot (Scophthalmus maximus) fed a nucleotide-supplemented diet

Abstract Turbot ( Scophthalmus maximus ) fed a control or nucleotide-supplemented diet for 15 weeks were examined for the relative expression of a number of immune genes. Genes analysed included those involved in specific immune responses, such as immunoglobulin M (IgM) and recombinase activating gene 1 (RAG-1), and a number of genes important for nonspecific defences (transferrin, lysozyme, cytokines). After normalising the data to the expression of a housekeeping gene (β-actin) in each sample analysed, it was found that IgM and RAG-1 gene expression were both significantly increased in the gill and spleen of fish fed the nucleotide-supplemented diet but decreased in the kidney of these fish. Transferrin expression was unaffected by the nucleotide supplementation, as was the expression of the cytokine gene transforming growth factor β. Lysozyme expression was significantly decreased in the spleen and kidney of fish fed the nucleotide-supplemented diet, with no effect apparent in the gill. In contrast, a second cytokine gene examined, interleukin-1β, showed a significant increase in expression in the kidney of the nucleotide-supplemented group. These data are discussed in relation to the differential effects seen, the function of the molecules examined and the potential for dietary modulation of fish health.