γδ T cells are abundant in the gut mucosa and play an important role in adaptive immunity as well as innate immunity. Although γδ T cells are supposed to be associated with the enhancement of Ab production, the status of γδ T cells, particularly in the synthesis of IgA isotype, remains unclear. We compared Ig expression in T cell receptor delta chain deficient (TCRδ⁻/⁻) mice with wild-type mice. The amount of IgA in fecal pellets was substantially elevated in TCRδ⁻/⁻ mice. This was paralleled by an increase in surface IgA expression and total IgA production by Peyer's patches (PPs) and mesenteric lymph node (MLN) cells. Likewise, the TCRδ⁻/⁻ mice produced much higher levels of serum IgA isotype. Here, surface IgA expression and number of IgA secreting cells were also elevated in the culture of spleen and bone marrow (BM) B cells. Germ-line α transcript, an indicator of IgA class switch recombination, higher in PP and MLN B cells from TCRδ⁻/⁻ mice, while it was not seen in inactivated B cells. Nevertheless, the frequency of IgA+ B cells was much higher in the spleen from TCRδ⁻/⁻ mice. These results suggest that γδ T cells control the early phase of B cells, in order to prevent unnecessary IgA isotype switching. Furthermore, this regulatory role of γδ T cells had lasting effects on the long-lived IgA-producing plasma cells in the BM.
Adaptive Immunity ; Animals ; B-Lymphocytes* ; Bone Marrow ; Immunity, Innate ; Immunoglobulin A* ; Immunoglobulin Class Switching* ; Lymph Nodes ; Mice ; Mucous Membrane ; Peyer's Patches ; Plasma Cells ; Receptors, Antigen, T-Cell, gamma-delta ; Recombination, Genetic ; Spleen ; T-Lymphocytes*

Dectin-1 is a major receptor that recognizes fungal cell wall β-glucan. We previously reported that heat-killed Saccharomyces cerevisiae (HKSC), a Dectin-1 agonist, selectively induces IgG1 class switching in mouse B cells. Dectin-1 is also expressed on human B cells; however, Dectin-1 function in human B cells remains unknown. This study aimed to investigate the direct effect of in vitro stimulation using HKSC on Ig class switching in human B cells. HKSC selectively induced the expression of germline γ4 transcripts (GLTγ4) by human B cell line 2E2, and HKSC significantly augmented GLTγ4 promoter activity. Moreover, HKSC selectively enhanced GLTγ4 expression and IgG4 production by anti-CD40-activated human tonsillar resting B cells. Thus, these results suggest that Dectin-1 maybe involved in selective IgG4 class switching by human B cells.
Animals ; B-Lymphocytes* ; Cell Line ; Cell Wall ; Humans* ; Immunoglobulin Class Switching ; Immunoglobulin G* ; In Vitro Techniques ; Mice ; Saccharomyces cerevisiae* ; Saccharomyces*

Interaction between pathogen-associated molecular patterns and pattern recognition receptors triggers innate and adaptive immune responses. Several studies have reported that toll-like receptors (TLRs) are involved in B cell proliferation, differentiation, and Ig class switch recombination (CSR). However, roles of TLRs in B cell activation and differentiation are not completely understood. In this study, we investigated the direct effect of stimulation of TLR1/2 agonist Pam3CSK4 on mouse B cell viability, proliferation, activation, Ig production, and Ig CSR in vitro. Treatment with 0.5 µg/ml of Pam3CSK4 only barely induced IgG1 production although it enhanced B cell viability. In addition, high-dosage Pam3CSK4 diminished IgG1 production in a dose-dependent manner, whereas the production of other Igs, cell viability, and proliferation increased. Pam3CSK4 additively increased TLR4 agonist lipopolysaccharide (LPS)-induced mouse B cell growth and activation. However, interestingly, Pam3CSK4 abrogated LPS-induced IgG1 production but enhanced LPS-induced IgG2a production. Further, Pam3CSK4 decreased LPS-induced germline γ1 transcripts (GLTγ1)/GLTε expression but increased GLTγ2a expression. On the other hand, Pam3CSK4 had no effect on LPS-induced plasma cell differentiation. Taken together, these results suggest that TLR1/2 agonist Pam3CSK4 acts as a potent mouse B cell mitogen in combination with TLR4 agonist LPS, but these 2 different TLR agonists play diverse roles in regulating the Ig CSR of each isotype, particularly IgG1/IgE and IgG2a.
Animals ; B-Lymphocytes ; Cell Proliferation ; Cell Survival ; Hand ; Immunoglobulin Class Switching ; Immunoglobulin E ; Immunoglobulin G ; In Vitro Techniques ; Mice ; Pathogen-Associated Molecular Pattern Molecules ; Plasma Cells ; Receptors, Pattern Recognition ; Recombination, Genetic ; Toll-Like Receptors

It is well established that TGF-beta1 and retinoic acid (RA) cause IgA isotype switching in mice. We recently found that lactoferrin (LF) also has an activity of IgA isotype switching in spleen B cells. The present study explored the effect of LF on the Ig production by mouse peritoneal B cells. LF, like TGF-beta1, substantially increased IgA production in peritoneal B1 cells but little in peritoneal B2 cells. In contrast, LF increased IgG2b production in peritoneal B2 cells much more strongly than in peritoneal B1 cells. LF in combination with RA further enhanced the IgA production and, interestingly, this enhancement was restricted to IgA isotype and B1 cells. Similarly, the combination of the two molecules also led to expression of gut homing molecules alpha4beta7 and CCR9 on peritoneal B1 cells, but not on peritoneal B2 cells. Thus, these results indicate that LF and RA can contribute to gut IgA response through stimulating IgA isotype switching and expression of gut-homing molecules in peritoneal B1 cells.
Animals ; B-Lymphocytes ; Immunoglobulin A* ; Immunoglobulin Class Switching ; Immunoglobulin G ; Lactoferrin* ; Mice ; Spleen ; Transforming Growth Factor beta1 ; Tretinoin*

TGF-beta induces IgA class switching by B cells. We previously reported that Smad3 and Smad4, pivotal TGF-beta signal-transducing transcription factors, mediate germline (GL) alpha transcription induced by TGF-beta1, resulting in IgA switching by mouse B cells. Post-translational sumoylation of Smad3 and Smad4 regulates TGF-beta-induced transcriptional activation in certain cell types. In the present study, we investigated the effect of sumoylation on TGF-beta1-induced, Smad3/4-mediated GLalpha transcription and IgA switching by mouse B cell line, CH12F3-2A. Overexpression of small ubiquitin-like modifier (SUMO)-1, SUMO-2 or SUMO-3 did not affect TGF-beta1-induced, Smad3/4-mediated GLalpha promoter activity, expression of endogenous GLalpha transcripts, surface IgA expression, and IgA production. Next, we tested the effect of the E3 ligase PIASy on TGF-beta1-induced, Smad3/4-mediated GLalpha promoter activity. We found that PIASy overexpression suppresses the GLalpha promoter activity in cooperation with histone deacetylase 1. Taken together, these results suggest that SUMO itself does not affect regulation of GLalpha transcription and IgA switching induced by TGF-beta1/Smad3/4, while PIASy acts as a repressor.
Animals ; B-Lymphocytes* ; Cell Line ; Histone Deacetylase 1 ; Immunoglobulin A ; Immunoglobulin Class Switching ; Mice ; Small Ubiquitin-Related Modifier Proteins* ; SUMO-1 Protein* ; Sumoylation ; Transcription Factors ; Transcriptional Activation ; Transforming Growth Factor beta ; Transforming Growth Factor beta1 ; Ubiquitin-Protein Ligases

Aluminum hydroxide (alum) is the most widely used adjuvant in human vaccines. Nevertheless, it is virtually unknown whether alum acts on B cells. In the present study, we explored the direct effect of alum on Ig expression by murine B cells in vitro. LPS-activated mouse spleen B cells were cultured with alum, and the level of isotype-specific Ig secretion, IgG1 secreting cell numbers, and Ig germ-line transcripts (GLT) were measured using ELISA, ELISPOT, and RT-PCR, respectively. Alum consistently enhanced total IgG1 production, numbers of IgG1 secreting cells, and GLTgamma1 expression. These results demonstrate that alum can directly cause IgG1 isotype switching leading to IgG1 production.
Alum Compounds ; Aluminum Hydroxide ; Animals ; B-Lymphocytes ; Cell Count ; Enzyme-Linked Immunosorbent Assay ; Enzyme-Linked Immunospot Assay ; Humans ; Hydroxides ; Immunoglobulin Class Switching ; Immunoglobulin G ; Mice ; Spleen ; Vaccines

<b>OBJECTIVEb>To study the relationship between myc gene rearrangement and myc protein expression in diffuse large B cell lymphoma (DLBCL), and their correlation with prognosis.

<b>METHODSb>One hundred and six cases of DLBCLs with follow-up data were analyzed using interphase fluorescence in situ hybridization (FISH) technique. Immunophenotyping analysis for CD20, CD3, myc, Mum-1, CD10, bcl-6 was also performed using EnVision immunohistochemistry.

<b>RESULTSb>The percentages of tumor cells expressing myc, Mum-1, CD10 and bcl-6 were 70.8%, 56.6%, 21.7% and 26.4%, respectively. Twenty six cases (24.5%) were of GCB type and the rest (75.5%) were of non-GCB (non germinal center) type. The myc rearrangement was identified in 13 (12.3%) of 106 cases. 13 cases showed to be of non-GCB type. There was no correlation between myc rearrangement and myc protein expression. DLBCLs (n = 13) with myc rearrangement showed significantly poorer overall survival (OS) and progression free survival (PFS), with a median OS and PFS time of 4.7 and 3.2 months, respectively (for OS and PFS, P < 0.001). Multivariate analysis using Cox proportional hazard model confirmed that myc rearrangement, ECOG performance status of 2-4, immunophenotyping subgroup and myc protein were independent factors affecting the prognosis and significantly associated with the survival. However, myc rearrangement was the strongest prognostic factor.

<b>CONCLUSIONSb>DLBCL with myc gene rearrangement is a subgroup of non-GCB DLBCL with poor outcome. It is an independent and useful factor for prognosis in DLBCL. Expression of myc is influenced by many factors and myc rearrangement may be one of these factors.

Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Cyclophosphamide ; therapeutic use ; Disease-Free Survival ; Doxorubicin ; therapeutic use ; Female ; Follow-Up Studies ; Gene Rearrangement, B-Lymphocyte ; Genes, myc ; Humans ; In Situ Hybridization, Fluorescence ; Interferon Regulatory Factors ; metabolism ; Lymphoma, Large B-Cell, Diffuse ; drug therapy ; genetics ; metabolism ; pathology ; Male ; Middle Aged ; Neoplasm Staging ; Neprilysin ; metabolism ; Prednisone ; therapeutic use ; Proportional Hazards Models ; Proto-Oncogene Proteins c-bcl-6 ; metabolism ; Proto-Oncogene Proteins c-myc ; metabolism ; Survival Rate ; Vincristine ; therapeutic use

Antigens, Differentiation, B-Lymphocyte ; genetics ; Carcinoma, Non-Small-Cell Lung ; drug therapy ; genetics ; metabolism ; Gene Fusion ; Gene Rearrangement ; Histocompatibility Antigens Class II ; genetics ; Humans ; Immunohistochemistry ; In Situ Hybridization, Fluorescence ; Lung Neoplasms ; drug therapy ; genetics ; metabolism ; Protein Kinase Inhibitors ; therapeutic use ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; genetics ; metabolism ; Proto-Oncogene Proteins ; antagonists & inhibitors ; genetics ; metabolism ; Pyrazoles ; therapeutic use ; Pyridines ; therapeutic use ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; Sodium-Phosphate Cotransporter Proteins, Type IIb ; genetics

<b>OBJECTIVEb>To study the clinicopathologic features and differential diagnosis of splenic B-cell marginal zone lymphoma (SMZL) involving bone marrow.

<b>METHODSb>The clinical and pathologic features of 22 patients with SMZL were retrospectively studied. Immunophenotypic analysis was carried out by flow cytometry and immunohistochemistry. Immunoglobulin heavy chain rearrangement study was performed using polymerase chain reaction-based method.

<b>RESULTSb>Villous lymphocytes were found in peripheral blood smears of 11/18 of the patients. In bone marrow aspirates, lymphocytosis (> 20%) was demonstrated in 15 cases (15/18) and villous lymphocytes in 6 cases (6/18). Flow cytometry showed CD19(+) CD20(+) FMC7(+) CD22(+) CD10(-) CD2(-) CD3(-) CD7(-) in 18 cases. Bone marrow biopsies of all the 22 patients revealed various degrees and patterns of neoplastic infiltration, as follows: mild (4 cases, 18.2%), moderate (11 cases, 50.0%) or severe (7 cases, 31.8%); intrasinusoidal (16 cases, 72.7%), interstitial (14 cases, 63.6%), nodular (11 cases, 50.0%) or diffuse (1 case, 4.5%). Reactive germinal center formation (CD23(+) bcl-2(-)) was found in 2 cases (91.0%). Immunohistochemical study showed the following results: CD20(+) PAX5(+) CD3(-) CD5(-) CD10(-) cyclin D1(-) CD23(-) CD43(-) Annexin A1(-) CD11C(-) CD25(-) in all the 22 cases, CD38(+) in 2 cases (9.1%) and CD138(+) in 2 cases (9.1%).

<b>CONCLUSIONSb>Different and overlapping patterns of bone marrow involvement are observed in SMZL. As the histologic and immunophenotypic features are not specific to SMZL, distinction from other types of mature B-cell lymphomas is necessary.

Adult ; Aged ; Aged, 80 and over ; Antigens, CD20 ; metabolism ; Bone Marrow ; pathology ; Diagnosis, Differential ; Female ; Gene Rearrangement, B-Lymphocyte, Heavy Chain ; Humans ; Leukemia, Lymphocytic, Chronic, B-Cell ; metabolism ; pathology ; Lymphoma, B-Cell, Marginal Zone ; genetics ; metabolism ; pathology ; Lymphoma, Follicular ; metabolism ; pathology ; Lymphoma, Mantle-Cell ; metabolism ; pathology ; Male ; Middle Aged ; Neoplasm Invasiveness ; Retrospective Studies ; Splenic Neoplasms ; genetics ; metabolism ; pathology ; Waldenstrom Macroglobulinemia ; metabolism ; pathology

<b>OBJECTIVEb>To study the clinicopathologic features, immunohistochemical findings, differential diagnosis and prognosis of type II enteropathy-associated T-cell lymphoma (EATL).

<b>METHODSb>Fourteen cases of type II EATL encountered in Department of Pathology, Nanjing General Hospital were retrospectively reviewed. The clinical data, histologic features, immunohistochemical findings and follow-up information were analyzed, with literature review.

<b>RESULTSb>There were altogether 12 males and 2 females. The median age of patient was 49 years. The sites of involvement included jejunum (10 cases) and ileum/colon (4 cases). The patients often presented with an abdominal mass, abdominal pain, diarrhea and constitutional symptoms such as fever, night sweating and cachexia. There was no clinical evidence of gluten-sensitive enteropathy. Histologically, the lymphoma cells showed full-thickness infiltration of the intestinal wall. They contained round hyperchromatic nuclei and pale cytoplasm. The stroma was minimally inflamed, with or without associated coagulative necrosis. A remarkable finding was the presence of villous atrophy, cryptal hyperplasia and intraepithelial lymphocytosis. Immunohistochemical study showed that the tumor cells expressed CD3, CD43 and CD8 (14/14). Some of them were also positive for CD56 (11/14) and CD30 (2/14). The staining for CD4, CD20, CD79a and myeloperoxidase was negative. A high proliferation index was demonstrated by Ki-67 immunostain. In-situ hybridization for EBER was negative. Follow-up data were available in 9 cases. The duration of follow-up ranged from 6 months to 36 months. Seven patients died within 14 months.

<b>CONCLUSIONSb>EATL is a rare type of lymphoma with intestinal involvement. Associated enteropathy is not demonstrated, in contrast to cases encountered in Nordic countries. A correct diagnosis requires evaluation of clinical manifestations, pathologic features and ancillary study results.

Adolescent ; Adult ; Aged ; CD3 Complex ; metabolism ; CD8 Antigens ; metabolism ; Diagnosis, Differential ; Enteropathy-Associated T-Cell Lymphoma ; genetics ; immunology ; pathology ; surgery ; Female ; Follow-Up Studies ; Gene Rearrangement, T-Lymphocyte ; Humans ; Ileal Neoplasms ; genetics ; immunology ; pathology ; surgery ; Jejunal Neoplasms ; genetics ; immunology ; pathology ; surgery ; Leukosialin ; metabolism ; Lymphoma, B-Cell, Marginal Zone ; metabolism ; pathology ; Lymphoma, Extranodal NK-T-Cell ; metabolism ; pathology ; Lymphoma, Large B-Cell, Diffuse ; metabolism ; pathology ; Male ; Middle Aged ; Retrospective Studies ; Young Adult