A novel heterophilic antibody interaction involves IgG4

IgG4 has been implicated in a diverse set of complex pathologies - e.g. autoimmune pancreatitis (AIP), idiopathic membranous nephropathy - and carries unique features including lack of activation of the classical complement pathway and a dynamic Fab-arm exchange. We recently showed that the rheumatoid factor (RF)-like activity of IgG4 is achieved through a hitherto unknown, Fc-Fc (and not Fab-Fc as is the case in classical RF; CRF) interaction; hence the name, novel RF (NRF). Here, we further explore the resemblance/difference between CRF and NRF. As heterophilic interactions of human IgM RF (CRF) are well known, we checked whether this is the case for IgG4. Human IgG4 showed variable reactivity to animal IgGs: reacting intensely with rabbit and mouse IgGs, but weakly with others. The binding to rabbit IgG was not through the Fab (as in CRF) but via the Fc piece, as was recently shown for human IgG (NRF). This binding correlates with the IgG4 concentration per se and could therefore be of diagnostic usage and incidentally explain some observed interferences in biological assays. In conclusion, here is defined a novel heterophilic antibody interaction and is established the universality of the unique Fc-Fc binding, both involving IgG4.

Slitrk1-deficient mice display elevated anxiety-like behavior and noradrenergic abnormalities

Mutations in SLITRK1 are found in patients with Tourette's syndrome and trichotillomania. SLITRK1 encodes a transmembrane protein containing leucine-rich repeats that is produced predominantly in the nervous system. However, the role of this protein is largely unknown, except that it can modulate neurite outgrowth in vitro. To clarify the role of Slitrk1 in vivo, we developed Slitrk1-knockout mice and analyzed their behavioral and neurochemical phenotypes. Slitrk1-deficient mice exhibited elevated anxiety-like behavior in the elevated plus-maze test as well as increased immobility time in forced swimming and tail suspension tests. Neurochemical analysis revealed that Slitrk1-knockout mice had increased levels of norepinephrine and its metabolite 3-methoxy-4-hydroxyphenylglycol. Administration of clonidine, an alpha2-adrenergic agonist that is frequently used to treat patients with Tourette's syndrome, attenuated the anxiety-like behavior of Slitrk1-deficient mice in the elevated plus-maze test. These results lead us to conclude that noradrenergic mechanisms are involved in the behavioral abnormalities of Slitrk1-deficient mice. Elevated anxiety due to Slitrk1 dysfunction may contribute to the pathogenesis of neuropsychiatric diseases such as Tourette's syndrome and trichotillomania.

Decoration of T-independent antigen with ligands for CD22 and Siglec-G can suppress immunity and induce B cell tolerance in vivo

Autoreactive B lymphocytes first encountering self-antigens in peripheral tissues are normally regulated by induction of anergy or apoptosis. According to the “two-signal” model, antigen recognition alone should render B cells tolerant unless T cell help or inflammatory signals such as lipopolysaccharide are provided. However, no such signals seem necessary for responses to T-independent type 2 (TI-2) antigens, which are multimeric antigens lacking T cell epitopes and Toll-like receptor ligands. How then do mature B cells avoid making a TI-2–like response to multimeric self-antigens? We present evidence that TI-2 antigens decorated with ligands of inhibitory sialic acid–binding Ig-like lectins (siglecs) are poorly immunogenic and can induce tolerance to subsequent challenge with immunogenic antigen. Two siglecs, CD22 and Siglec-G, contributed to tolerance induction, preventing plasma cell differentiation or survival. Although mutations in CD22 and its signaling machinery have been associated with dysregulated B cell development and autoantibody production, previous analyses failed to identify a tolerance defect in antigen-specific mutant B cells. Our results support a role for siglecs in B cell self-/nonself-discrimination, namely suppressing responses to self-associated antigens while permitting rapid “missing self”–responses to unsialylated multimeric antigens. The results suggest use of siglec ligand antigen constructs as an approach for inducing tolerance.

Investigation of the association between the GLC3A locus and normal tension glaucoma in Japanese patients by microsatellite analysis

Purpose:

To investigate whether the GLC3A locus harboring the CYP1B1 gene is associated with normal tension glaucoma (NTG) in Japanese patients.

Materials and Methods:

One hundred forty-two Japanese patients with NTG and 101 Japanese healthy controls were recruited. Patients exhibiting a comparatively early onset were selected as this suggests that genetic factors may show stronger involvement. Genotyping and assessment of allelic diversity was performed on 13 highly polymorphic microsatellite markers in and around the GLC3A locus.

Results:

There were decreased frequencies of the 444 allele of D2S0416i and the 258 allele of D2S0425i in cases compared to controls (P = 0.022 and P = 0.034, respectively). However, this statistical significance disappeared when corrected (Pc > 0.05). We did not find any significant association between the remaining 11 microsatellite markers, including D2S177, which may be associated with CYP1B1, and NTG (P > 0.05).

Conclusions:

Our study showed no association between the GLCA3 locus and NTG, suggesting that the CYP1B1 gene, which is reportedly involved in a range of glaucoma phenotypes, may not be an associated factor in the pathogenesis of NTG.

Interaction of Hepatic Chromatin with Androgen-Receptor Complex

When the chromatin prepared from male rat livers interacted with [3H] testosterone-receptor complex prepared from male rat livers, the binding was much higher than when interacted with free [3H] testosterone, indicating that the formation of testosterone-receptor complex is prerequisite for interaction with chromatin. When the [3H] testosterone-receptor complex was interacted with the chromatin and the bound chromatin proteins were extracted into three fractions based on their extractability or solubility in salt solutions, higher radioactivities were found in the 0.35 M NaCl-extract and 2.0 M NaCl residual fraction. Chromatin was fractionated into 0.35 M NaCl-soluble, 2.0 M NaCl-soluble and insoluble fractions, and interaction of free [3H] testosterone or [3H] testosterone-receptor complex with chromosomal fractions was studied. The binding of the chromosomal fractions with free [3H] testosterone was negligible compared with that of [3H] testosterone-receptor complex. The binding of 0.35 M NaCl-soluble fraction with [3H] testosterone-receptor complex was higher than that of 2.0 M NaCl-soluble fraction. The binding ability of 2.0 M NaCl-insoluble fraction with [3H] testosterone-receptor complex was twice as much as that of the intact chromatin. This observation indicated that salt-soluble fractions of chromatin contributes only partly to the binding of chromatin with [3H] testosterone-receptor complex and that other components in 2.0 M NaCl-insoluble fraction may participate in the binding.

Tolerability and safety of oral neratinib (HKI-272) in Japanese patients with advanced solid tumors

e14505

Background: Neratinib (HKI-272) is a potent irreversible pan-ErbB tyrosine kinase inhibitor. In non-Japanese pts, neratinib was found to have clinical activity against solid tumors and dose-limiting toxicity (DLT) of diarrhea. The maximum tolerated dose (MTD) was 320 mg daily and the recommended dose (RD) was 240 mg because of the diarrhea. In this phase 1 study, the MTD was determined and safety and preliminary efficacy were assessed in Japanese pts with advanced solid tumors. Methods: Pts (3- 6/cohort) received 80, 160, 240, or 320 mg oral neratinib. Each pt participated in only 1 dose group and received single doses of neratinib followed by 1 wk of observation; pts then received daily continuous administration at the same dose. DLTs were assessed from the first single dose to the end of 14 days of continuous treatment. Pharmacokinetics (PK) will be analysed via a noncompartmental method. Tumor measurements were made at screening and at the end of every 8 weeks (2 cycles) by RECIST. Results: Preliminary data for 21 pts as of 30 Oct 2008 are presented. Pts had a median age [range] of 61 yrs [39–78], were 62% male, and had all received ≥2 prior chemotherapy regimens. Tumor types at primary diagnosis were advanced colorectal (81%), breast (14%), and gastric (5%) cancer. Median duration of neratinib treatment [range] was 10 wks [3–29].Two patients at the 320-mg dose had DLTs of diarrhea plus anorexia. Therefore the MTD was determined to be 240 mg. Neratinib-related AEs, any grade in ≥25% of pts included diarrhea (95%), fatigue (67%), anorexia (43%), nausea (43%), abdominal pain (38%), decreased hemoglobin (38%), increased AST (33%), and rash (29%). Neratinib-related AEs, grade ≥3 in ≥1 pts were anorexia (3 pts) and diarrhea (2 pts). Two pts had partial response (PR), 8 pts had stable disease (SD) ≥8 wks, 2 had SD≥16 wks, 9 had progressive disease. The 2 pts with PR had ErbB-2+ advanced breast cancer. PK analysis is still ongoing. Conclusions: In Japanese pts, the MTD for neratinb was determined to be 240 mg and the RD will be confirmed as 240 mg. Neratinib is tolerable and demonstrates preliminary antitumor activity in pts with solid tumors.

[Table: see text]

Population data on 10 non-CODIS STR loci in Japanese population using a newly developed multiplex PCR system

This paper describes a newly devised autosomal short tandem repeat (STR) multiplex polymerase chain reaction (PCR) systems for 10 loci (D1S1656, D2S1353, D8S1132, D12S1090, D14S608, D18S535, D19S253, D20S480, D21S226, and D22S689) unlinked to the core STR loci (non-CODIS loci). Of 252 samples taken from the Japanese population, PCR products ranged in length from 107 bp to 319 bp. No significant deviations from Hardy-Weinberg equilibrium were observed at any of the 10 loci. The accumulated power of discrimination and power of exclusion for the 10 loci were 0.999999999998 and 0.99991, respectively. We conclude that the present multiplex system for the 10 non-CODIS loci represents a powerful tool for forensic applications.

Aberrant midsagittal fiber tracts in patients with hemimegalencephaly

BACKGROUND AND PURPOSE

In hemimegalencephaly, MR imaging often reveals midsagittal bandlike structures between the 2 lateral ventricles. To determine whether these structures are aberrant midsagittal fibers, we retrospectively reviewed them on conventional MR imaging and prospectively examined them by diffusion tensor MR and fiber tract (FT) reconstruction imaging.

MATERIALS AND METHODS

We retrospectively reviewed conventional MR images of 26 consecutive patients with hemimegalencephaly by 2 neuroradiologists, focusing on abnormal midsagittal structures. The distance between the 2 anterior horns and widths of midsagittal bandlike structures were measured. Prospective analysis was performed in 7 consecutive patients with hemimegalencephaly examined for midsagittal aberrant fibers by diffusion tensor imaging, and cortical distribution areas of the fibers were observed.

RESULTS

The distance between the 2 anterior horns was wide (>4 mm) due to white matter-intensity structures in 20 of 26 patients (76.9%). Mid-sagittal bandlike structures were observed in 15 patients (57.7%). Asymmetry of the fornices was detected in 7 patients (26.9%), and both fornices were thickened in 7 (26.9%) patients. On FT reconstruction, images showed that 4 of 7 patients with hemimegalencephaly had aberrant midsagittal fibers connecting frontal, occipital, or parietal lobes, bilaterally (n = 3) or ipsilaterally (n = 1). All 4 patients had increased width between the 2 anterior horns, and 3 of them exhibited midsagittal bandlike structures on conventional MR imaging. On the other hand, these MR imaging findings were not noted in 3 patients who did not have aberrant midsagittal fibers on diffusion tensor imaging.

CONCLUSIONS

Aberrant midsagittal FTs running intra- or interhemispherically do not infrequently exist in patients with hemimegalencephaly.

Lack of association of Toll-like receptor 9 gene polymorphism with Beh�et?s disease in Japanese patients

Toll-like receptors (TLRs) play an important role in the induction of defense mechanisms of the innate and adaptive immune responses to microbial pathogens. Genetic polymorphisms within the TLR9 gene have been reported to be associated with a variety of inflammatory and infectious diseases. Behçet's disease (BD) is a chronic inflammatory disease, and the etiology of BD has yet to be fully elucidated. We investigated the potential association of the TLR9 gene with susceptibility to BD by analyzing the frequency of nine single nucleotide polymorphisms (SNPs) in a population of 200 Japanese BD patients and 102 randomized controls. Our results showed that SNPs in the TLR9 gene were not significantly associated with susceptibility to BD.

Evaluation of miniY-STR multiplex PCR systems for extended 16 Y-STR loci

We developed three short amplicon Y-chromosomal short tandem repeat (miniY-STR) polymerase chain reaction multiplex systems for 16 Y-STR loci (DYS441, DYS446, DYS462, DYS481, DYS485, DYS495, DYS505, DYS510, DYS511, DYS549, DYS 575, DYS578, DYS593, DYS618, DYS638, and DYS643), using newly designed primer sets. In an assay of 238 Japanese males using the three miniY-STR systems, amplification product lengths ranged from 91 to 151 bp for all 16 Y-STR loci. We identified 212 different haplotypes among the 238 individuals, finding haplotype diversity and discrimination capacity of 0.9974 and 0.8908, respectively. An assay of degraded DNA samples using the three miniY-STR multiplex systems, including artificially degraded samples and degraded forensic casework samples, proved remarkably effective. In conclusion, analyses of miniY-STR multiplex systems will play an important role in forensic applications involving degraded DNA samples for which genotyping using only commercial kits is ill-suited.

Deletion of entire HLA-A gene accompanied by an insertion of a retrotransposon

Unusual HLA-A'null' alleles because of an entire gene deletion were found in three apparently unrelated Japanese families with leukemia patients. Inclusion of the entire HLA-A gene in the deletion was confirmed by polymerase chain reaction direct sequencing of the surrounding regions of HLA-A. Further localization of the breakpoints of the HLA-A deletion at the centromeric and telomeric sides was performed, and these families were shown to possess the identical deletion. We then determined the genomic sequence of the HLA-A-deleted haplotype. Surprisingly, the haplotype turned out to carry an insertion of an SVA (SINE-VNTR-Alu) retrotransposon of 2 kb as well as the 14 kb deletion that included the entire HLA-A gene.

Association between human polymorphic DNA markers and hypoxia adaptation in Sherpa detected by a preliminary genome scan

Genetic determinants of resistance to hypobaric hypoxia in the Sherpa are still unknown. Since adaptive gene variants must still be subjected to positive selection, linkage disequilibrium between such variants and specific alleles of flanking DNA markers is expected. Following this line of reasoning, we performed a human genome scan using 998 polymorphic DNA markers in 7 unrelated Sherpa porters living in the Solu-Khumbu area. This minimalist approach succeeded in detecting 8 DNA markers showing homozygosity for the same shared allele. Analysis of additional DNA samples from 2 more Sherpa porters focused our attention on three polymorphic DNA markers (D6S1697, D14S274, D17S1795) showing homozygosity for the same shared allele in 8 out 9 tested individuals. Analysis of DNA samples from Sherpa and non-Sherpa populations of Nepal proved HW equilibrium in both populations for markers D14S274 and D17S1795, while an excess of heterozygotes was observed in the Sherpa population for marker D6S1697. A significant difference in allele frequencies for D14S274 and D17S1795 between the two populations was observed. These findings exclude the possibility that homozygosity for 3 specific loci in 8 unrelated individuals might be ascribed to inbreeding or recent genetic drift. We therefore conclude that the chromosomal segments detected by such DNA markers may include genes involved in adaptation to hypobaric hypoxia.

MiniSTR multiplex systems based on non-CODIS loci for analysis of degraded DNA samples

We describe two short amplicon autosomal short tandem repeat (miniSTR) quadruplex systems for eight loci D1S1171, D2S1242, D3S1545, D4S2366, D12S391, D16S3253, D20S161, and D21S1437, unlinked from the combined DNA index system (non-CODIS) loci, using newly designed primer sets. The results of an assay of 411 Japanese individuals showed that polymerase chain reaction (PCR) products within the eight loci were less than 150bp in size, without the seven additional bases for adenylation. The frequency distributions in the loci showed no deviations from Hardy-Weinberg equilibrium expectations. The accumulated power of discrimination and power of exclusion for the eight loci were 0.9999999991 and 0.998, respectively. For assay of highly degraded DNA, including artificially degraded samples and the degraded forensic casework samples assessed with the present miniSTR quadruplex systems, the systems proved quite effective in analyzing degraded DNA.

MiniY-STR quadruplex systems with short amplicon lengths for analysis of degraded DNA samples

Two short amplicon Y-chromosomal short tandem repeat (miniY-STR) quadruplex systems for the eight Y-STR loci DYS522, DYS508, DYS632, DYS556, DYS570, DYS576, DYS504 and DYS540 were devised using newly designed primer sets. Among 224 samples from Japanese population, amplification product lengths detected in these Y-STR loci ranged from 95 to 147bp, while 170 different haplotype were identified (discrimination capacity=0.7589 and haplotype diversity=0.9949). As a result of test on degraded DNA samples using the miniY-STR quadruplex systems, the systems proved to be an quite effective tools for analyzing degraded DNAs. We conclude that analyses of the miniY-STR quadruplex systems in addition to the commercial available Y-STR multiplex kits are highly useful for forensic practices of degraded DNA samples.

Japanese population data for eight X-STR loci using two new quadruplex systems

Using two new X-chromosome short tandem repeats (X-STR) multiplex (quadruplex) systems, we investigated Japanese population data (drawn from 401 individuals) for eight X-STR loci (DXS10011, DXS9898, DXS8377, HPRTB, DXS7132, DXS6797, GATA172D05, and DXS6807). Allele typing with the systems was successful for all loci. The combined powers of discrimination of the eight loci in men and women were 0.999997 and 0.9999999996, respectively. We conclude that combined analyses of the eight X-STR loci using these two quadruplex polymerase chain reaction systems represent a powerful tool for Japanese forensic practice.

MiniX-STR multiplex system population study in Japan and application to degraded DNA analysis

We sought to evaluate a more effective system for analyzing X-chromosomal short tandem repeats (X-STRs) in highly degraded DNA. To generate smaller amplicon lengths, we designed new polymerase chain reaction (PCR) primers for DXS7423, DXS6789, DXS101, GATA31E08, DXS8378, DXS7133, DXS7424, and GATA165B12 at X-linked short tandem repeat (STR) loci, devising two miniX-multiplex PCR systems. Among 333 Japanese individuals, these X-linked loci were detected in amplification products ranging in length from 76 to 169 bp, and statistical analyses of the eight loci indicated a high usefulness for the Japanese forensic practice. Results of tests on highly degraded DNA indicated the miniX-STR multiplex strategies to be an effective system for analyzing degraded DNA. We conclude that analysis by the current miniX-STR multiplex systems offers high effectiveness for personal identification from degraded DNA samples.