Development of a Broadly Protective, Self-Adjuvanting Subunit Vaccine to Prevent Infections by Pseudomonas aeruginosa

Infections caused by the opportunistic pathogen Pseudomonas aeruginosa can be difficult to treat due to innate and acquired antibiotic resistance and this is exacerbated by the emergence of multi-drug resistant strains. Unfortunately, no licensed vaccine yet exists to prevent Pseudomonas infections. Here we describe a novel subunit vaccine that targets the P. aeruginosa type III secretion system (T3SS). This vaccine is based on the novel antigen PaF (Pa Fusion), a fusion of the T3SS needle tip protein, PcrV, and the first of two translocator proteins, PopB. Additionally, PaF is made self-adjuvanting by the N-terminal fusion of the A1 subunit of the mucosal adjuvant double-mutant heat-labile enterotoxin (dmLT). Here we show that this triple fusion, designated L-PaF, can activate dendritic cells in vitro and elicits strong IgG and IgA titers in mice when administered intranasally. This self-adjuvanting vaccine expedites the clearance of P. aeruginosa from the lungs of challenged mice while stimulating host expression of IL-17A, which may be important for generating a protective immune response in humans. L-PaF’s protective capacity was recapitulated in a rat pneumonia model, further supporting the efficacy of this novel fusion vaccine

A protein subunit vaccine elicits a balanced immune response that protects against Pseudomonas pulmonary infection

The opportunistic pathogen Pseudomonas aeruginosa (Pa) causes severe nosocomial infections, especially in immunocompromised individuals and the elderly. Increasing drug resistance, the absence of a licensed vaccine and increased hospitalizations due to SARS-CoV-2 have made Pa a major healthcare risk. To address this, we formulated a candidate subunit vaccine against Pa (L-PaF), by fusing the type III secretion system tip and translocator proteins with LTA1 in an oil-in-water emulsion (ME). This was mixed with the TLR4 agonist (BECC438b). Lung mRNA sequencing showed that the formulation activates genes from multiple immunological pathways eliciting a protective Th1-Th17 response following IN immunization. Following infection, however, the immunized mice showed an adaptive response while the PBS-vaccinated mice experienced rapid onset of an inflammatory response. The latter displayed a hypoxic lung environment with high bacterial burden. Finally, the importance of IL-17 and immunoglobulins were demonstrated using knockout mice. These findings suggest a need for a balanced humoral and cellular response to prevent the onset of Pa infection and that our formulation could elicit such a response

Immunogenicity and protective efficacy of nanoparticle formulations of L-SseB against Salmonella infection

Salmonella enterica, a Gram-negative pathogen, has over 2500 serovars that infect a wide range of hosts. In humans, S. enterica causes typhoid or gastroenteritis and is a major public health concern. In this study, SseB (the tip protein of the Salmonella pathogenicity island 2 type III secretion system) was fused with the LTA1 subunit of labile-toxin from enterotoxigenic E. coli to make the self-adjuvanting antigen L-SseB. Two unique nanoparticle formulations were developed to allow multimeric presentation of L-SseB. Mice were vaccinated with these formulations and protective efficacy determined via challenging the mice with S. enterica serovars. The polysaccharide (chitosan) formulation was found to elicit better protection when compared to the squalene nanoemulsion. When the polysaccharide formulation was used to vaccinate rabbits, protection from S. enterica challenge was elicited. In summary, L-SseB in a particulate polysaccharide formulation appears to be an attractive candidate vaccine capable of broad protection against S. enterica

Impact of the TLR4 agonist BECC438 on a novel vaccine formulation against Shigella spp.

Shigellosis (bacillary dysentery) is a severe gastrointestinal infection with a global incidence of 90 million cases annually. Despite the severity of this disease, there is currently no licensed vaccine against shigellosis. Shigella’s primary virulence factor is its type III secretion system (T3SS), which is a specialized nanomachine used to manipulate host cells. A fusion of T3SS injectisome needle tip protein IpaD and translocator protein IpaB, termed DBF, when admixed with the mucosal adjuvant double-mutant labile toxin (dmLT) from enterotoxigenic E. coli was protective using a murine pulmonary model. To facilitate the production of this platform, a recombinant protein that consisted of LTA-1, the active moiety of dmLT, and DBF were genetically fused, resulting in L-DBF, which showed improved protection against Shigella challenge. To extrapolate this protection from mice to humans, we modified the formulation to provide for a multivalent presentation with the addition of an adjuvant approved for use in human vaccines. Here, we show that L-DBF formulated (admix) with a newly developed TLR4 agonist called BECC438 (a detoxified lipid A analog identified as Bacterial Enzymatic Combinatorial Chemistry candidate #438), formulated as an oil-in-water emulsion, has a very high protective efficacy at low antigen doses against lethal Shigella challenge in our mouse model. Optimal protection was observed when this formulation was introduced at a mucosal site (intranasally). When the formulation was then evaluated for the immune response it elicits, protection appeared to correlate with high IFN-γ and IL-17 secretion from mucosal site lymphocytes

Dexamethasone intravitreal implant in previously treated patients with diabetic macular edema : Subgroup analysis of the MEAD study

Background: Dexamethasone intravitreal implant 0.7 mg (DEX 0.7) was approved for treatment of diabetic macular edema (DME) after demonstration of its efficacy and safety in the MEAD registration trials. We performed subgroup analysis of MEAD study results to evaluate the efficacy and safety of DEX 0.7 treatment in patients with previously treated DME. Methods: Three-year, randomized, sham-controlled phase 3 study in patients with DME, best-corrected visual acuity (BCVA) of 34.68 Early Treatment Diabetic Retinopathy Study letters (20/200.20/50 Snellen equivalent), and central retinal thickness (CRT) 65300 \u3bcm measured by time-domain optical coherence tomography. Patients were randomized to 1 of 2 doses of DEX (0.7 mg or 0.35 mg), or to sham procedure, with retreatment no more than every 6 months. The primary endpoint was 6515-letter gain in BCVA at study end. Average change in BCVA and CRT from baseline during the study (area-under-the-curve approach) and adverse events were also evaluated. The present subgroup analysis evaluated outcomes in patients randomized to DEX 0.7 (marketed dose) or sham based on prior treatment for DME at study entry. Results: Baseline characteristics of previously treated DEX 0.7 (n = 247) and sham (n=261) patients were similar. In the previously treated subgroup, mean number of treatments over 3 years was 4.1 for DEX 0.7 and 3.2 for sham, 21.5 % of DEX 0.7 patients versus 11.1 % of sham had 6515-letter BCVA gain from baseline at study end (P = 0.002), mean average BCVA change from baseline was +3.2 letters with DEX 0.7 versus +1.5 letters with sham (P = 0.024), and mean average CRT change from baseline was -126.1 \u3bcm with DEX 0.7 versus -39.0 \u3bcm with sham(P < 0.001). Cataract-related adverse events were reported in 70.3 % of baseline phakic patients in the previously treated DEX 0.7 subgroup; vision gains were restored following cataract surgery. Conclusions: DEX 0.7 significantly improved visual and anatomic outcomes in patients with DME previously treated with laser, intravitreal anti-vascular endothelial growth factor, intravitreal triamcinolone acetonide, or a combination of these therapies. The safety profile of DEX 0.7 in previously treated patients was similar to its safety profile in the total study population

Spectroscopic and laser properties of Er3+ doped fluoro-phosphate glasses as promising candidates for broadband optical fiber lasers and amplifiers

Sem informaçãoDifferent fluoro-phosphate glasses doped with 0.5 mol% Er3+ doped are prepared by melt quenching method. Both structural and spectroscopic properties have been characterized in order to evaluate their potential as both laser source and amplifier materials. Optical absorption measurements are carried out and analyzed through Judd-Ofelt and Mc-Cumber theories where spectroscopic parameters such as intensity parameters Omega(i) (lambda = 2,4,6), transition probabilities, radiative lifetimes, stimulated absorption cross-sections and emission cross-sections at 1.5 mu m have been evaluated for Er3+ doped different fluorophosphate glasses. The various luminescence and gain properties are explained from photoluminescence studies. The decay curve analysis have been done for obtaining the decay time constants of Er3+ excited level I-4(13/2) in all the fluoro-phosphate glasses. The obtained results of each glass matrix are compared with the equivalent parameters for several other host glasses. These fluoro-phosphate glasses are found to be suitable candidates for laser and amplifier applications. (C) 2015 Elsevier Ltd. All rights reserved.Different fluoro-phosphate glasses doped with 0.5 mol% Er3+ doped are prepared by melt quenching method. Both structural and spectroscopic properties have been characterized in order to evaluate their potential as both laser source and amplifier materials. Optical absorption measurements are carried out and analyzed through Judd-Ofelt and Mc-Cumber theories where spectroscopic parameters such as intensity parameters Omega(i) (lambda = 2,4,6), transition probabilities, radiative lifetimes, stimulated absorption cross-sections and emission cross-sections at 1.5 mu m have been evaluated for Er3+ doped different fluorophosphate glasses. The various luminescence and gain properties are explained from photoluminescence studies. The decay curve analysis have been done for obtaining the decay time constants of Er3+ excited level I-4(13/2) in all the fluoro-phosphate glasses. The obtained results of each glass matrix are compared with the equivalent parameters for several other host glasses. These fluoro-phosphate glasses are found to be suitable candidates for laser and amplifier applications.70935944Sem informaçãoSem informaçãoSem informaçãoOne of the authors S. Babu would like to thank University Grants Commission (UGC), New Delhi for the sanction of SRF under Research Fellowship in Sciences for Meritorious Students (RFSMS) scheme

Study of multicomponent fluoro-phosphate based glasses: Ho3+ as a luminescence center

Sem informaçãoThe multicomponent 49.5P(2)O(5)-10AlF(3)-10BaF(2)-10SrF(2)-10PbO-10M (M=Li2O, Na2O, K2O, ZnO and Bi2O3) glasses doped with 0.5 mol% holmium were prepared by melt quenching technique. Their thermal behavior was examined from differential scanning calorimetry (DSC). It is found that bismuth fluorophosphate glass matrix has good thermal stability. Their structures were characterized by the X-ray diffraction with SEM analysis, fourier transform infrared (FTIR), Raman spectroscopy and magic angle spinning (MAS) nuclear magnetic resonance (NMR) techniques. It was found that the phosphate network of these glasses was composed mainly of Q(2) and Q(3) phosphate tetrahedral units. The Judd-Ofelt parameters (J-O) (Omega(2), Omega(4) and Omega(6)) were evaluated from the intensities of the energy levels through optical absorption spectra. The most intense transitions are observed in the visible region of the spectrum. It is observed that the transition I-5(8) -> (5)G(6) is the hypersensitive transition for Ho3+ ion. With these J-O parameters, various radiative properties like the probabilities of radiative transitions, radiative lifetimes and branching ratios have been calculated for different fluoro-phosphate glasses. The luminescence kinetics from excited holmium levels have been studied upon selective excitation through photoluminescence measurements. Holmium produces two visible laser emissions i.e. one is green (F-5(4)(S-5(2)) -> I-5(8)) and another one is red (F-5(5) -> I-5(8)). The lifetimes of these levels have been experimentally determined through decay profile studies. The above results suggest that the prepared bismuth fluorophosphate glass system could be a suitable candidate for using it as a green laser source (F-5(4)(S-5(2)) -> I-5(8)) in the visible region of the spectrum. (C) 2015 Elsevier B.V. All rights reserved.The multicomponent 49.5P(2)O(5)-10AlF(3)-10BaF(2)-10SrF(2)-10PbO-10M (M=Li2O, Na2O, K2O, ZnO and Bi2O3) glasses doped with 0.5 mol% holmium were prepared by melt quenching technique. Their thermal behavior was examined from differential scanning calorimetry (DSC). It is found that bismuth fluorophosphate glass matrix has good thermal stability. Their structures were characterized by the X-ray diffraction with SEM analysis, fourier transform infrared (FTIR), Raman spectroscopy and magic angle spinning (MAS) nuclear magnetic resonance (NMR) techniques. It was found that the phosphate network of these glasses was composed mainly of Q(2) and Q(3) phosphate tetrahedral units. The Judd-Ofelt parameters (J-O) (Omega(2), Omega(4) and Omega(6)) were evaluated from the intensities of the energy levels through optical absorption spectra. The most intense transitions are observed in the visible region of the spectrum. It is observed that the transition I-5(8) -> (5)G(6) is the hypersensitive transition for Ho3+ ion. With these J-O parameters, various radiative properties like the probabilities of radiative transitions, radiative lifetimes and branching ratios have been calculated for different fluoro-phosphate glasses. The luminescence kinetics from excited holmium levels have been studied upon selective excitation through photoluminescence measurements. Holmium produces two visible laser emissions i.e. one is green (F-5(4)(S-5(2)) -> I-5(8)) and another one is red (F-5(5) -> I-5(8)). The lifetimes of these levels have been experimentally determined through decay profile studies. The above results suggest that the prepared bismuth fluorophosphate glass system could be a suitable candidate for using it as a green laser source (F-5(4)(S-5(2)) -> I-5(8)) in the visible region of the spectrum.4792634Sem informaçãoSem informaçãoSem informaçãoOne of the authors S. Babu would like to thank University Grants Commission (UGC), New Delhi for the sanction of Senior Research Fellowship (SRF) under Research Fellowship in Sciences for Meritorious students (RFSMS) scheme. Also thanks to SAIF IISc, Bangalore for providing solid state NMR facilities

Spectroscopic investigations on Ho3+ doped mixed alkali phosphate glasses

Optical absorption and emission properties of Ho3+ doped mixed alkali phosphate glasses of the type 69.5NH4H2PO4. xLi2-CO3.(30-x)K2CO3 and 69.5NH4H2PO4.xNa2CO3.(30-x)K2CO3 (where x = 5, 10, 15, 20 and 25) were studied. Racah (E1, E2,E3), spin–orbit (n4f) and configuration interaction (a, b) parameters are calculated and these values are compared for different x values in the glass matrix. Judd–Ofelt intensity parameters (X2, X4, X6) are calculated for all the Ho3+ doped mixed alkali phosphate glasses. From these parameters and from the spectral profiles of the hypersensitive transition structural studies have obtained. Radiative transition probabilities (A), radiative lifetimes (s), branching ratios (b) and integrated absorption cross-sections (R) are obtained from the intensity parameters. Emission cross-sections (r) are calculated for the two transitions, 5F4, 5S2? 5I8 and 5F5 ?5I8 of Ho3+ in these two mixed alkali phosphate glasses. Optical band gaps (Eopt) for both direct and indirect transitions are reported

Optical absorption and photoluminescence properties of Nd3+ doped mixed alkali phosphate glasses-spectroscopic investigations

Spectroscopic investigations were performed on 68NH4H2PO4·xLi2CO3(30 − x)K2CO3 and 68NH4H2PO4·xNa2CO3(30 − x)K2CO3 (where x = 5, 10, 15, 20 and 25) glasses containing 2 mol% Nd2O3. Various spectroscopic parameters (Racah (E1, E2, E3), spin–orbit (ξ4f) and configuration interaction (α)) are reported. Judd–Ofelt intensity parameters (Ω2, Ω4, Ω6) are calculated for Nd3+ doped two mixed alkali phosphate glass matrices. From the magnitude of Judd–Ofelt parameters, covalency is studied as a function of x in the glass matrix. Using Judd–Ofelt intensity parameters, total radiative transition probabilities (AT), radiative lifetimes (τR), branching ratios (β) and integrated absorption cross sections (Σ) have been computed for certain excited states of Nd3+ in these mixed alkali phosphate glasses. Emission cross sections (σP) are calculated for the two transitions, 4G7/2 → 4I11/2 and 4G7/2 → 4I13/2 of Nd3+ in these mixed alkali phosphate glasses. Optical band gaps (Eopt) for direct and indirect transitions are reported