Regulatory Role for Complement Receptors (CD21/CD35) in the Recombination Activating Gene Expression in Mouse Peripheral B Cells

A population of peripheral B cells have been shown to express recombination activating gene products, RAG-1 and RAG-2, which are considered to be involved in revising the B cell antigen receptor (BCR) in the periphery. BCR engagement has been reported to turn off RAG expression in peripheral B cells, whereas the same treatment has an opposite effect in immature B cells in the bone marrow. In contrast to receptor editing that is involved in the removal of autoreactivity in immature B cells, it has been shown that secondary V(D)J rearrangement in peripheral B cells, termed receptor revision, contributes to affinity maturation of antibodies. Here, we show that RAG-2 expression in murine splenic B cells was abrogated by the coligation of BCR with complement receptors (CD21/CD35) much more efficiently than by the engagement of BCR alone. On the other hand, the same coligation augmented proliferation of anti-CD40-stimulated B cells. Consistent with these observations, RAG-2 expression was lower in the draining lymph nodes of the quasi-monoclonal mice when they were immunized with a high-affinity antigen than with a low-affinity one. These findings suggest a crucial role for CD21/CD35 in directing the conservation or the revision of BCRs in peripheral B cells

Effectiveness of SSRIs for GAD in children

Generalized anxiety disorder (GAD) sometimes exists in the background of social withdrawal and school refusal. Although clinical evidence suggests that selective serotonin reuptake inhibitors (SSRIs) are an effective treatment for GAD, they are not officially approved for GAD in Japan. In addition, it has been established that the use of SSRIs increases the risk for suicide and activation syndrome among young individuals. As such, there is currently little domestic clinical experience in prescribing SSRIs to young patients with GAD. The authors report two cases involving 10-year-old patients with GAD who were treated successfully with escitalopram and experienced subsequent improvement in social withdrawal and school refusal. One patient had autistic spectrum disorder and exhibited self-harm associated with anxiety symptoms, requiring careful use of SSRIs under hospitalization. The other patient was treated at an outpatient clinic without any side effects. In each case, improvement of anxiety symptoms with the use of SSRIs facilitated the introduction of psychoeducation and psychotherapy. It is important to accurately diagnose GAD, which may exist in the background of patients exhibiting social withdrawal and school refusal, and to treat the disorder appropriately

Generation of IgM and IgG1 monoclonal antibodies with identical variable regions: comparison of avidity

Generally, IgM antibodies (Abs) produced in a primary immune response show lower affinity for an inducing antigen (Ag) compared with the corresponding IgG Abs that are major switched isotypes formed in the secondary response. An IgM molecule is a pentamer with 10 Ag-binding sites that will contribute to an increase of avidity for an Ag. To estimate the contribution of the pentameric structure to the avidity of an IgM Ab, we generated IgM and IgG1 monoclonal Abs (mAbs) with identical V regions that are specific for 4-hydroxy-3-nitrophenylacetyl (NP) by in vitro class switching of B cells followed by the cell fusion with a mouse myeloma cell line. Compared with an anti-NP IgG1 mAb, the corresponding IgM mAb showed much higher avidity for NP-conjugated bovine serum albumin, which was drastically reduced after being dissociated into monomers

Genetic manipulation of an exogenous non-immunoglobulin protein by gene conversion machinery in a chicken B cell line

During culture, a chicken B cell line DT40 spontaneously mutates immunoglobulin (Ig) genes by gene conversion, which involves activation-induced cytidine deaminase (AID)-dependent homologous recombination of the variable (V) region gene with upstream pseudo-V genes. To explore whether this mutation mechanism can target exogenous non-Ig genes, we generated DT40 lines that bears a gene conversion substrate comprising the green fluorescent protein (GFP) gene as a donor and the blue fluorescent protein (BFP) gene as an acceptor. A few percent of the initially BFP-expressing cells converted their fluorescence from blue to green after culture for 2–3 weeks when the substrate construct was integrated in the Ig light chain locus, but not in the ovalbumin locus. This was the result of AID-dependent and the GFP gene-templated gene conversion of the BFP gene, thereby leading to the introduction of various sizes of GFP-derived gene segment into the BFP gene. Thus, G/B construct may be used to visualize gene conversion events. After switching off AID expression in DT40 cells, the mutant clones were isolated stably and maintained with their mutations being fixed. Thus, the gene conversion machinery in DT40 cells will be a useful means to engineer non-Ig proteins by a type of DNA shuffling

A new adrenal computer imaging technique using dual-radioisotopes.

Computer processed adrenal imaging using dual-radioisotopes, 6 beta-iodomethyl-19-nor-cholest-5(10)-en-3 beta-ol-131I and 99mTc-phytate was performed in 12 patients with primary aldosteronism and 4 with Cushing's syndrome due to adrenocortical tumor. Adreno-photoscanning and hepato-photoscanning were performed in the same position 2-4 days following intravenous administration of radiocholesterol. The scintigraphic information was stored on cassettes and scan subtraction and a digital-computer method for data smoothing were performed on an oscilloscope. The tumor site could be determined in all cases until day 4 by this computer processed image.</p

Regulatory Role for Complement Receptors (CD21/CD35) in the Recombination Activating Gene Expression in Mouse Peripheral B Cells

A population of peripheral B cells have been shown to express recombination activating gene products, RAG-l and RAG-2, which are considered to be involved in revising the B cell antigen receptor (BCR) in the periphery. BCR engagement has been reported to tum off RAG expression in peripheral B cells, whereas the same treatment has an opposite effect in immature B cells in the bone marrow. In contrast to receptor editing that is involved in the removal of autoreactivity in immature B cells, it has been shown that secondary V(D)J rearrangement in peripheral B cells, termed receptor revision, contributes to affinity maturation of antibodies. Here, we show that RAG-2 expression in murine splenic B cells was abrogated by the coligation of BeR with complement receptors (CD211CD35) much more efficiently than by the engagement of BCR alone. On the other hand, the same coligation augmented proliferation of anti-CD40-stimulated B cells. Consistent with these observations, RAG-2 expression was lower in the draining lymph nodes of the quasi-monoclonal mice when they were immunized with a high-affinity antigen than with a low-affinity one. These findings suggest a crucial role for CD211CD35 in directing the conservation or the revision of BCRs in peripheral B cells

Association of schizophrenia onset age and white matter integrity with treatment effect of D-cycloserine : a randomized placebo-controlled double-blind crossover study

Background: It has been reported that drugs which promote the N-Methyl-D-aspartate-type glutamate receptor function by stimulating the glycine modulatory site in the receptor improve negative symptoms and cognitive dysfunction in schizophrenia patients being treated with antipsychotic drugs. Methods: We performed a placebo-controlled double-blind crossover study involving 41 schizophrenia patients in which D-cycloserine 50 mg/day was added-on, and the influence of the onset age and association with white matter integrity on MR diffusion tensor imaging were investigated for the first time. The patients were evaluated using the Positive and Negative Syndrome Scale (PANSS), Scale for the Assessment of Negative Symptoms (SANS), Brief Assessment of Cognition in Schizophrenia (BACS), and other scales. Results: D-cycloserine did not improve positive or negative symptoms or cognitive dysfunction in schizophrenia. The investigation in consideration of the onset age suggests that D-cycloserine may aggravate negative symptoms of early-onset schizophrenia. The better treatment effect of D-cycloserine on BACS was observed when the white matter integrity of the sagittal stratum/ cingulum/fornix stria terminalis/genu of corpus callosum/external capsule was higher, and the better treatment effect on PANSS general psychopathology (PANSS-G) was observed when the white matter integrity of the splenium of corpus callosum was higher. In contrast, the better treatment effect of D-cycloserine on PANSS-G and SANS-IV were observed when the white matter integrity of the posterior thalamic radiation (left) was lower. Conclusion: It was suggested that response to D-cycloserine is influenced by the onset age and white matter integrity

Transmission of Specific Genotype Streptomycin Resistant Strains of Mycobacterium tuberculosis in the Tokyo Metropolitan Area in Japan

<p>Abstract</p> <p>Background</p> <p>From 2003 through to 2004, an outbreak of tuberculosis was identified at a university campus in Yokohama City, located in the southern part of the Tokyo Metropolitan Area (TMA). All <it>Mycobacterium tuberculosis </it>(<it>M. tuberculosis</it>) strains detected with regards to this outbreak turned out to be Streptomycin resistant with matched patterns of 14 IS<it>6110 </it>bands of Restriction Fragment Length Polymorphism (RFLP). The <it>M. tuberculosis </it>bacilli, which had the matched IS<it>6110 </it>band patterns with resistance to Streptomycin to those of bacilli isolated in the outbreak, were also concurrently detected through either the population-based or the hospital-based DNA fingerprinting surveillance of <it>M. tuberculosis </it>either in Shinjuku City or in Kawasaki City respectively.</p> <p>The aim of the present study is to describe the spread of the specific genotype strains of <it>M. tuberculosis </it>in the TMA as observed in the above incident, and to identify the possible transmission routes of the strains among people living in urban settings in Japan.</p> <p>Methods</p> <p>We applied Variable Numbers of Tandem Repeats (VNTR) analysis to all <it>M. tuberculosis </it>isolates which were resistant to Streptomycin with a matched IS<it>6110</it>-RFLP band pattern (M-strains). They were isolated either from cases related to the tuberculosis outbreak that happened at a university, or through DNA fingerprinting surveillance of <it>M. tuberculosis </it>both in Shinjuku City and in Kawasaki City. For VNTR analysis, 12MIRU loci, 4ETR loci, seven loci by Supply, four loci by Murase (QUB15, Mtub24, VNTR2372, VNTR3336) were selected.</p> <p>Results</p> <p>Out of a total of 664 isolates collected during the study period, 46 isolates (6.9%) were identified as M-strains. There was a tendency that there was a higher proportion of those patients whose isolates belonged to M4-substrains, with four copies of tandem repeat at the ETR-C locus, to have visited some of the internet-cafés in the TMA than those whose isolates belonged to M5-substrains, with five copies at the ETR-C locus, although statistically not significant (38.1% vs. 10.0%, Exact p = 0.150).</p> <p>Conclusion</p> <p>Although firm conclusions could not be reached through the present study, it suggested that we have to take into consideration that tuberculosis can be transmitted in congregated facilities like internet cafés where tuberculosis high-risk people and general people share common spaces.</p

Phamacogenomics of Clozapine-Induced Agranulocytosis

Background: Clozapine-induced agranulocytosis (CIA)/clozapine-induced granulocytopenia (CIG) (CIAG) is a life-threatening event for schizophrenic subjects treated with clozapine. Methods: To examine the genetic factor for CIAG, a genome-wide pharmacogenomic analysis was conducted using 50 subjects with CIAG and 2905 control subjects. Results: We identified a significant association in the human leukocyte antigen (HLA) region (rs1800625, p = 3.46 × 10−9, odds ratio [OR] = 3.8); therefore, subsequent HLA typing was performed. We detected a significant association of HLA-B*59:01 with CIAG (p = 3.81 × 10−8, OR = 10.7) and confirmed this association by comparing with an independent clozapine-tolerant control group (n = 380, p = 2.97 × 10−5, OR = 6.3). As we observed that the OR of CIA (OR: 9.3~15.8) was approximately double that in CIG (OR: 4.4~7.4), we hypothesized that the CIG subjects were a mixed population of those who potentially would develop CIA and those who would not develop CIA (non-CIA). This hypothesis allowed the proportion of the CIG who were non-CIA to be calculated, enabling us to estimate the positive predictive value of the nonrisk allele on non-CIA in CIG subjects. Assuming this model, we estimated that 1) ~50% of CIG subjects would be non-CIA; and 2) ~60% of the CIG subjects without the risk allele would be non-CIA and therefore not expected to develop CIA. Conclusions: Our results suggest that HLA-B*59:01 is a risk factor for CIAG in the Japanese population. Furthermore, if our model is true, the results suggest that rechallenging certain CIG subjects with clozapine may not be always contraindicated