Evaluating the risk of out-of-specification (OOS) occurrence before it happens is essential to prevent delays or interruptions in the supply of biological products. This study proposes a practical and quantitative evaluation approach using two indices, S1 and S2, as OOS risk screening and monitoring tools under finite-sample conditions. S1 evaluates whether the variability of data points in a dataset satisfies a low OOS risk criterion, defined as an acceptable level of inherent variability. S2 evaluates whether the observed data range remains within the specification limits with a range-proportional safety margin. Monte Carlo simulations based on normal distributions with sample sizes up to 500 demonstrated that S1 > 1 effectively identified datasets that deviated from the low OOS risk criterion, whereas S2 > 1 functioned as an early alert indicator that predicted or coincided with OOS occurrences. Regardless of the distribution type, both indices increase by definition as the spread of data points increases, suggesting their potential applicability as practical monitoring tools even for non-normal datasets. The combined use of S1 and S2 provides complementary and early warning insights into potential quality deviations and supports proactive quality risk management of biological products.

The human T-cell leukemia virus type 1 (HTLV-1), a retrovirus, integrates into host DNA and causes adult T-cell leukemia/lymphoma (ATL) in some individuals. Two types of defective proviruses, Type 1 and Type 2, are often observed in ATL cells. Here, we developed a 3-plex digital PCR (dPCR) method to detect HTLV-1 proviral deletions by comparing the ratios of copy numbers quantified using specific primer-probes for the LTR, pol, and pX regions. We analyzed HTLV-1-positive asymptomatic carriers (ACs) and AC samples at high risk for developing ATL due to high proviral load (ATL high-risk (HR) ACs) using dPCR. Deletions were identified in 11.8% (4/34, all Type 1) of ACs and 33.3% (7/21, Type 1:1, Type 2:6) of ATL HR ACs. dPCR analysis revealed that in three ATL samples, all exhibited Type 1 defective characteristics, and two showed extremely low ratios in the pol region. Clonality analysis of these two samples revealed high monoclonality, indicating monoclonal expansion of ATL cells with defective proviruses. These findings demonstrate that our method effectively detects defective proviruses in both ACs and ATL, providing a valuable tool for understanding the genomic characteristics of proviruses in these conditions.

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Membrane-binding proteins play a central role in various biological processes through interactions with the surface of biomembranes, which are intrinsically mobile and inhomogeneous. Therefore, unlike integral membrane proteins, membrane-bound protein structures tend to be inhomogeneous. In addition, large regions of membrane-binding proteins are exposed to the aqueous phase, resulting in broad distributions of global and local dynamic properties. In vitro, protein dynamics are influenced by the phase of biomimetic model membranes. Therefore, solution and solid-state NMR techniques must be used complementary to investigate the broad distribution of protein mobilities. Scalar- and dipolar coupling-based solid-state NMR techniques can characterize proteins that are strongly bound to the fluid and gel phases of membranes, respectively. Alternatively, advanced solution NMR techniques can be used to characterize proteins that are weakly bound to membranes.

Both natural viral infections and therapeutic interventions using viral vectors pose significant risks of malignant transformation. Monitoring for clonal expansion of infected cells is important for detecting cancer. Here we developed a novel method of tracking clonality via the detection of transgene integration sites. RAISING (Rapid Amplification of Integration Sites without Interference by Genomic DNA contamination) is a sensitive, inexpensive alternative to established methods. Its compatibility with Sanger sequencing combined with our CLOVA (Clonality Value) software is critical for those without access to expensive high throughput sequencing. We analyzed samples from 688 individuals infected with the retrovirus HTLV-1, which causes adult T-cell leukemia/lymphoma (ATL) to model our method. We defined a clonality value identifying ATL patients with 100% sensitivity and 94.8% specificity, and our longitudinal analysis also demonstrates the usefulness of ATL risk assessment. Future studies will confirm the broad applicability of our technology, especially in the emerging gene therapy sector.

C-reactive protein (CRP) and M-ficolin are the pattern recognition proteins of the innate immune system. In this report, a mixture of CRP and M-ficolin reversibly co-aggregated in a calcium-dependent manner. This coaggregation was enhanced at low pH (6.5) or low salt (35 mM NaCl) concentrations. The co-aggregate was dissolved by adding EDTA and reformed by adding calcium. The M-ficolin fibrinogen-like domain (FD1), the ligand-binding domain of M-ficolin, also showed calcium-dependent coaggregation with CRP, indicating that reversible coaggregation is caused by CRP interacting with FD1. Interestingly, adding phosphocholine (PC), the ligand of CRP, to a CRP-FD1 mixture abolished the reversible coaggregation activity. PC also inhibited the interaction between CRP and FD1. These results indicate that CRP retains PC-binding activity in the coaggregation state and that FD1 binds specifically to the PC-binding site on CRP but does not fully occupy the five PC-binding sites on a CRP pentamer as judged by SDS-PAGE analysis of precipitates. Coaggregation analysis using FD1 mutants showed that FD1 also retains ligand-binding activity in the coaggregation state and that coaggregation requires the trimeric form of FD1. It was also found that modifications to the ligand-binding site of FD1 affect coaggregation efficiency. Although the biological functions of the coaggregation activity of CRP and M-ficolin remain unresolved, the co-aggregates may function as bacteria-trapping particles with affinities for ligands of CRP and M-ficolin. In addition, coaggregation may be involved in CRP deposition in the lesions of several arterial diseases, such as atherosclerosis.

Approximately 10–20 million of Human T-cell leukemia virus type-1 (HTLV-1)-infected carriers have been previously reported, and approximately 5% of these carriers develop adult T-cell leukemia/lymphoma (ATL) with a characteristic poor prognosis. In Japan, Southern blotting has long been routinely performed for detection of clonally expanded ATL cells in vivo, and as a confirmatory diagnostic test for ATL. However, alternative methods to Southern blotting, such as sensitive, quantitative, and rapid analytical methods, are currently required in clinical practice. In this study, we developed a high-throughput method called rapid amplification of integration site (RAIS) that could amplify HTLV-1-integrated fragments within 4 h and detect the integration sites in > 0.16% of infected cells. Furthermore, we established a novel quantification method for HTLV-1 clonality using Sanger sequencing with RAIS products, and the validity of the quantification method was confirmed by comparing it with next-generation sequencing in terms of the clonality. Thus, we believe that RAIS has a high potential for use as an alternative routine molecular confirmatory test for the clonality analysis of HTLV-1-infected cells.

Background: Histamine fixed-immunoglobulin formulations, which consisted of 0.15 mu g of histamine dihydrochloride and 12 mu g of human immunoglobulin in a vial, are used for anti-allergic treatments, and controlling the amounts of histamine in the formulations is essential to avoid histamine intoxication. Objective: A high-performance liquid chromatography (HPLC) method for determination of histamine contents of the formulations was established and validated. Methods: Histamine extracted from the formulation was labeled with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate and was analyzed by gradient elution HPLC with UV detection at 260 nm. Results: The method showed linearity in the range 0.8-2.4 mu M (R > 0.999), accuracy (100.1-105.8% recovery), and precision (relative standard deviation <= 1.93%). The validated method was applied for five lots of the pharmaceutical, and their histamine contents were determined to be 0.149-0.155 mu g/vial. Conclusions: These results indicated that the validated method is useful to control amounts of histamine in biopharmaceutical products. Highlights: The HPLC method was developed for quantitative determination of histamine content of the histamine fixed-immunoglobulin formulations.

Several types of membrane proteins, including temporally bound peripheral membrane proteins, lipid-anchored proteins, and protein moieties protruding from the membrane surface, are biologically very important because of the presence of their functional moieties undergoing cell signaling, cytoskeletal rearrangement, and other processes at the membrane surfaces, although these structures have not yet been fully clarified because of their structural heterogeneity. It is emphasized that combined utilization of both solid-state and solution NMRSolution NMR experiments is essential to reveal their substantially varied dynamic structures. In this connection, structural features of amyloid proteins, α-synuclein (αS) and amyloid β (Aβ) protein, bound to membranes were also discussed in relation to their pathogenesis of respective amyloid diseases.

membrane-binding affinity of W231F, Trp231 is suggested to be excluded from the membrane-binding mechanism. Single-molecule raft function Gangliosides are considered to be strongly associated with rafts in cellular plasma membranes. However, how they interact with rafts and function in rafts have been unknown due to the lack of their fluorescent analogues that behave like the parent molecules. Here, we succeeded in synthesizing several fluorescent ganglioside probes. Surprisingly, single-molecule observation revealed that all the fluorescent ganglioside probes (GM1, GM2, GM3, GD1b) transiently formed homodimers which were induced by glyco-chain interactions and stabilized by raft-lipid interactions. Furthermore, we found that the homodimers inhibited dimerization of EGF receptors. Our results suggest that the transient homodimers are likely one of the basic unit for raft organization and function. attempt fabrication We These results suggest that the directional sensing implements a half-wave rectifier to filter out response to the back of the cAMP wave.

M-ficolin, which forms trimer-based multimers, is a pathogen-recognition protein in the innate immune system, and it binds to ligands through its fibrinogen-like (FBG) domain. As the first step toward the elucidation of the molecular basis for pathogen-recognition by the M-ficolin multimers, we assigned the backbone resonances of the monomeric mutant of the M-ficolin FBG domain, recombinantly expressed by Brevibacillus choshinensis. Like the wild-type trimeric FBG domain, the monomeric FBG domain also requires His251, His284 and His297 for the ligand-binding activity, as judged by mutational analyses using zonal affinity chromatography. The secondary structure predicted by the backbone resonance assignments is similar to that of the trimeric FBG domain in the crystal, indicating that the monomeric FBG domain is folded correctly to perform its function.

Protein activities are generally regulated by intramolecular allosteric interactions, by which spatially separated sites in a protein molecule communicate. Intramolecular allosteric interactions in the phospholipase C (PLC)-δ1 pleckstrin homology (PH) domain were investigated by solution NMR spectroscopy for selectively [α-(15)N]Lys-labeled proteins. The results of NMR analyses indicated that the binding of inositol 1,4,5-trisphosphate (IP3) to the protein induces local environmental changes at all lysine residues, including residues such as Lys-43 spatially separated from the specific IP3 binding site consisting of Lys-30, Lys-32, and Lys-57. IP3 binding also induces conformational stabilization of a characteristic short α-helix (α2) from residues 82 to 87. Mutational analyses indicated that an interaction network mainly consisting of the side chains of Lys-30, Lys-32, and Lys-43 exists in the ligand-free protein, and it was therefore predicted that binding of IP3 to the specific site modifies the interaction network, resulting in formation of a new interaction network, in which the side chains of Lys-57 and Phe-87 contribute to stable IP3 binding. These results provide evidence for intramolecular interactions in the PLC-δ1 PH domain, the function of which could be allosterically regulated by modifications at sites spatially separated from the ligand-binding site through the intramolecular interaction network.

Liposomes, a kind of artificial cells, have been used for studies of biomembranes and membrane proteins.However, liposomes without support are weak physically.Therefore, Supported Lipid Bilayer (SLB) was developed, mostly on planar supports.In this respect, we are trying to develop a closed supported lipid bilayer.We used Sephadex as the support, having glutathione linker, and PutP (E.coli Na + /proline symporter)-GST fusion protein as a membrane protein.After reconstitution with E.coli phospholipid, the Sephadex beads seemed to be closed and showed Uptake activity of proline, suggesting that we obtained a closed supported artificial cell.