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Summary: Immunological memory protects the human body from re-infection with an earlier recognized pathogen. This memory comprises the durable serum antibody titres provided by long-lived plasma cells and the memory T and B cells with help from other cells. Memory B cells are the main precursor cells for new plasma cells during a secondary infection. Their formation starts very early in life, and they continue to form and undergo refinements throughout our lifetime. While the heterogeneity of the human memory B-cell pool is still poorly understood, specific cellular surface markers define most of the cell subpopulations. CD27 is one of the most commonly used markers to define human memory B cells. In addition, there are molecular markers, such as somatic mutations in the immunoglobulin heavy and light chains and isotype switching to, for example, IgG. Although not every memory B cell undergoes somatic hypermutation or isotype switching, most of them express these molecular traits in adulthood. In this review, I will focus on the most recent knowledge regarding CD27+ human memory B cells in health and disease, and describe how Ig sequencing can be used as a tool to decipher the evolutionary pathways of these cells. Memory B cells are essential for our immunological memory and respond rapidly to reinfection. CD27 is a widely used cell surface marker for human memory B cells and is gradually upregulated during the germinal centre reaction. Here, an overview of recent data on human CD27+ memory B cells is presented with emphasis on function and immunoglobulin sequencing. [ABSTRACT FROM AUTHOR]

Objective. To characterize the expression of malondialdehdye-acetaldehyde (MAA) adducts and anti- MAA antibody in articular tissues and serum of patients with RA. Methods. Paired sera and SF were examined from 29 RA and 13 OA patients. Anti-MAA antibody, RF, ACPA and total immunoglobulin were quantified. SF-serum measures were compared within and between disease groups. The presence and co-localization of MAA, citrulline and select leukocyte antigens in RA and OA synovial tissues were examined using immunohistochemistry. Results. Circulating and SF anti-MAA antibody concentrations were higher in RA vs OA by 1.5- to 5-fold. IgG (P < 0.001), IgM (P = 0.006) and IgA (P = 0.036) anti-MAA antibodies were higher in paired RA SF than serum, differences not observed for total immunoglobulin, RF or ACPA. In RA synovial tissues, co-localization of MAA with citrulline and CD19+ or CD27+ B cells was demonstrated and was much higher in magnitude than MAA or citrulline co-localization with T cells, monocytes, macrophages or dendritic cells (P < 0.01). Conclusion. Anti-MAA antibodies are present in higher concentrations in the RA joint compared with sera, a finding not observed for other disease-related autoantibodies. Co-localization of MAA and citrulline with mature B cells, coupled with the local enrichment of anti-MAA immune responses, implicates MAA-adduct formation in local autoantibody production. [ABSTRACT FROM AUTHOR]

Depression and pain are two of the most debilitating disorders worldwide and have an estimated cooccurrence of up to 80%. Comorbidity of these disorders is more difficult to treat, associated with significant disability and impaired healthrelated quality of life than either condition alone, resulting in enormous social and economic cost. Several neural substrates have been identified as potential mediators in the association between depression and pain, including neuroanatomical reorganization, monoamine and neurotrophin depletion, dysregulation of the hypothalamo-pituitary-adrenal axis, and neuroinflammation. However, the past decade has seen mounting evidence supporting a role for the endogenous cannabinoid (endocannabinoid) system in affective and nociceptive processing, and thus, alterations in this system may play a key role in reciprocal interactions between depression and pain. This review will provide an overview of the preclinical evidence supporting an interaction between depression and pain and the evidence supporting a role for the endocannabinoid system in this interaction. [ABSTRACT FROM AUTHOR]

We summarize knowledge and open questions on how plants achieve morphological symmetries and asymmetries by controlling cell division, and known links between the cell cycle and organ shape, particularly the leaf.The body architectures of most multicellular organisms consistently display both symmetry and asymmetry. Here, we discuss some of the available knowledge and open questions on how symmetry and asymmetry appear in several conspicuous plant cells and tissues. We focus, where possible, on the role of genes that participate in the maintenance or the breaking of symmetry and that are directly or indirectly related to the cell cycle, under an organ-centric point of view and with an emphasis on the leaf. [ABSTRACT FROM PUBLISHER]

Prosthesis-patient mismatch (PPM) is defined as a too-small effective orifice area (EOA) of an inserted prosthetic relative to body size, resulting in an abnormally high postoperative gradient. It is unclear, however, whether residual stenosis after aortic valve replacement (AVR) has a negative impact on mid- and long-term survivals. We searched electronic databases, including PubMed, Embase, Medline and the Cochrane controlled trials register, through October 2012, to identify published full-text English studies on the association between PPM and mortality rates. A significant PPM was defined as an indexed EOA (iEOA) <0.85 cm2/m2, and severe PPM as an iEOA <0.65 cm2/m2. Two reviewers independently assessed the studies for inclusion and extracted data. Fourteen observational studies, involving 14 874 patients, met our final inclusion criteria. Meta-analysis demonstrated that PPM significantly increased mid-term (odds ratio [OR] 1.42, 95% confidence interval [CI] 1.19–1.69) and long-term (OR 1.52, 95% CI 1.26–1.84) all-cause mortalities. Subgroup analysis showed that PPM was associated with higher mid- and long-term mortality rates only in younger and predominantly female populations. Risk-adjusted sensitivity analysis showed that severe PPM was associated with reduced survival (adjusted hazard ratio [HR] 1.50, 95% CI 1.24–1.80), whereas moderate PPM was not (adjusted HR 0.96, 95% CI 0.86–1.07). Regardless of severity, however, PPM had a negative effect on survival in patients with impaired ejection fraction (adjusted HR 1.26, 95% CI 1.09–1.47). PPM (iEOA <0.85 cm2/m2) after AVR tended to be associated with increased long-term all-cause mortality in younger patients, females and patients with preoperative left ventricular dysfunction. Severe PPM (iEOA <0.65 cm2/m2) was a significant predictor of reduced long-term survival in all populations undergoing AVR. [ABSTRACT FROM PUBLISHER]

Aims Numerous studies have linked prosthesis–patient mismatch (PPM) after aortic valve replacement (AVR) to adverse outcomes. Its correlation with long-term survival has been described but with contradicting results. This systematic review and meta-analysis of observational studies aims to determine the hazard of PPM after AVR. Methods and results The Medline and EMBase databases were searched for English-language original publications. Two researchers independently screened studies and extracted data. Pooled estimates were obtained by random effects model. Subgroup analyses were performed to detect sources of heterogeneity. The search yielded 348 potentially relevant studies; 34 were included comprising 27 186 patients and 133 141 patient-years. Defined by the universally accredited indexed effective orifice area <0.85 cm2/m2, 44.2% of patients were categorized as having PPM. In 34.2 and 9.8% of patients moderate (0.65–0.85 cm2/m2) and severe (<0.65 cm2/m2) PPM was present, respectively. Prosthesis–patient mismatch was associated with a statistically significant increase in all-cause mortality (HR = 1.34, 95% CI: 1.18–1.51), but only a trend to an increase in cardiac-related mortality (HR = 1.51, 95% CI: 0.88–2.60) was recognized. Analysis by severity of PPM demonstrated that both moderate and severe PPM increased all-cause mortality (HR = 1.19, 95% CI: 1.07–1.33 and HR = 1.84, 95% CI: 1.38–2.45) and cardiac-related mortality (HR = 1.32, 95% CI: 1.02–1.71 and HR = 6.46, 95% CI: 2.79–14.97). Further analyses showed a consistent effect over separate time intervals during follow-up. Conclusion Prosthesis–patient mismatch is associated with an increase in all-cause and cardiac-related mortality over long-term follow-up. We recommend that current efforts to prevent PPM should receive more emphasis and a widespread acceptance to improve long-term survival after AVR. [ABSTRACT FROM PUBLISHER]

Background: Classical anatomical descriptions fail to describe variants often observed in the axilla as they are based on studies that looked at individual structures in isolation or textbooks of cadaveric dissections. The presence of variant anatomy heightens the risk of iatrogenic injury. The aim of this study was to document the nature and frequency of these anatomical variations based on in vivo peroperative surgical observations. Methods: Detailed anatomical relationships were documented prospectively during consecutive axillary dissections. Relationships between the thoracodorsal pedicle, course of the lateral thoracic vein, presence of latissimus dorsi muscle slips, variations in axillary and angular vein anatomy, and origins and branching of the intercostobrachial nerve were recorded. Results: Among a total of 73 axillary dissections, 43 (59 per cent) revealed at least one anatomical variant. Most notable variants included aberrant courses of the thoracodorsal nerve in ten patients (14 per cent)-three variants; lateral thoracic vein in 12 patients (16 per cent)-four variants; bifid axillary veins in ten patients (14 per cent); latissimus dorsi muscle slips in four patients (5 per cent); and variants in intercostobrachial nerve origins and branching in 26 patients (36 per cent). The angular vein, a subscapular vein tributary, was found to be a constant axillary structure. Conclusion: Variations in axillary anatomical structures are common. Poor understanding of these variants can affect the adequacy of oncological clearance, lead to vascular injury, compromise planned microvascular procedures and result in chronic pain or numbness from nerve injury. Surgeons should be aware of the common anatomical variants to facilitate efficient and safe axillary surgery. Copyright © 2012 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Background. Impaired methylation of T-cell DNA is thought to contribute to the development of systemic lupus erythematosus (SLE). CD70 ( TNFSF7) is a B-cell costimulatory molecule that contributes to excessive B-cell stimulation in vitro and in vivo. CD70 is overexpressed in CD4+ T cells of patients with SLE, and DNA demethylation occurs in promoter sequences that regulate CD70 expression in SLE CD4+ T cells. However, it is unknown whether the expression and methylation of CD70 in CD4 + T cells are affected in patients with subacute cutaneous lupus erythematosus (SCLE). Objective. To compare CD70 expression levels and the methylation status of the CD70 promoter region in CD4+ T cells from patients with SCLE and healthy controls. Methods. We used real-time RT-PCR to compare messenger RNA levels of CD70 and flow cytometry to compare CD70 protein levels in CD4 + T cells from patients with SCLE and healthy controls. Bisulphite sequencing was used to determine the methylation status of the CD70 promoter region. Results. CD70 is overexpressed at the surface of SCLE CD4 + T cells. Demethylation of the CD70 promoter region was seen in CD4 + T cells from patients with SCLE. Conclusions. Demethylation of regulatory elements contributes to CD70 overexpression in CD4 + T cells of patients with SCLE. [ABSTRACT FROM AUTHOR]

Objective. To characterize circulating B-cell subpopulations of arthritis patients with <6 weeks of disease duration. [ABSTRACT FROM PUBLISHER]

Understanding primary immunodeficiencies has elucidated many aspects of human immunity and susceptibility to infections. Recently, defects have been identified that result in deficiencies of terminally differentiated subsets of lymphocytes including deficiencies of memory B cells, NKT cells and Th17 T cells. Together with defects specific to Th1 responses, these disorders revealed that dedicated pathogen-specific mechanisms exist for prevalent human pathogens, and that some host defence strategies are remarkably specific. Deficiency of Th17 cells confirms that this subset of effector T cells is important for defence at epithelial surfaces. The clinical phenotype includes devastating complications from infection with Staphylococcus aureus. Since the microbial load at human epithelial surfaces is substantial and enormously diverse, this specificity could hold clues that are important for understanding first the complex symbiosis with mucosal commensals and second for understanding the consequences of manipulating these populations in inflammatory diseases. [ABSTRACT FROM PUBLISHER]

The interaction of chemokines and their receptors directs lymphocyte migration, and is involved in the distribution and organization of lymphocytes within lymphoid tissues. We reasoned that abnormal chemokine receptor expression might give rise to defects of lymphocyte migration into and within lymphoid tissues, and consequently be associated with defective antibody production in primary antibody deficiencies. In this study, we have investigated the expression of chemokine receptors CXCR4, CXCR5 and CCR7 on lymphocyte subpopulations (naive and memory B cells; CD4+ and CD8+ T cells) in a cohort of patients with primary antibody deficiency ( n = 23), and compared these with a group of healthy controls ( n = 19). We show that there were significant differences in both the proportions of lymphocytes expressing, and the levels of expression of, specific chemokine receptors on individual lymphocyte subpopulations between patients and controls. Furthermore, these changes appeared more pronounced in patients with more severe antibody deficiency. These data support the hypothesis that abnormal lymphocyte trafficking may be involved in the pathogenesis of primary antibody deficiencies. [ABSTRACT FROM AUTHOR]

Newborn babies possess a functional but immature immune system as a defense against a world teeming with microorganisms. Breast milk contains a number of biological, active compounds that support the infant's immune system. These include secretory immunoglobulin A (IgA), which confers specific protection against enteric pathogens, as well as numerous other immunological, active ingredients. A number of these ingredients can be used as supplements for infant formulas based on cow's milk. Here, the strength of evidence regarding the immune-stimulating effects of selected minerals, vitamins, fatty acids, pre- and probiotics, and nucleotides is reviewed. An assessment of how these ingredients are used in infant-formula products currently available on the market is also presented. [ABSTRACT FROM AUTHOR]

To investigate age-related alterations in human humoral immunity, we analyzed the quantity and quality of peripheral B cell subsets, CD27-negative (CD27-) and CD27-positive (CD27+) B cells, by flow cytometry analysis in 54 aged individuals (mean age SE, 74.6 0.7 years) and 30 young individuals (mean age SE, 26.1 0.5 years). CD27- and CD27+ B cells are regarded as naive and memory B cells, respectively. CD38, Ki-67, CD95 and bcl-2 were used as activation, proliferation and apoptotic markers. Susceptibility to apoptosis was evaluated by cell size and annexin-V binding in culture cells. The percentage of CD27+ B cells was significantly lower in aged (mean, 19.2%) individuals than that in young individuals (mean, 28.2%). The opposite was true for CD27- B cells (mean, 80.8% in aged and 71.8% in young) (P < 0.01). The absolute number of CD27+ B cells in aged individuals was significantly less than the number of CD27- B cells. The CD27+ B cells from aged individuals showed little susceptibility to apoptosis, although CD95 expression on the CD27+ B cells was significantly higher in the aged individuals than in the young individuals (P < 0.05). The CD38 and bcl-2 expression on the CD27- B cells was significantly higher in the aged individuals than in the young individuals (P < 0.05). In addition, the CD27- B cells from the aged individuals showed a decreased susceptibility to apoptosis compared with that of the young individuals. These findings suggested that human aging leads to both quantitative and qualitative alterations in the peripheral B cell developmental system, including memory and naive B cell balance and their surface phenotypes. [ABSTRACT FROM AUTHOR]

Wiskott–Aldrich syndrome (WAS) is an X-linked immunodeficiency/platelet disease due to mutations of WASP, a cytoskeletal regulatory protein of blood cells. Patients exhibit a range of immune defects generally attributed to defective T-cell function, including poor response to immunization, skewed immunoglobulin isotypes, eczema, recurrent infections, autoimmune disease and increased frequency of malignancies. Here we show a deficit of total B-cells in WAS patients of various ages and identify phenotypic perturbations involving complement receptors and CD27. Whereas B-cells of normal healthy donors are overwhelmingly CD21/CD35-positive, B-cells expressing these receptors are significantly reduced in number in WAS patients, and their paucity may cause suboptimal antigen capture and presentation. The frequencies of IgD– and IgG+ patient B-cells were not different from healthy donors (although absolute numbers were decreased), indicating that isotype switching is occurring. In contrast, the frequency of cells positive for CD27, the marker of post germinal centre B-cells, was significantly decreased even among isotype-switched cells, and B-cells resembling germinal centre progenitors (CD10+CD27–CD38bright) were more frequent in adult patients, suggesting impaired germinal centre maturation/differentiation. The documentation of these phenotypic perturbations and deficit of total cells suggest that defects intrinsic to B-cells contribute to the impaired humoral immunity that characterizes this disease. [ABSTRACT FROM AUTHOR]

Reduced serum IgG and subclass levels have been demonstrated in children with chronic renal failure. To study possible causes of this reduction, we analysed B cell subset composition, T helper cell frequencies and immunoglobulin (Ig) production capacity in vitro in children with chronic renal failure, with or without dialysis treatment. B cell subsets were characterized by determining CD27, IgM, IgD and CD5 expression within the CD19+ population. Intracellular expression of interferon (IFN)- γ, interleukin (IL)-2 and IL-4 in PMA/ionomycin-stimulated peripheral blood mononuclear cells (PBMC) was used to evaluate T helper frequencies. The capacity of B cells to secrete Ig in vitro was determined by measuring IgG1, IgG2 and IgM in culture supernatants of anti-CD2/CD28 monoclonal antibody (MoAb)- or SAC/IL-2-stimulated PBMC. Memory B cell numbers (identified as percentage or absolute number of CD19+ IgM¯IgD¯ or CD19+CD27+ lymphocytes) were lower in children treated with haemodialysis (HD), peritoneal dialysis (PD) and children with chronic renal failure before starting dialysis treatment (CRF) compared to healthy controls (HC) ( P < 0·05). Compared with HC, CD5+ (naive) B cells were reduced in HD-treated patients but not for PD or for children with chronic renal failure before starting dialysis treatment (CRF). No significant differences in CD4+ T helper cell subsets were found between the groups. However, CRF children had a higher percentage of IFN- γ producing CD8+ T lymphocytes compared to HC ( P = 0·02). Finally, IgG1, IgG2 and IgM production in vitro was similar in the four groups. In conclusion, significantly lower numbers of memory type B cells were found in children with chronic renal failure compared to healthy controls. This reduction may contribute to the low Ig levels found in these children. [ABSTRACT FROM AUTHOR]

Human neonates are immunologically immature and consequently are highly susceptible to infection. The cellular basis for the dysfunctional immune responses of neonates is not clear, but is likely to reflect the immaturity of both B and T cell populations. Here we have examined the ability of human cord blood B cells to respond to antigen receptor cross-linking and also to CpG containing oligodeoxynucleotides (ODN), and compared their responses with those of adult peripheral blood B cells. Antigen receptor cross-linking with soluble F(ab′)2 anti-IgM antibodies, induced HLA-DR and CD86 up-regulation and proliferation to a similar extent in adult and cord blood B cells. Both interleukin (IL)-2 and IL-4 co-stimulated anti-IgM-induced proliferation, but cord blood B cells were less sensitive than adult B cells to the co-stimulatory effects of IL-2. Antigen receptor cross-linking induced secretion of the chemokines macrophage inflammatory protein-1 α (MIP-1 α) and MIP-1 β in adult and cord blood B cells, and secretion was enhanced by IL-2 or IL-4. CpG-ODN induced up-regulation of HLA-DR and CD86 expression and proliferation of adult and cord blood B cells, and anti-IgM and CPG-ODN synergized in the induction of proliferation. CpG-ODN also induced MIP-1 α and MIP-1 α secretion in adult and cord blood B cells. In addition to functional studies we examined the expression of CD62L ( l-selectin), CCR7 and CXCR5. Our data show that surface expression of CD62L and CCR7 is lower on cord blood B cells than on adult B cells, suggesting that human cord blood B cells may exhibit homing defects. [ABSTRACT FROM AUTHOR]

Neonatal CD4+ T cells express less CD154 protein and mRNA than adult CD4+ T cells after activation by calcium ionophore and phorbol ester, but the mechanism for this reduced expression and its relevance to the primary immune response remain unclear. We compared expression of CD154 protein and mRNA and CD154 gene promoter activity by purified naive (CD45RAhighCD45ROlow) neonatal and adult CD4+ T cells after activation by calcium ionophore (ionomycin) and phorbol myristate acetate (PMA) treatment or by engagement of αβ TCR-CD3 complex. Substantial and consistent reductions in expression by neonatal cells were found in all cases and were paralleled by decreased CD154-dependent activation of a B cell line. CD69 expression by neonatal CD4+ T cells after αβ TCR-CD3 engagement was also reduced compared to adult cells, which suggested that limitations in activation-induced signaling by neonatal CD4+ T cells occurred at a point upstream of where the signaling pathways leading to CD154 and CD69 expression diverge. Decreased CD154 expression by neonatal cells after αβ TCR-CD3 engagement was paralleled by a lower free intracellular calcium concentration, a key event for CD154 gene transcription. Reduced CD154 promoter activity by neonatal cells persisted when proximal signaling events were bypassed using ionomycin and PMA, suggesting an additional and more distal mechanism for decreased transcription. In contrast, CD154 mRNA stability was similar in neonatal and adult cells after either ionomycin and PMA stimulation or engagement of the αβ TCR-CD3 complex. We conclude that decreased CD154 production by neonatal CD4+ T cells is due to limitations in both proximal and distal activation events, which together ultimately limit CD154 gene transcription. [ABSTRACT FROM AUTHOR]

SUMMARY The objective of this study was to investigate if oligoclonality of the Ig repertoire post-haematopoietic stem cell transplantation (HSCT) is restricted to memory B lymphocytes or if it is a general property among B lymphocytes. As a measure of B lymphocyte repertoire diversity, we have analysed size distribution of polymerase chain reaction (PCR) amplified Ig H complementarity determining region 3 (CDR3) in naive and memory B lymphocytes isolated from patients before HSCT and at 3, 6 and 12 months after HSCT as well as from healthy controls. We demonstrate a limited variation of the IgH CDR3 repertoire in the memory B lymphocyte population compared to the naive B cell population. This difference was significant at 3 and 6 months post-HSCT. Compared to healthy controls there is a significant restriction of the memory B lymphocyte repertoire at 3 months after HSCT, but not of the naive B lymphocyte repertoire. Twelve months after HSCT, the IgH CDR3 repertoire in both memory and naive B lymphocytes are as diverse as in healthy controls. Thus, our findings suggest a role for memory B cells in the restriction of the oligoclonal B cell repertoire observed early after HSCT, which may be of importance when considering reimmunization of transplanted patients. [ABSTRACT FROM AUTHOR]

Previous studies of age-associated immune system changes revealed alterations in expressed immunoglobulin heavy chain variable domain repertoires, and variability in the fraction of expressed heavy chain variable domain genes with mutations. To test whether the latter finding reflected a variation in memory B-cell numbers, we measured circulating memory B cells of 11 healthy elderly subjects, 173 nursing-home residents, and 34 healthy young adults. A large fraction of old adults have low values for memory cells both as a percentage of all B cells and as an absolute memory B-cell concentration. The range of both values is much wider in old adults than in young adults, and it is much wider than the range of T-cell concentrations. Memory B-cell concentration, which was positively correlated with memory T-cell concentrations but inversely related to in vitro T-cell responses to mitogens, may reflect highly individual rates of immune senescence, and it may serve as an amplified marker of underlying T-cell function. [ABSTRACT FROM AUTHOR]

SUMMARY CVID is characterized by reduced serum levels of all switched immunoglobulin isotypes (IgG, IgA, IgE) predisposing patients to recurrent infections of their respiratory and gastrointestinal tract. Correspondingly, most CVID patients exhibit a severely decreased proportion of class switched memory B cells (CD19+ CD27+ IgD- IgM- IgG+ or IgA+ ) in their peripheral blood (CVID type I). We previously identified a subgroup of CVID patients showing a significantly reduced expression of CD86 and CD137 following activation in vitro of PBMC or purified B cells (CD19+ ) with anti-IgM plus IL-2. Here we extend our previous studies by asking whether highly purified, cell-sorted naive B cells show already an expression defect of B cell surface molecules relevant in activation (CD39, CD69), differentiation (CD24, CD27, CD38) or T–B interaction (CD25, CD70, CD86). We stimulated cell-sorted, naive B cells (CD19+ CD27- IgM+ IgDhigh IgG- IgA- ) from 10 CVID patients and 10 healthy controls for 4 days with anti-IgM plus IL-2 in the absence or presence of autologous CD4+ T cells and measured the expression of the referred surface molecules. Based on reduced or normal numbers of switched memory B cells the CVID patients had previously been classified into eight type I patients and two type II patients, respectively. Interestingly, only the molecules CD25, CD70 and CD86, all relevant in cognate T–B interaction, showed a significantly lower expression in naive B cells from CVID patients compared to controls. While coculture with autologous CD4+ T cells normalized the CD25 expression, CD70 and CD86 expression remained subnormal, notably in the eight CVID patients of type I. These findings strongly suggest an intrinsic signalling or expression defect for CD70/CD86 at the level of naive B cells in type I... [ABSTRACT FROM AUTHOR]

CD27 and CD134 ligand (CD134L) are two B cell co-receptors for Th cell activation-induced ligands (i.e. CD70 and CD134) that promote differentiation of B cells into plasma cells and high-rate antibody production respectively. We explored the CD27 pathway and T cell CD134 expression in common variable immunodeficiency (CVID), a disease characterized by a lack of plasma cells and low Ig serum levels. Twelve patients were compared to seven healthy controls. We found a low percentage of circulating CD27+ B cells in seven patients and B cell CD27 expression was not up-regulated by in vitro activation in two of them. Importantly, the number of circulating CD27+ B cells was correlated with the severity of the disease—the patients with the lowest CD27+ B cell counts having the lowest serum Ig concentrations and the lowest total peripheral blood B cell counts. In contrast, CD70 and CD134 were normally expressed on in vitro activated T cells. CD134L was not detected on patient and control B cells in our activation conditions. Functional studies of in vitro Ig production demonstrated an absence of B cell response to CD27 cross-linking, in particular in a patient with normal CD27 expression. Our results indicate that a defect in CD27 expression or function contributes to the pathogenesis of certain severe forms of CVID. [ABSTRACT FROM PUBLISHER]

The principal roles of B/B-cell interactions in immune response have not yet been established. We therefore investigated B/B-cell interactions in immunoglobulin synthesis via direct cell-to-cell contact, particularly in the tumour necrosis factor receptor (TNFR)/tumour necrosis factor (TNF) family. We prepared highly purified peripheral blood B cells and stimulated them with Epstein–Barr virus (EBV)-transformed B lymphoblastoid cell lines (LCLs) as activated human B cells. The IgG production by B cells was increased by the addition of fixed LCLs in a dose-dependent manner in the presence of IL-10 plus IL-2. LCLs strongly expressed CD40 and CD70 on their surface, but marginal or no CD154, CD27, OX40 (CD134) and CD134 ligand. The enhancement of immunoglobulin production by LCLs was completely blocked by the initial addition of anti-CD70 blocking MoAb, but not by anti-CD154 or anti-CD134 ligand MoAb. The addition of LCLs also caused a reduction in CD27 expression on B cells, and this effect was completely blocked by anti-CD70 MoAb, indicating a direct B cell–LCL contact via CD27/CD70. LCLs markedly promoted B-cell differentiation into plasma cells in the presence of IL-10 plus IL-2. These findings demonstrate that direct interactions between B and B cells via CD27/CD70 induce immunoglobulin production by promoting the generation of plasma cells. [ABSTRACT FROM AUTHOR]

The B-cell lineage in a patient with B-cell-negative severe combined immunodeficiency (SCID) was analysed by using antisurrogate light chain (SL) MoAbs. Peripheral CD3+ T cells and CD19+ B cells were absent in the patient. The common gamma (γc) chain was expressed normally on the patient's peripheral NK cells and his peripheral mononuclear cells did not possess any mutations in recombinase activating gene (RAG)-1, 2. Normal levels of expression of Ku70 and Ku80 protein were found by Western blot analysis. The patient did, however, display an increase in fibroblast sensitivity to irradiation. Furthermore, flow cytometric analyses of bone marrow cells showed that surface IgM and cytoplasmic µ positive cells were absent and that CD19+ B cells were composed of only CD34+ terminal deoxynucleotidyl transferase (TdT)+ SL+ pro-B cells. The complete arrest of pro- to pre-B cell development in the SCID patient's bone marrow suggests that some genes involved in V(D)J recombination, excepting the RAG gene, may play a causative role in the immunodeficiency. [ABSTRACT FROM AUTHOR]

Analysis of the VHDJH repertoire of peripheral blood IgM+ B cells from a patient with X-linked hyper-IgM syndrome (X-HIgM) was undertaken to determine whether the distribution of VH families in the productive repertoire might be regulated by in vivo CD40–CD154 interactions. The distribution of VH genes in the non-productive repertoire of IgM+ B cells was comparable in X-HIgM and normals. Unlike the normal productive VH repertoire, however, in the X-HIgM patient the VH4 family was found at almost the same frequency as the VH3 family. This reflected a diminution in the positive selection of the VH3 family observed in normals and the imposition of positive selection of the VH4 family in the X-HIgM patient. Unique among the VH3 genes, VH3-23/DP-47 was positively selected in both normals and the X-HIgM patient. No major differences in the usage of JH or D segments or the complementarity-determining region (CDR) 3 were noted, although the foreshortening of the CDR3 noted in the mutated VH rearrangements of normals was absent in the X-HIgM patient. Finally, a minor degree of somatic hypermutation was noted in the X-HIgM patient. These results have suggested that specific influences on the composition of the VH repertoire in normals require CD40–CD154 interactions. [ABSTRACT FROM PUBLISHER]

The activated macrophages present in the 1' cell-dependent granulomata of sarcoidosis and tuberculosis are primed or enhanced release of cytokines including tumour necrosis factor (TN F or cachectin). Release of this cytokine can induce an acute-phase response. fever, and necrosis in suitably prepared sites of inflammation: if chronic. its presence may contribute to weight loss. These clinical features are characteristic of tuberculosis, hut not of sarcoidosis, though alveolar macrophages from both diseases release large quantities of TN F in vitro. We therefore postulated the presence in sarcoidosis patients alan inhibitor of TNF. We have studied levels of INF inhibitory activity by determining the quantity of TNF, required to give 50% kill of 1.929 cells in the presence of 20% heat-inactivated serum derived from various disease states (37 sarcoidosis. 13 tuberculosis. 13 Crohn's disease, 17 healthy donors). Normal sent used in ibis way do not inhibit significantly, but inhibition of TNF toxicity is caused by most sent from both sarcoidosis and tuberculosis. Used at 20%, five out of 37 sarcoidosis sera and one out in 13 tuberculosis sera caused complete inhibition of TNF. even when the latter was added at 1(R) times the concentration required to give 50'% kill in control wells. This inhibitor tiny have an important physiological role. [ABSTRACT FROM AUTHOR]

Chronic inhalation of coal dust can cause several lung disorders, including simple coalworkers pneumoconiosis (CWP), progressive massive fibrosis (PMF), chronic bronchitis, lungfunction loss, and emphysema. This review focuses on the cellular actions and interactions ofkey inflammatory cells and target cells in coal dust toxicity and related lung disorders, i.e.macrophages and neutrophils, epithelial cells, and fibroblasts. Factors released from or affectingthese cells are outlined in separate sections, i.e. (1) reactive oxygen species (ROS) and relatedantioxidant protection mechanisms, and (2) cytokines, growth factors and related proteins.Furthermore, (3) components of the extracellular matrix (ECM), including the modifying role ofROS, cytokines, proteases and antiproteases are discussed in relation to tissue damage andremodelling in the respiratory tract. [ABSTRACT FROM PUBLISHER]

CD27, a member of the tumor necrosis factor (TNF) receptor family, has been implicated in T cell activation, T cell development and T-dependent antibody production by B cells. Its ligand CD70 has been identified only in humans, and, thus, physiological and pathological roles of the CD70-CD27 interaction remain to be determined in an experimental animal system. In the present study, we identified murine (m) CD70 by molecular cloning, and characterized its expression and function by generating an anti-mCD70 mAb. The mCD70 cDNA encoded a type II transmembrane glycoprotein of the TNF family, having 56.5% identity to the human CD70 amino acid sequence. The mCd70 gene was assigned in the central region of chromosome 17. To explore the expression and function of mCD70, we generated cDNA transfectants and anti-mCD70 mAb (FR70), which inhibited binding of a murine CD27-Fc fusion protein (mCD27-Ig) to mCD70 transfectants. FR70, as well as mCD27-Ig, immunoprecipitated a 30-33 kDa surface protein from A20 and mCD70-P815 cells but not from P815 cells. The mCD70 transfectants exhibited a potent co-stimulatory activity for antiCD3-stimulated T cell proliferation, which was blocked by FR70 far more efficiently than mCD27-Ig. FR70 also abrogated the CD28-independent co-stimulatory activity of A20 cells. The expression of mCD70 was detected on splenic T cells after stimulation with anti-CD3 and anti-CD28 mAb, and on splenic B cells after stimulation with anti-CD40 mAb. Cross-linking of surface Ig by anti-IgM mAb did not induce the mCD70 expression but enhanced the anti-CD40-induced mCD70 expression on splenic B cells. These results suggest a contribution of CD70 to murine T-B cognate interaction as proposed in the human system. FR70 will be useful for further investigating the physiological and pathological roles of the CD70-CD27 interaction in T cell development, T-dependent antibody production and various disease models in the murine system. [ABSTRACT FROM PUBLISHER]

Taking advantage of the recently demonstrated presence of N-aminopeptidases and the serine protease dipeptidyi aminopeptidase IV (DPP IV) at the surface of human myeloblastic HL-60 cells, the regulation of these protease activities in HL-60 cell differentiation has been assessed using combined spectrophotometric and flow cytometric assays. Addition of human recombinant granulocyte macrophage colony stimulating factor (rHu-GM-CSF) to HL-60 cells to induce differentiation into macrophages led to a time and dose-dependent increase in both cell surface N-aminopeptidase and DPP IV activities. Protease up-regulation was due to an enhancement in cell surface protease number, associated with a slight rise in apparent affinities of the enzymes for their substrates. In contrast, in HL-60 cells induced to differentiate into neutrophils in the presenceof retinoic acid, expression of cell surface N-amlnopeptidases was almost completely abolished in a time-and dose-dependent fashion, and this down-regulation was accompanied by a weak but significant decrease in affinity. However, no noticeable difference was seen in serine DPP IV expression between retinoic acid-treated and untreated HL-60 cells. Retinoic acid treatment also reduced soluble protease activity indicating that down-regulation of membrane aminopeptldases was not due to their proteolytic clip. No modulation in the activity of any of the enzymes tested was seen with human recombinant tumor necrosis factor- or retinol which do not induce HL-60 cell differentiation. The up-regulation of cell surface protease expression in HL-60 cells differentiated into macrophages was similar to that observed in monocytes isolated from peripheral blood: both DPP IV and N-aminopeptidase activities strictly increased on cells that undergo macrophage maturation (up to 5-fold) and independently of the nature of the differentiation inducer. Thus, the distinctive patterns of N-aminopeptidase and DPP IV expression that are seen in differentiating neutrophils and macrophages appear to be relatedto differences in stage of myeloid maturation. Because cell surface proteases are crucially involved in leukocyte functions, the data presented suggest that alterations in cell surface protease expression are associated with events controlling the differentiation of immature cells. [ABSTRACT FROM PUBLISHER]

Summary CD27 molecules are shown to be essential in the regulation of the death, activation and differentiation of T and B cells. However, the influence of CD27 on cytotoxic T-cell function remains obscure. Autologous EBV transformed B-cell lines (LCL), which highly express CD27 ligand CD70, here stimulated T cells and induced the cytotoxic T-lymphocyte (CTL) activity via T-cell antigen receptors (TCR). The cytotoxicity against LCL was diminished when anti-CD70 blocking MoAb was added initially in the culture. Resting T cells killed more CD70-transfected P815 cells than wild type P815 cells in the presence of anti-CD3 MoAb as measured by a 4-h 51 Cr release assay, and the cytotoxicity of both of the cell populations completely disappeared in the presence of concanamycin A (CMA). The expression of the perforin by the LCL-induced CTL in the presence of anti-CD70 blocking MoAb was diminished as compared with that without the blockage of CD27/CD70 interactions. The CTL induced by LCL did not kill Fas-transfected WR cells. CD27 signalling in the T cells did not affect Fas ligand (FasL) mRNA expression, LAK activity and IFN-γ synthesis in humans. Our data demonstrate that CD27/CD70 interactions enhance the cytotoxicity of CTL in the induction phase through enhancement of killing activity induced via the perforin-dependent mechanism, but not via the Fas/FasL system. [ABSTRACT FROM AUTHOR]