Physico-Chemical Properties of CdTe/Glutathione Quantum Dots Obtained by Microwave Irradiation for Use in Monoclonal Antibody and Biomarker Testing.

In this report, we present the results on the physicochemical characterization of cadmium telluride quantum dots (QDs) stabilized with glutathione and prepared by optimizing the synthesis conditions. An excellent control of emissions and the composition of the nanocrystal surface for its potential application in monoclonal antibody and biomarker testing was achieved. Two samples (QDYellow, QDOrange, corresponding to their emission colors) were analyzed by dynamic light scattering (DLS), and their hydrodynamic sizes were 6.7 nm and 19.4 nm, respectively. Optical characterization by UV-vis absorbance spectroscopy showed excitonic peaks at 517 nm and 554 nm. Photoluminescence spectroscopy indicated that the samples have a maximum intensity emission at 570 and 606 nm, respectively, within the visible range from yellow to orange. Infrared spectroscopy showed vibrational modes corresponding to the functional groups OH-C-H, C-N, C=C, C-O, C-OH, and COOH, which allows for the formation of functionalized QDs for the manufacture of biomarkers. In addition, the hydrodynamic radius, zeta potential, and approximate molecular weight were determined by dynamic light scattering (DLS), electrophoretic light scattering (ELS), and static light scattering (SLS) techniques. Size dispersion and the structure of nanoparticles was obtained by Transmission Electron Microscopy (TEM) and by X-ray diffraction. In the same way, we calculated the concentration of Cd2+ ions expressed in mg/L by using the Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-OES). In addition to the characterization of the nanoparticles, the labeling of murine myeloid cells was carried out with both samples of quantum dots, where it was demonstrated that quantum dots can diffuse into these cells and connect mostly with the cell nucleus.

Safety and immunogenicity of anti-SARS CoV-2 vaccine SOBERANA 02 in homologous or heterologous scheme: Open label phase I and phase IIa clinical trials.

BACKGROUND: SOBERANA 02 is a COVID-19 vaccine based on SARS-CoV-2 recombinant RBD conjugated to tetanus toxoid (TT). SOBERANA Plus antigen is dimeric-RBD. Here we report safety and immunogenicity from phase I and IIa clinical trials using two-doses of SOBERANA 02 and three-doses (homologous) or heterologous (with SOBERANA Plus) protocols. METHOD: We performed an open-label, sequential and adaptive phase I to evaluate safety and explore the immunogenicity of SOBERANA 02 in two formulations (15 or 25 µg RBD-conjugated to 20 µg of TT) in 40 subjects, 19-59-years-old. Phase IIa was open-label including 100 volunteers 19-80-years, receiving two doses of SOBERANA 02-25 µg. In both trials, half of volunteers were selected to receive a third dose of the corresponding SOBERANA 02 and half received a heterologous dose of SOBERANA Plus. Primary outcome was safety. The secondary outcome was immunogenicity evaluated by anti-RBD IgG ELISA, molecular neutralization of RBD:hACE2 interaction, live-virus-neutralization and specific T-cells response. RESULTS: The most frequent adverse event (AE) was local pain, other AEs had frequencies ≤ 5%. No serious related-AEs were reported. Phase IIa confirmed the safety in 60 to 80-years-old subjects. In phase-I SOBERANA 02-25 µg elicited higher immune response than SOBERANA 02-15 µg and progressed to phase IIa. Phase IIa results confirmed the immunogenicity of SOBERANA 02-25 µg even in 60-80-years. Two doses of SOBERANA02-25 µg elicited an immune response similar to that of the Cuban Convalescent Serum Panel and it was higher after the homologous and heterologous third doses. The heterologous scheme showed a higher immunological response. Anti-RBD IgG neutralized the delta variant in molecular assay, with a 2.5-fold reduction compared to D614G neutralization. CONCLUSIONS: SOBERANA 02 was safe and immunogenic in persons aged 19-80 years, eliciting neutralizing antibodies and specific T-cell response. Highest immune responses were obtained in the heterologous three doses protocol. TRIAL REGISTRY: https://rpcec.sld.cu/trials/RPCEC00000340, https://rpcec.sld.cu/trials/RPCEC00000347.

An efficient synthetic route to O-(2-O-benzyl-3,4-di-O-acetyl-α/ß-l-fucopyranosyl)-trichloroacetimidate.

An efficient synthetic route to prepare O-(2-O-benzyl-3,4-di-O-acetyl-α/ß-l-fucopyranosyl)-trichloroacetimidate from l-fucose was developed by introducing the thiophenyl group at the anomeric center and the benzylidene functional group to protect the 3 and 4 positions. Although three approaches were considered, the best result was obtained when, after the 2-hydroxyl benzylation, both protective groups were simultaneously removed by using acetic anhydride and perchloric acid supported on silica as catalyst. Selective deacetylation of the obtained tri-O-acetate followed by the reaction of the resultant hemiacetal with trichloroacetonitrile and DBU afforded the trichloroacetimidate with an overall yield of 56% from the l-fucose.

Activación del polisacárido capsular de Streptococcus pneumoniae serotipo 23F para la obtención de vacunas conjugadas / Activation of the capsular polysaccharide serotype 23F of Streptococcus pneumoniae to obtain conjugate vaccine

En la actualidad, las vacunas conjugadas constituyen un gran hito en el desarrollo de fármacos que protegen contra las enfermedades infecciosas. Estas vacunas no solo disminuyen drásticamente la mortalidad y morbilidad de diferentes enfermedades causadas por bacterias en la población infantil; sino que también repercuten sobre la población no vacunada. Las vacunas conjugadas se basan en establecer una unión covalente entre un polisacárido y una proteína portadora para lo cual existen diferentes procedimientos químicos. Todos los procedimientos de conjugación requieren la presencia de grupos reactivos complementarios que muchas veces son generados en ambas macromoléculas. Este trabajo se enfoca en el estudio de la reacción de fragmentación y de la oxidación peryódica sobre el polisacárido capsular serotipo 23F de Streptococcus pneumoniae para su uso como antígeno vacunal. Se estableció la fragmentación del polisacárido mediante hidrólisis con ácido acético y trifluoroácetico. En el caso de la reacción de oxidación se encontró que la cantidad de moles de peryodato de sodio y la temperatura influyen de manera directamente proporcional sobre la generación de grupos carbonilos. Adicionalmente se demostró que el sustituyente glicerol-fosfatos presente en la estructura del serotipo 23F es relevante para conservar la antigenicidad. El procedimiento descrito permite obtener conjugados inmunogénicos a partir del polisacárido capsular de Streptococcus pneumoniae serotipo 23F en el modelo de conejo(AU)

Nowadays conjugate vaccines are a major milestone in the development of drugs against infectious diseases. These vaccines drastically reduce mortality and morbidity from different diseases caused by bacteria in children; but also impact on non-vaccinated population. Conjugate vaccines are based on a covalent bond between a polysaccharide and a carrier protein for which there are different chemical procedures. All conjugate procedures require the presence of additional reactive groups that often are generated in both macromolecules. This work focus on the study of the fragmentation reaction and peryodic oxidation on the capsular polysaccharide serotype 23F Streptococcus pneumoniae for use as a vaccine antigen. It was possible to establish the fragmentation reaction of the polysaccharide by hydrolysis with acetic and trifluoroacetic acid. Directly proportional ratio was found between numbers of moles of sodium periodate and temperature on the oxidation reactions. In addition the glycerol-phosphate substituent was found as important motif to preserve the antigenicity. The procedure allows immunogenic conjugate from capsular polysaccharide serotype 23F of Streptococcus pneumoniae in rabbit models(AU)

Activación del polisacárido capsular de Streptococcus pneumoniae serotipo 23F para la obtención de vacunas conjugadas / Activation of the capsular polysaccharide serotype 23F of Streptococcus pneumoniae to obtain conjugate vaccine

En la actualidad, las vacunas conjugadas constituyen un gran hito en el desarrollo de fármacos que protegen contra las enfermedades infecciosas. Estas vacunas no solo disminuyen drásticamente la mortalidad y morbilidad de diferentes enfermedades causadas por bacterias en la población infantil; sino que también repercuten sobre la población no vacunada. Las vacunas conjugadas se basan en establecer una unión covalente entre un polisacárido y una proteína portadora para lo cual existen diferentes procedimientos químicos. Todos los procedimientos de conjugación requieren la presencia de grupos reactivos complementarios que muchas veces son generados en ambas macromoléculas. Este trabajo se enfoca en el estudio de la reacción de fragmentación y de la oxidación peryódica sobre el polisacárido capsular serotipo 23F de Streptococcus pneumoniae para su uso como antígeno vacunal. Se estableció la fragmentación del polisacárido mediante hidrólisis con ácido acético y trifluoroácetico. En el caso de la reacción de oxidación se encontró que la cantidad de moles de peryodato de sodio y la temperatura influyen de manera directamente proporcional sobre la generación de grupos carbonilos. Adicionalmente se demostró que el sustituyente glicerol-fosfatos presente en la estructura del serotipo 23F es relevante para conservar la antigenicidad. El procedimiento descrito permite obtener conjugados inmunogénicos a partir del polisacárido capsular de Streptococcus pneumoniae serotipo 23F en el modelo de conejos(AU)

Nowadays conjugate vaccines are a major milestone in the development of drugs against infectious diseases. These vaccines drastically reduce mortality and morbidity from different diseases caused by bacteria in children; but also impact on non-vaccinated population. Conjugate vaccines are based on a covalent bond between a polysaccharide and a carrier protein for which there are different chemical procedures. All conjugate procedures require the presence of additional reactive groups that often are generated in both macromolecules. This work focus on the study of the fragmentation reaction and peryodic oxidation on the capsular polysaccharide serotype 23F Streptococcus pneumoniae for use as a vaccine antigen. It was possible to establish the fragmentation reaction of the polysaccharide by hydrolysis with acetic and trifluoroacetic acid. Directly proportional ratio was found between numbers of moles of sodium periodate and temperature on the oxidation reactions. In addition the glycerol-phosphate substituent was found as important motif to preserve the antigenicity. The procedure allows immunogenic conjugate from capsular polysaccharide serotype 23F of Streptococcus pneumoniae in rabbit models(AU)

Quantitative proton magnetic resonance determination of N,N-dimethylformamide in one intermediate of the Quimi-Hib vaccine.

Quimi-Hib is a conjugate vaccine against Haemophilus influenza type b (Hib) where the Hib antigen is the only one produced by chemical synthesis. NMR has become the alternative of choice for the identity of intermediates during the chemical synthesis of Hib antigen. We explore a rapid quantitative proton magnetic resonance (qHNMR) assay for the determination of N,N-dimethylformamide (DMF) as a residual in one of the critical intermediates. The proposed assay has been shown to be accurate, precise for intermediate precision conditions (relative standard deviation <3% for spectrometer-to-spectrometer variations), specific (no detected interferences), and rugged (percentage difference <3% for day-to-day and spectrometer-to-spectrometer variations). The quantitative NMR assay can replace the common chromatographic methods for monitoring the DMF contents in one crucial step of the synthetic scheme.

Evaluation and evidence of natural gangliosides with two unsaturated bonds in the ceramide structure obtained by a combination of MALDI-MS and NMR spectroscopy.

Gangliosides are membrane-associated glycosphingolipids. N-Acetyl GM3 and N-glycolyl GM3 are two tumor-associated antigens expressed in cancer tissues such as melanoma and mammalian cancer. In order to use these antigens in GM3-based vaccines for patients with early stage cancer, the synthetic version is recommended to avoid the risk of animal virus transmission from the source. However, the isolation of natural gangliosides is of comparative value for the structural characterization. The structures of N-acetyl and N-glycolyl GM3 extracted from dog and horse erythrocytes were evaluated by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and nuclear magnetic resonance techniques; additionally, the natural N-acetyl ganglioside was compared to a synthetic one. In addition to the main compound with C24:0 fatty acid chain, a minor component with an additional unsaturation in the ceramide chain was detected, in both the dog and the horse gangliosides. This paper shows spectroscopic evidence of the aforementioned compounds.