SARS-CoV-2 mRNA Vaccine Elicits Sustained T Cell Responses Against the Omicron Variant in Adolescents.

Vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been acknowledged as an effective mean of preventing infection and hospitalization. However, the emergence of highly transmissible SARS-CoV-2 variants of concern (VOCs) has led to substantial increase in infections among children and adolescents. Vaccine-induced immunity and longevity have not been well defined in this population. Therefore, we aimed to analyze humoral and cellular immune responses against ancestral and SARS-CoV-2 variants after two shots of the BNT162b2 vaccine in healthy adolescents. Although vaccination induced a robust increase of spike-specific binding Abs and neutralizing Abs against the ancestral and SARS-CoV-2 variants, the neutralizing activity against the Omicron variant was significantly low. On the contrary, vaccine-induced memory CD4+ T cells exhibited substantial responses against both ancestral and Omicron spike proteins. Notably, CD4+ T cell responses against both ancestral and Omicron strains were preserved at 3 months after two shots of the BNT162b2 vaccine without waning. Polyfunctionality of vaccine-induced memory T cells was also preserved in response to Omicron spike protein. The present findings characterize the protective immunity of vaccination for adolescents in the era of continuous emergence of variants/subvariants.

Humoral Immune Response of Heterologous ChAdOx1 nCoV-19 and mRNA-1273 Prime-Boost Vaccination against SARS-CoV-2 Variants in Korea.

The immunogenicity of a heterologous vaccination regimen consisting of ChAdOx1 nCoV-19 (a chimpanzee adenovirus-vectored vaccine) followed by mRNA-1273 (a lipid-nanoparticle-encapsulated mRNA-based vaccine) against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), specifically the omicron variant (B.1.1.529), is poorly studied. The aim of this study was to evaluate the neutralizing antibody activity and immunogenicity of heterologous ChAdOx1 nCoV-19 and mRNA-1273 prime-boost vaccination against wild-type (BetaCoV/Korea/KCDC03/2020), alpha, beta, gamma, delta, and omicron variants of SARS-CoV-2 in Korea. A 50% neutralizing dilution (ND50) titer was determined in serum samples using the plaque reduction neutralization test. Antibody titer decreased significantly at 3 months compared with that at 2 weeks after the 2nd dose. On comparing the ND50 titers for the above-mentioned variants of concerns, it was observed that the ND50 titer for the omicron variant was the lowest. This study provides insights into cross-vaccination effects and can be useful for further vaccination strategies in Korea.

Population Pharmacokinetic Modelling and Simulation to Determine the Optimal Dose of Nanoparticulated Sorafenib to the Reference Sorafenib.

Sorafenib, an oral multikinase inhibitor, exhibits a highly variable absorption profile due to enterohepatic reabsorption and poor solubility. SYO-1644 improved the solubility of sorafenib by nanoparticulation technology leading to enhanced bioavailability. To evaluate the pharmacokinetically equivalent dose of SYO-1644 to the reference Nexavar® 200 mg, a randomized, open-label, replicated two-period study was conducted in healthy volunteers. A total of 32 subjects orally received a single dose of the following assigned treatment under a fasted state in the first period and repeated once more in the second period with a two-week washout: SYO-1644 100, 150 and 200 mg and Nexavar® 200 mg. Pharmacokinetic (PK) samples were collected up to 168 h post-dose. The PK profile was evaluated by both non-compartmental analysis and population PK method. With the final model, 2 × 2 crossover trial scenarios with Nexavar® 200 mg and each dose of SYO-1644 ranging from 100 to 150 mg were repeated 500 times by Monte Carlo simulation, and the proportion of bioequivalence achievement was assessed. Transit absorption compartments, followed by a one-compartment model with first-order elimination and enterohepatic reabsorption components were selected as the final model. The simulation results demonstrated that the SYO-1644 dose between 120 and 125 mg could yielded the highest proportion of bioequivalence.

Development of sorafenib loaded nanoparticles to improve oral bioavailability using a quality by design approach.

Sorafenib, a potent anticancer drug, has low absorption in the gastrointestinal tract due to its poor aqueous solubility. The main purpose of this investigation was to design sorafenib nanoparticle using a newly developed technique, nanoparticulation using fat and supercritical fluid (NUFS™) to improve the absorption of sorafenib. The quality by design (QbD) tool was adopted to define the optimal formulation variables: hydroxypropyl methyl cellulose (HPMC), polyvinyl pyrrolidone K30 (PVP), and poloxamer. The studied response variables were particle size of nanoparticle, dissolution (5, 60, and 180 min), drug concentration time profile of nanoparticle formulations, and maximum drug concentration. The result of particle size revealed that an increase in concentration of poloxamer and HPMC decreased the particle size of nanoparticles (p < 0.05). Likewise, the concentration of drug release at different time point (5, 60, and 180 min) showed HPMC and poloxamer had positive effects on drug dissolution while PVP had negative effects on it. The design space was built in accordance with the particle size of nanoparticle (target < 500 nm) and dissolution of sorafenib (target > 7 µm/mL), following failure probability analysis using Monte Carlo simulations. In vivo pharmacokinetics studies in beagle dogs demonstrated that optimized formulation of sorafenib (F3 and F4 tablets) exhibited higher blood drug profiles indicating better absorption compared to the reference tablet (Nexavar®). In conclusion, this study showed the importance of systematic formulation design for understanding the effect of formulation variables on the characteristics of nanoparticles of the poorly soluble drug.

Single-Dose Comparative Pharmacokinetics of Two Formulations of Lenalidomide 25 mg in Healthy Subjects: A Randomized Crossover Study.

BACKGROUND: Lenalidomide is used for the treatment of multiple myeloma in combination with dexamethasone. The purpose of this study was to compare the pharmacokinetics (PKs) and assess the bioequivalence of two formulations of lenalidomide 25 mg: Lenalid® 25 mg tablet (test formulation) and Revlimid® 25 mg capsule (reference formulation). METHODS: A randomized, single-dose, two-treatment, two-period, two-sequence crossover study was conducted in 42 healthy subjects. All subjects were randomly assigned to one of the two sequences, and they received a single dose of test or reference formulation in the first period and the alternative formulation during the next period under fasting conditions. Serial blood samples for PK evaluation were collected up to 24 h post-dose and the PK parameters were estimated by non-compartmental methods. Throughout the study, tolerability was assessed on the basis of adverse events, vital signs, and clinical laboratory tests. RESULTS: The test formulation showed similar PK profiles to those of the reference formulation. The geometric mean ratio and 90% confidence interval (CI) of the test formulation to the reference formulation for maximum plasma concentration (Cmax) was 0.9995 (0.9250-1.0799) and the corresponding value for the area under the concentration-time curve from time zero to time of last quantifiable concentration (AUCt) was 0.9648 (0.9451-0.9850). Both CIs were within the conventional bioequivalence range of 0.8-1.25. The tolerability profile was not significantly different between the two formulations. CONCLUSION: This study found that the PKs of the two formulations of lenalidomide 25 mg were similar and the test formulation met the regulatory criteria for assuming bioequivalence with the reference formulation. FUNDING: Samyang Biopharmaceutical Corp.

Biodegradation of perfluorooctanesulfonate (PFOS) as an emerging contaminant.

Perfluorooctanesulfonate (PFOS) is a compound of global concern because of its persistence and bioaccumulation in the environment. Nevertheless, little is known of the potential for PFOS biodegradation, even though the importance of characterizing the function and activity of microbial populations detected in the environment has been discussed. This study focused on the biodegradation of PFOS by a specific microorganism. Through this study, we have identified the aerobic microorganism for the specific decomposition of PFOS from wastewater treatment sludge, as a well-known sink for environmental PFOS. This species was Pseudomonas aeruginosa strain HJ4 with a 99% similarity, a mesophilic rod type bacteria (30-37°C). A pH range of 7-9 was determined to be optimal for the growth of strain HJ4. In this study approximately 67% over a range of concentrations (1400-1800µgL(-)(1)) for PFOS was biologically decomposed by P. aeruginosa after 48h incubation. This result is reported here for the first time, which strongly pertains to the efficient biodegradation of PFOS. Therefore, our study is considered a major advancement in sustainable PFOS treatment.

Expression of functional human transferrin in stably transfected Drosophila S2 cells.

Human transferrin (hTf) is a serum glycoprotein involved in Fe3+ transport. Here, a plasmid encoding the hTf gene fused with a hexahistidine (His6) epitope tag under Drosophila metallothionein promoter (pMT) was stably transfected into Drosophila melanogaster S2 cells as a nonlytic plasmid-based system. Following 3 days of copper sulfate induction, transfected S2 cells were found to secrete hTf into serum-free culture medium at a competitively high expression level of 40.8 microg/mL, producing 6.8 microg/mL/day in a 150-mL spinner flask culture. Purification of secreted recombinant hTf using immobilized metal affinity chromatography (IMAC) yielded 95.5% pure recombinant hTf with a recovery of 32%. According to MALDI-TOF mass spectrometry analysis, purified S2 cell-derived His6-tagged recombinant hTf had a molecular weight (76.4 kDa) smaller than that of native apo-hTf (78.0 kDa). 2-Dimensional gel electrophoresis patterns showed recombinant hTf had a simpler and less acidic profile compared to that of native hTf. These data suggest recombinant hTf was incompletely (noncomplex) glycosylated and lacked sialic acids on N-glycans. However, this difference in N-glycan structure compared to native hTf had no effect on the iron-binding activity of recombinant hTf. The present data show that a plasmid-based stable transfection S2 cell system can be successfully employed as an alternative for producing secreted functional recombinant hTf.

Quantitative monitoring for secreted production of human interleukin-2 in stable insect Drosophila S2 cells using a green fluorescent protein fusion partner.

Human interleukin-2 (hIL-2) production in Escherichia coli and insect cell/baculovirus expression systems can be inefficient. Here we investigated secreted production of hIL-2 fused with green fluorescent protein (GFP) as a versatile fusion partner in optimized stably transfected insect Drosophila melanogaster S2 cells. This nonlytic S2 insect cell expression system employs a plasmid vector and allows for secretion of functional human proteins. We report that, following stable transfection and induction, S2 cells secreted hIL-2 as a fusion protein (approximately 2.3 microg/mL yield), with a secretion efficiency of approximately 90%. Regression analysis indicated a single linear relationship existed between GFP fluorescence and hIL-2 mass in both whole cell and secreted medium samples, indicating that in vivo monitoring and quantification of target foreign protein expression and even secretion is possible using this system. The simple comparative measurement of GFP fluorescence also allowed monitoring of secretion efficiency during periods of high GFP/hIL-2 expression.