Mouse IgG Research Articles

Everything's under Control: Maximizing Biosensor Performance through Negative Control Probe Selection.

The rapid rise of label-free biosensing technologies has led to multiple creative strategies for the detection of macromolecules in complex biological solutions for disease state monitoring, drug discovery, and basic science research. A challenge with these techniques is that assays conducted in complex media such as serum suffer from nonspecific binding of matrix constituents. In label-free biosensors, it is virtually impossible to distinguish these nonspecific interactions without the use of a reference (negative control) probe. Only with reference subtraction can the specific binding signal be faithfully reported. To date, this has been a sparsely studied area in the biosensing field. Here, we report an FDA-inspired framework for optimum control probe selection and a systematic analysis for determining the optimal negative control probe given two monoclonal antibody capture probes on photonic ring resonator sensors. Briefly, while the differences in assay performance for IL-17A and CRP were found to be subtle, the best-scoring reference control based on the bioanalytical parameters of linearity, accuracy, and selectivity differed for each analyte. In the IL-17A assay, BSA scored the highest at 83%, while mouse IgG1 isotype control antibody placed a close second with 75%. With respect to the CRP assay, the rat IgG1 isotype control antibody scored the highest at 95%, while anti-FITC scored the second highest at 89%. These results suggest that although isotype-matching to the capture antibody may be tempting, the best on-chip reference control must be optimized on a case-by-case basis using the framework we report.

Antitumor Activities of a Humanized Cancer-Specific Anti-HER2 Monoclonal Antibody, humH2Mab-250 in Human Breast Cancer Xenografts

Monoclonal antibody (mAb) and cell-based immunotherapies represent cutting-edge strategies for cancer treatment. However, safety concerns persist due to the potential targeting of normal cells that express reactive antigens. Therefore, it is crucial to develop cancer-specific mAbs (CasMabs) that can bind to cancer-specific antigens and exhibit antitumor activity in vivo, thereby reducing the risk of adverse effects. We previously screened mAbs targeting human epidermal growth factor receptor 2 (HER2) and successfully developed a cancer-specific anti-HER2 mAb, H2Mab-250/H2CasMab-2 (mouse IgG1, kappa). In this study, we assessed both the in vitro and in vivo antitumor efficacy of the humanized H2Mab-250 (humH2Mab-250). Although humH2Mab-250 showed lower reactivity to HER2-overexpressed Chinese hamster ovary-K1 (CHO/HER2) and breast cancer cell lines (BT-474 and SK-BR-3) than trastuzumab in flow cytometry, both humH2Mab-250 and trastuzumab showed similar antibody-dependent cellular cytotoxicity (ADCC) against CHO/HER2 and the breast cancer cell lines in the presence of effector splenocytes. In addition, humH2Mab-250 exhibited significant complement-dependent cellular cytotoxicity (CDC) in CHO/HER2 and the breast cancer cell lines compared to trastuzumab. Furthermore, humH2Mab-250 possesses compatible in vivo antitumor effects against CHO/HER2 and breast cancer xenografts with trastuzumab. These findings highlight the distinct roles of ADCC and CDC in the antitumor effects of humH2Mab-250 and trastuzumab and suggest a potential direction for the clinical development of humH2Mab-250 for HER2-positive tumors.

SERS-based quantitative vertical flow assay using dual Au-Ag SERS nanoprobes

A surface-enhanced Raman scattering (SERS)-based vertical flow assay (VFA) platform was developed for the point-of-care testing (POCT) to perform multiplex diagnosis and distinguish each disease with similar symptoms (e.g., analysis of respiratory diseases including SARS-CoV-2, influenza and RSV). To evaluate the feasibility of multiplexing performance of SERS-VFA platform, vertical flow cartridges with 2 × 2 test areas on the nitrocellulose membrane and two different Raman reporter-labeled SERS nanoprobes were prepared, to detect samples including two different immunoglobulins (mouse IgG and rabbit IgG). For the preparation of SERS nanoprobes, we made use of the gold-silver/core–shell metal nanostructures for the local electromagnetic-field enhancement effect, and the Raman signal could be improved. SERS mapping images for each IgG in the sample were generated by measuring Raman peak position originated from each individual SERS nanoprobes. As a result, the quantitative analysis of each individual IgG could be performed at once, with a single sample. The detection limit for each rabbit IgG and mouse IgG was calculated as 0.030 μg/mL and 0.18 μg/mL, respectively. This result shows the SERS-based VFA platform could be of significant utility in multiplexed detection of chemical or biological targets.

Development of high-performance inducible and secretory expression vector and host system for enhanced recombinant protein production

The production of lipopolysaccharide (LPS)-free recombinant proteins from culture supernatants is of great interest to biomedical research and industry. Due to the LPS-free cell wall structure and the well-defined secretion factor B (SecB)-dependent secretion pathway, Gram-positive bacteria are a superior alternative to Escherichia coli expression systems. However, the lack of inducible expression systems for high yields has been a bottleneck. To address this, we developed the pKS81 plasmid, featuring the uhpT (glucose-6-phosphate [G6P] transporter) promoter for high expression of recombinant proteins induced by extracellular G6P via a three-component hexose phosphate transport regulatory system (HptARS), the N-terminal SecB-dependent signal peptide sequence for recombinant protein secretion, and the C-terminal 8 × histidine tag for purification by nickel affinity chromatography. We also generated an expression host strain, Staphylococcus aureus LAC9, lacks the uhpT gene and harmful superantigen and leukotoxin genes, allowing for constitutive HptARS activation by extracellular G6P and increased safety, respectively. Using the pKS81 plasmid, we successfully achieved high yields of prokaryotic (staphylococcal leukotoxin E) and eukaryotic (human annexin A2 protein tagged with mouse IgG1) recombinant proteins, up to 900 mg/L. Our newly established inducible and secretory expression system provides for efficient production and easy purification of LPS-free recombinant proteins, making it valuable for biomedical research and industrial applications.

Serotype-Specific Dengue Virus IgG Assay Using EDIII-Based Recombinant Proteins and Its Application in an Endemic Population in Northeast Brazil.

Dengue is the most prevalent arboviral disease globally, with Brazil currently experiencing a significant rise in cases. Dengue virus (DENV) typically co-circulates with other clinically and antigenically similar flaviviruses, such as Zika virus (ZIKV). The clinical diagnosis is difficult and accurate serological analysis represents an unmet challenge. Traditionally, serological analysis of DENV infection focuses on the acute phase via detection of NS1 or IgM. Developing IgG DENV-specific assays has been defiant due to the co-circulation of four antigenically distinct serotypes and a strong cross-reactivity with other arboviruses, particularly with ZIKV. The goal of this study was to produce recombinant domain III of the Envelope (EDIII) proteins of each DENV serotype and ZIKV and evaluate the ability to detect specific IgG antibodies. The antigens were tested on the ELISA platform to measure DENV-specific IgG in mice and patients infected with ZIKV and DENV. The assay differentiated serotype-specific IgG responses in susceptible mice (AG129) experimentally infected with DENV or ZIKV. In addition, the test demonstrated a robust performance achieving 87.8% sensitivity and 91.4% specificity when tested against 648 well-characterized sera collected from humans infected with DENV and/or ZIKV. The test was further applied to serum samples collected from 318 healthy individuals from an endemic region in Northwest/Central Brazil, without a previous diagnosis of DENV, and revealed that 65% of the samples reacted with at least one DENV serotype antigen, including 123 monotypic samples (88 for DENV-1) and 90 samples reacting with multiple antigens. Collectively, these results indicate that the IgG DENV-EDIII ELISA is a valuable tool for assessing the serological status of populations in endemic areas, particularly in regions where other flaviviruses, particularly ZIKV, co-circulate and offer support to establish public health policies against the disease.

Intranasal trivalent candidate vaccine induces strong mucosal and systemic immune responses against Neisseria gonorrhoeae.

The spread of multidrug-resistant strains of Neisseria gonorrhoeae poses a great challenge in gonorrhea treatment. At present, vaccination is the best strategy for gonorrhea control. However, given the extensive antigenic variability of N. gonorrhoeae, the effectiveness of monovalent vaccines is limited. Therefore, increasing the coverage of vaccination by using a multivalent vaccine may be more effective. In this study, a trivalent vaccine comprising three conserved antigens, namely, the App passenger domain, MetQ, and neisserial heparin binding antigen (NHBA), was constructed, and its protective effect was evaluated. Trivalent vaccines induced stronger circulating IgG and IgA antibody responses in mice than monovalent vaccines, in addition to eliciting Th1, Th2, and Th17 immune responses. Antiserum generated by the trivalent vaccine killed N. gonorrhoeae strains (homologous FA1090 and heterologous FA19), exhibiting superior bactericidal capacity than NHBA and MetQ vaccine antisera against N. gonorrhoeae, but similar capacities to those of the App vaccine antiserum. In addition, the trivalent vaccine antiserum achieved greater inhibition of N. gonorrhoeae FA1090 strain adherence to ME-180 cells compared to that elicited by the monovalent vaccine antiserum. In a mouse vaginal infection model, the trivalent vaccine was modestly effective (9.2% decrease in mean area under curve compared to the pCold-TF control mice), which was somewhat better than the protection seen with the monovalent vaccines. Our findings suggest that recombinant multivalent vaccines targeting N. gonorrhoeae exhibit advantages in protective efficacy compared to monovalent vaccines, and future research on multivalent vaccines should focus on optimizing different antigen combinations.

Preliminary Study on Type I Interferon as a Mucosal Adjuvant for Human Respiratory Syncytial Virus F Protein.

Background: Human respiratory syncytial virus (HRSV) imposes a significant disease burden on infants and the elderly. Intranasal immunization using attenuated live vaccines and certain vector vaccines against HRSV has completed phase II clinical trials with good safety and efficacy.Recombinant protein vaccines for mucosal immunization require potent mucosal adjuvants. Type I interferon (IFN), as a natural mucosal adjuvant, significantly enhances antigen-presenting cell processing and antigen presentation, promoting the production of T and B cells. Methods: This study utilized human α2b interferon (IFN-human) and mouse α2 interferon (IFN-mouse) as nasal mucosal adjuvants in combination with fusion protein (F). Intranasal immunization was performed on BALB/c mice to evaluate the immunogenicity of the formulation in vivo. Results: Compared to the F protein immunization group, mice in the F + IFN-Human and F + IFN-Mouse experimental groups exhibited significantly increased neutralizing antibody titers and augmented secretion of IFN-γ and IL-4 by lymphocytes, and both of them could induce the production of high-titer specific IgA antibodies in mice (p < 0.001).The F + IFN-Human immunization induced the highest IgG and IgG1 antibody titers in mice; however, the F + IFN-Mouse immunization group elicited the highest neutralizing antibody titers (598), lowest viral loads in the lungs (Ct value of 31), and fastest weight recovery in mice. Moreover, mice in the F + IFN-Mouse immunization group displayed the mildest lung pathological damage (Total score of pathological injury was 2). Conclusions: In conclusion, IFN-Mouse, as a mucosal adjuvant for HRSV recombinant protein vaccines, demonstrated superior protective effects in mice compared to IFN-Human adjuvants.

Extraction and Identification of Polysaccharide from Lentinus edodes and Its Effect on Immunosuppression and Intestinal Barrier Injury Induced by Cyclophosphamide.

Lentinus edodes serves as a significant source of both medicine and food, with its key component, lentinan (LNT), recognized as an effective immunomodulator. However, the mechanisms by which it regulates immune and intestinal functions under conditions of immunosuppression remain unclear. This study aims to investigate the components of lentinan and examine its potential effects on countering cyclophosphamide (CP)-induced immunosuppression, intestinal barrier damage, and dysregulation of gut microbiota. In this study, the effects of LNT were evaluated by serological indicators, histopathological changes in ileum, tight-junction-related protein expression, cytokine expression levels, and gut microbiota 16S rRNA gene sequencing. We found that LNT was effective in mitigating the abnormalities in body weight, immune organ index, and serum levels of IL-6, IL-2, IFN-γ, and IgG in mice induced by CP (p < 0.05). Furthermore, LNT demonstrated the ability to alleviate intestinal barrier damage induced by CP by increasing the mRNA levels of TNF-α, IL-1β, IFN-γ, Occludin, and ZO-1 (p < 0.05). Additionally, 16S rRNA gene sequencing revealed that LNT also normalized the disrupted abundance of Firmicutes, Proteobacteria, and Bacteroidets caused by CP. This restoration brought the gut microbiota back to normal levels and increased the abundance of certain tumor-inhibiting bacteria, such as Alistipes. Overall, lentinan demonstrated the ability to reverse the immunosuppressive effects induced by cyclophosphamide and modulate gut microbiota to restore a healthy microbial balance.

Proposal of a Rapid Detection System Using Image Analysis for ELISA with an Autonomous Centrifugal Microfluidic System.

In this study, with the aim of adapting an enzyme-linked immunosorbent assay (ELISA) system for point-of-care testing (POCT), we propose an image analysis method for ELISAs using a centrifugal microfluidic device that automatically executes the assay. The developed image analysis method can be used to quantify the color development reaction on a TMB (3,3',5,5'-tetramethylbenzidine) substrate. In a conventional ELISA, reaction stopping reagents are required at the end of the TMB reaction. In contrast, the developed image analysis method can analyze color in the color-developing reaction without a reaction stopping reagent. This contributes to a reduction in total assay time. The microfluidic devices used in this study could execute reagent control for ELISAs by steady rotation. In the demonstration of the assay and image analysis, a calibration curve for mouse IgG detection was successfully prepared, and it was confirmed that the image analysis method had the same performance as the conventional analysis method. Moreover, the changes in the amount of color over time confirmed that a calibration curve equal to the endpoint analysis was obtained within 2 min from the start of the TMB reaction. As the assay time before the TMB reaction was approximately 7.5 min, the developed ELISA system could detect TMB in just 10 min. In conventional methods using a plate reader, the assay required a time of 90 min for manual handling using microwell plates, and in the case of using automatic microfluidic devices, 30 min were required. The time of 10 min realized by this proposed method is equal to the time required for detection in an immunochromatographic assay with a lateral flow assay; therefore, it is expected that ELISAs can be performed sufficiently to adapt to POCT.

Pathogenesis-related protein, thaumatin-like protein 1b is a transdermal sensitizing allergen of mango fruits in mouse models

ABSTRACT Food allergens can enter the skin and increase the susceptibility to food allergies by producing immunoglobulin (Ig) E. Mango is a popular fruit worldwide and known to be allergenic. Dermal sensitization may occur around the oral cavity during ingestion of mangoes. However, to date, no allergenic proteins in mangoes have been shown to cause dermal sensitization in humans or animal models. Therefore, we aimed to identify mango proteins that sensitize mice percutaneously. The occiput of BALB/c mice was shaved, and a crude mango extract containing sodium dodecyl sulfate was applied to the skin. Mango protein-specific IgE and IgG1 were produced in response to this treatment. Proteins in mangoes that bind to mouse IgG1 and IgE were purified and identified as thaumatin-like protein 1b (TLP1b). This is the first study to identify TLP1b, a pan-allergen belonging to a family of pathogenesis-related proteins, as a mango allergen causing transdermal sensitization in mice.

Chromone components of Saposhnikovia divaricate attenuate rheumatoid arthritis development by inhibiting the inflammatory response

Ethnopharmacological relevanceSaposhnikovia divaricata (Turcz.) Schisck., a traditional Chinese medicine (TCM), has historically been utilized in the clinical treatment of RA. It was initially documented in the 'Shennong Ben Cao Jing' as a superior quality, with the text stating: 'The herb is widely renowned for its efficacy in alleviating whole-body discomfort, bone pain, malaise, and promoting long-lasting vitality. Chromones (CHR) were identified as the primary active components in Saposhnikovia divaricata. However, the specific molecular mechanisms by which CHR impacts RA remain incompletely understood. Aim of the studyTo explore the therapeutic efficacy of CHR, a class of compound derived from Saposhnikovia divaricata, in alleviating arthropathy and immune hyperactivity in a collagen-induced arthritis (CIA) mouse model. Material and methodsSurface plasmon resonance (SPR) molecular fishing and UHPLC-QTOF/MS technology were used to identify CHR in Saposhnikovia divaricata as an active ingredient for treating RA. A CIA mouse model was used to verify the anti-RA effect of CHR in vivo. The anti-RA efficacy of CHR in vivo was evaluated by body weight change, joint swelling, arthritis index, immune organ index, ankle joint disease, and immunoglobulin G (IgG) content. The mechanism of improving RA was further analyzed by a protein chip assay and verified by Western blotting. ResultsCHR treatment reduced swelling, arthritis index, and IgG, IgG1, IgG2a, and IgG2b levels in CIA mice. Protein microarray indicated that CHR mitigated CIA-induced joint inflammation by inhibiting immune cell activation, reducing the expression of inflammatory factors and chemokines, potentially by modulating the rheumatoid arthritis pathway involving tumor necrosis factor-α (TNF-α), interleukin-17 (IL-17), and chemokines. This hypothesis was supported by the upregulation of bone morphogenetic proteins 3 (BMP3) and phospho-Smad2 (p-Smad2) proteins, coupled with the downregulation of interleukin-6 (IL-6), interleukin-1β (IL-1β), TNF-α, and IL-17A proteins in the joints of CHR-treated mice. ConclusionCHR shows promise as a potential therapeutic agent for RA, exerting its effects through anti-inflammatory mechanisms.

Molecular Imaging of p53 in Mouse Models of Cancer Using a Radiolabeled Antibody TAT Conjugate with SPECT.

Mutations of p53 protein occur in over half of all cancers, with profound effects on tumor biology. We present the first-to our knowledge-method for noninvasive visualization of p53 in tumor tissue invivo, using SPECT, in 3 different models of cancer. Methods: Anti-p53 monoclonal antibodies were conjugated to the cell-penetrating transactivator of transcription (TAT) peptide and a metal ion chelator and then radiolabeled with 111In to allow SPECT imaging. 111In-anti-p53-TAT conjugates were retained longer in cells overexpressing p53-specific than non-p53-specific 111In-mIgG (mouse IgG from murine plasma)-TAT controls, but not in null p53 cells. Results: In vivo SPECT imaging showed enhanced uptake of 111In-anti-p53-TAT, versus 111In-mIgG-TAT, in high-expression p53R175H and medium-expression wild-type p53 but not in null p53 tumor xenografts. The results were confirmed in mice bearing genetically engineered KPC mouse-derived pancreatic ductal adenocarcinoma tumors. Imaging with 111In-anti-p53-TAT was possible in KPC mice bearing spontaneous p53R172H pancreatic ductal adenocarcinoma tumors. Conclusion: We demonstrate the feasibility of noninvasive invivo molecular imaging of p53 in tumor tissue using a radiolabeled TAT-modified monoclonal antibody.

Myristica fragrans Houtt. methanol extract as a promising treatment for Cryptosporidium parvum infection in experimentally immunosuppressed and immunocompetent mice.

Cryptosporidiosis is a major waterborne disease affecting ruminants and humans worldwide. It causes diarrhea and neonatal mortality in buffalo calves, and watery diarrhea and mortality in children and immunodeficient patients. This study aimed to investigate the efficacy of Myristica fragrans methanolic extract in treatment of C. parvum infection in comparison with nitazoxanide (NZX) (a Food and Drug Administration-approved drug control) in immunosuppressed and immunocompetent mice. One hundred laboratory-bred male Swiss albino mice were equally divided into immunocompetent and immunosuppressed groups. Each group was further divided into five subgroups: (1) non-infected and non-treated control, (2) infected and non-treated control (infected with Cryptosporidium parvum oocysts 3 × 103), (3) NZX-treated (100 mg/kg, 200 μL/mouse), (4) M. fragrans Houtt. methanol extract-treated (500 mg/kg), and (5) combination-treated (NZX + M. fragrans extract). Number of oocysts/g of feces, serum immunoglobulin (Ig) G level, and interferon (IFN)-γ, and interleukin (IL)-4 levels were used to evaluate the therapeutic effect. C. parvum oocyst shedding in stool samples was significantly decreased in all treatment groups, with 79.7%, 81.2 %, and 85.5 % reduction in immunocompetent mice treated with NZX, M. fragrans, and their combination, respectively. In immunosuppressed mice, oocyst shedding was reduced by 77.7%, 80.5 %, and 83.7 % upon NZX, M. fragrans, and their combination treatments, respectively. The serum IgG level was lowest in mice treated with a mixture of M. fragrans and NZX, followed by those treated with NZX, and was highest in mice treated with M. fragrans alone. Regarding cytokine levels, all groups treated with M. fragrans had low levels of IFN-γ and IL4 on day 21 post-infection. Collectively, the treatment of cryptosporidiosis with M. fragrans extract was successful in mice, as demonstrated by the measured parameters. M. fragrans reduced C. parvum oocyst shedding and serum IgG, IFN-γ, and IL-4 levels in immunocompetent and immunosuppressed mice.

Alterations in immunized antigens of Anisakis pegreffii by ampicillin-induced gut microbiome changes in mice.

The gut microbiome plays an essential role in host immune responses, including allergic reactions. However, commensal gut microbiota is extremely sensitive to antibiotics and excessive usage can cause microbial dysbiosis. Herein, we investigated how changes in the gut microbiome induced by ampicillin affected the production of IgG1 and IgG2a antibodies in mice subsequently exposed to Anisakis pegreffii antigens. Ampicillin treatment caused a notable change in the gut microbiome as shown by changes in both alpha and beta diversity indexes. In a 1-dimensional immunoblot using Anisakis-specific anti-mouse IgG1, a 56-kDa band corresponding to an unnamed Anisakis protein was detected using mass spectrometry analysis only in ampicillin-treated mice. In the Anisakis-specific anti-mouse IgG2a-probed immunoblot, a 70-kDa band corresponding to heat shock protein 70 (HSP70) was only detected in ampicillin-treated and Anisakis-immunized mice. A 2-dimensional immunoblot against Anisakis extract with immunized mouse sera demonstrated altered spot patterns in both groups. Our results showed that ampicillin treatment altered the gut microbiome composition in mice, changing the immunization response to antigens from A. pegreffii. This research could serve as a basis for developing vaccines or allergy immunotherapies against parasitic infections.

Immobilizing antibody biorecognition layers on Au–TiO2 thin films: direct (physisorption) vs. DSP-crosslinking (chemisorption) surface functionalization

The immobilization design strategy plays an important role in biosensor development and its sensing performance. Both adsorption (physisorption) and cross-linker functionalization (chemisorption) are common approaches for immobilizing a bioreceptor layer. In this work, these two approaches were studied and compared, envisaging a functional and strongly attached bioreceptor layer onto sputtered Au–TiO2 thin films. DSP cross-linker (Lomant’s reagent) was used in the thin film’s functionalization, and the effect of different concentrations on the development of an adhesion layer was investigated. Surface morphology analysis of functionalized thin films suggested the development of uniformly coated self-assembled layers. However, DSP islands with a fractal structure were found for a concentration of 4 mg ml−1. Infrared spectroscopy confirmed the cross-linker functionalization at the thin film’s surface. Confocal microscopy of immobilized fluorescent antibodies revealed that DSP islands improve the chemical surface area available for bioreceptor immobilization. Moreover, an immunoassay using mouse IgG interaction with fluorescent anti-mouse IgG (Fab specific), working as capture and detection antibody, respectively, showed that DSP functionalization favors antibodies orientation and adhesion strength to the surface, when compared to physisorption.

Structural Elucidation and Anti-Tumor Activity of a Polysaccharide (CP2-S) from Cordyceps militaris Fruit Bodies.

A polysaccharide (CP2-S), consisting of glucose with a weight average molecular weight of 5.9 × 106, was purified from the fruit bodies of Cordyceps militaris. In this work, the corresponding structure and anti-tumor activity in vivo were investigated. Methylation and NMR analysis revealed that CP2-S was composed of a →4)-α-D-Glcp-(1→ backbone with partial substitution occurring at O-6 by T-linked α-D-Glcp in every ten residues, which has not been reported in previous reports. In vivo anti-tumor experiments showed that CP2-S could inhibit the growth of Lewis lung carcinoma in mice. Tumor inhibition rates were 17.8%, 24.5%, and 29.5% at dosages of 12.5, 50, and 100 mg/kg/d, respectively. Compared with the cisplatin group, mice treated with CP2-S exhibited a significant increase in spleen index (increased 22.7-42.4%) and thymus index (increased 47.7-36.8%). Additionally, serum levels of IgM and IgG in tumor-bearing mice increased by approximately 6.11~10.75-folds and 1.31~1.38-folds, respectively. These findings prove that CP2-S significantly inhibited the growth of Lewis lung carcinoma through immune-enhancing activity in mice.

Brain Glucose Metabolism as a Readout of the Central Nervous System Impact of Cigarette Smoke Exposure and Withdrawal and the Effects of NFL-101, as an Immune-Based Drug Candidate for Smoking Cessation Therapy.

Neuroimaging biomarkers are needed to investigate the impact of smoking withdrawal on brain function. NFL-101 is a denicotinized aqueous extract of tobacco leaves currently investigated as an immune-based smoking cessation therapy in humans. However, the immune response to NFL-101 and its ability to induce significant changes in brain function remain to be demonstrated. Brain glucose metabolism was investigated using [18F]fluoro-deoxy-glucose ([18F]FDG) PET imaging in a mouse model of cigarette smoke exposure (CSE, 4-week whole-body inhalation, twice daily). Compared with control animals, the relative uptake of [18F]FDG in CSE mice was decreased in the thalamus and brain stem (p < 0.001, n = 14 per group) and increased in the hippocampus, cortex, cerebellum, and olfactory bulb (p < 0.001). NFL-101 induced a humoral immune response (specific IgGs) in mice and activated human natural-killer lymphocytes in vitro. In CSE mice, but not in control mice, single-dose NFL-101 significantly increased [18F]FDG uptake in the thalamus (p < 0.01), thus restoring normal brain glucose metabolism after 2-day withdrawal in this nicotinic receptor-rich region. In tobacco research, [18F]FDG PET imaging provides a quantitative method to evaluate changes in the brain function associated with the withdrawal phase. This method also showed the CNS effects of NFL-101, with translational perspectives for future clinical evaluation in smokers.

Structure-Activity Relationships toward the Identification of a High-Potency Selective Human Toll-like Receptor-7 Agonist.

Toll-like receptor (TLR)-7 agonists are immunostimulatory vaccine adjuvants. A systematic structure-activity relationship (SAR) study of TLR7-active 1-benzyl-2-butyl-1H-imidazo[4,5-c]quinolin-4-amine led to the identification of a potent hTLR7-specific p-hydroxymethyl IMDQ 23 with an EC50 value of 0.22 μM. The SAR investigation also resulted in the identification of TLR7 selective carboxamide 12 with EC50 values of 0.32 μM for hTLR7 and 18.25 μM for hTLR8. In the vaccination study, TLR7-specific compound 23 alone or combined with alum (aluminum hydroxide wet gel) showed adjuvant activity for a spike protein immunogen in mice, with enhanced anti-spike antibody production. Interestingly, the adjuvant system comprising carboxamide 12 and alum showed prominent adjuvant activity with high levels of IgG1, IgG2b, and IgG2c in immunized mice, confirming a balanced Th1/Th2 response. In the absence of any apparent toxicity, the TLR7 selective agonists in combination with alum may make a suitable vaccine adjuvant.

A TLR4 ligand-based adjuvant for promoting the immunogenicity of typhoid subunit vaccines.

None of the typhoid Vi Polysaccharide (ViPS) subunit vaccines incorporate adjuvants, and the immunogenicity of ViPS vaccines (e.g. Typbar TCV® and Typhim Vi®) is in part due to associated TLR4 ligands such as endotoxin present in these vaccines. Since endotoxin content in vaccines is variable and kept very low due to inherent toxicity, it was hypothesized that incorporating a defined amount of a non-toxic TLR4-ligand such as monophosphoryl lipid A in ViPS vaccines would improve their immunogenicity. To test this hypothesis, a monophosphoryl lipid A-based adjuvant formulation named Turbo was developed. Admixing Turbo with Typbar TCV® (ViPS-conjugated to tetanus toxoid) increased the levels of anti-ViPS IgM, IgG1, IgG2b, IgG2a/c, and IgG3 in inbred and outbred mice. In infant mice, a single immunization with Turbo adjuvanted Typbar TCV® resulted in a significantly increased and durable IgG response and improved the control of bacterial burden compared to mice immunized without Turbo. Similarly, when adjuvanted with Turbo, the antibody response and control of bacteremia were also improved in mice immunized with Typhim Vi®, an unconjugated vaccine. The immunogenicity of unconjugated ViPS is inefficient in young mice and is lost in adult mice when immunostimulatory ligands in ViPS are removed. Nevertheless, when adjuvanted with Turbo, poorly immunogenic ViPS induced a robust IgG response in young and adult mice, and this was observed even under antigen-limiting conditions. These data suggest that incorporation of Turbo as an adjuvant will make typhoid vaccines more immunogenic regardless of their intrinsic immunogenicity or conjugation status and maximize the efficacy across all ages.

A Simplified Workflow for Flow Cytometric Analysis of Extracellular Vesicles on the Invitrogen™ Attune™ NxT Flow Cytometer

Abstract Extracellular vesicles (EV) are miniscule particles composed of a bilipid membrane that are released by all cells. In recent years, it has become clear that EV play an important role in cell-cell communication by shuttling their cargo of proteins, lipids, and nucleic acids. As their content can be indicative of the health of their cell of origin and ability to deliver functional biomolecules, EV have become an increasingly popular topic of research for their diagnostic and therapeutic potential. EV vary in size, surface markers, and content. Their heterogenous nature introduces challenges for analysis when using technologies that were developed for cells. In flow cytometry, EV have a lower refractive index and paucity of epitopes comparative to cells, which hampers detection. In addition, few commercially available antibodies have been specifically validated for EV flow. This combined with the need for tedious isolation processes and a limited range of instruments capable of small particle detection can make EV flow cytometry a daunting endeavor. Despite this, flow cytometry holds promise as an accessible approach to analyze EV. Here, we present a streamlined protocol of EV characterization by flow cytometry in which we adapted the Invitrogen™ CELLection™ Pan Mouse IgG Kit for EV capture and staining and optimized the Invitrogen™ Attune™ NxT Flow Cytometer for small particle resolution to validate monoclonal antibodies targeting EV from human plasma. For research use only.