Disulfide-stabilized trimeric hemagglutinin ectodomains provide enhanced heterologous influenza protection.

Influenza virus infection poses a continual menace to public health. Here, we developed soluble trimeric HA ectodomain vaccines by establishing interprotomer disulfide bonds in the stem region, which effectively preserve the native antigenicity of stem epitopes. The stable trimeric H1 ectodomain proteins exhibited higher thermal stabilities in comparison with unmodified HAs and showed strong binding activities towards a panel of anti-stem cross-reactive antibodies that recognize either interprotomer or intraprotomer epitopes. Negative stain transmission electron microscopy (TEM) analysis revealed the stable trimer architecture of the interprotomer disulfide-stapled WA11#5, NC99#2, and FLD#1 proteins as well as the irregular aggregation of unmodified HA molecules. Immunizations of mice with those trimeric HA ectodomain vaccines formulated with incomplete Freund's adjuvant elicited significantly more potent cross-neutralizing antibody responses and offered broader immuno-protection against lethal infections with heterologous influenza strains compared to unmodified HA proteins. Additionally, the findings of our study indicate that elevated levels of HA stem-specific antibody responses correlate with strengthened cross-protections. Our design strategy has proven effective in trimerizing HA ectodomains derived from both influenza A and B viruses, thereby providing a valuable reference for designing future influenza HA immunogens.

Sequential Immunizations with Influenza Neuraminidase Protein Followed by Peptide Nanoclusters Induce Heterologous Protection.

Enhancing cross-protections against diverse influenza viruses is desired for influenza vaccinations. Neuraminidase (NA)-specific antibody responses have been found to independently correlate with a broader influenza protection spectrum. Here, we report a sequential immunization regimen that includes priming with NA protein followed by boosting with peptide nanoclusters, with which targeted enhancement of antibody responses in BALB/c mice to certain cross-protective B-cell epitopes of NA was achieved. The nanoclusters were fabricated via desolvation with absolute ethanol and were only composed of composite peptides. Unlike KLH conjugates, peptide nanoclusters would not induce influenza-unrelated immunity. We found that the incorporation of a hemagglutinin peptide of H2-d class II restriction into the composite peptides could be beneficial in enhancing the NA peptide-specific antibody response. Of note, boosters with N2 peptide nanoclusters induced stronger serum cross-reactivities to heterologous N2 and even heterosubtypic N7 and N9 than triple immunizations with the prototype recombinant tetrameric (rt) N2. The mouse challenge experiments with HK68 H3N2 also demonstrated the strong effectiveness of the peptide nanocluster boosters in conferring heterologous protection.

Boost immunizations with NA-derived peptide conjugates achieve induction of NA inhibition antibodies and heterologous influenza protections.

Neuraminidase is suggested as an important component for developing a universal influenza vaccine. Targeted induction of neuraminidase-specific broadly protective antibodies by vaccinations is challenging. To overcome this, we rationally select the highly conserved peptides from the consensus amino acid sequence of the globular head domains of neuraminidase. Inspired by the B cell receptor evolution process, a reliable sequential immunization regimen is designed to result in immuno-focusing by steering bulk immune responses to a selected region where broadly protective B lymphocyte epitopes reside. After priming neuraminidase protein-specific antibody responses in C57BL/6 or BALB/c inbred mice strains by immunization or pre-infection, boost immunizations with certain neuraminidase-derived peptide-keyhole limpet hemocyanin conjugates significantly strengthened serum neuraminidase inhibition activities and cross-protections. Overall, this study provides proof of concept for a peptide-based sequential immunization strategy for achieving targeted induction of cross-protective antibody response, which provides references for designing universal vaccines against other highly variable pathogens.

Levels of serum procalcitonin and C-reactive protein for evaluating pulmonary bacterial infection in patients with lupus erythematosus.

The severity of systemic lupus erythematosus (SLE) patients with pulmonary bacterial infection varies widely. We investigated the significance of procalcitonin (PCT) and C-reactive protein (CRP) in evaluating the severity of pulmonary infection in SLE patients. This retrospective study contained a total of 117 patients (107 women and 10 men) with SLE from January 2010 to June 2011. Serum levels of PCT and CRP were measured by enzyme-linked immunosorbent assay. The severity of pulmonary bacterial infection (PBI) was evaluated using the pneumonia severity index (PSI). SLE patients with PBI, particularly those with bacterial isolates, had significantly higher levels of serum PCT and CRP than those without PBI. Serum PCT and CRP were not associated with SLE disease activity, but positively with the values of PSI in active SLE patients with PBI. Serum levels of PCT and CRP may be additional biomarkers in evaluating the severity of PBI in lupus patients.

Pulmonary embolism, deep vein thrombosis and recurrent bone cysts in a patient with hypereosinophilic syndrome.

Herein we present a case of hypereosinophilic syndrome with a unique clinical presentation. A 32-year-old man was admitted because of fever, hemoptysis and chest pain. The main clinical features include hypereosinophilia, deep vein thrombosis, pulmonary embolism, thrombocytopenia and recurrent bone cysts. The plain film of the left foot revealed dissolvent bone destruction. The histological findings of bone cysts include eosinophilic infiltration and tissue necrosis. According to the case history and literature, it is possible that hypereosinophilia itself may be a risk for thrombogenesis and the bone destruction.

[Spectral study of three compounds of tungstosilicic salt with Keggin structure].

Three compounds of tungstosilicic acid and tungstosilicic salt: K3H[SiW(VI)12O40].3H2O(I), (H3O)4[H3SiW(VI)9W(V)3O40].2H2O(II) and [(CH3)4N]4[SiW(VI)12O40].4.5H2O(III), with Keggin structure, have been synthesized. The relationship between their properties and structures was studied by using FTIR, NIR FT-Raman, UV-Vis and flurescence etc. They possess isolated [SiW12O40] cage anion, which combines with cation and water by static electric action and weak hydrogen bond; The study of their FTIR and Raman spectra shows that the vibrational frequencies of the group are related to the structure of the materials. For the compound II, the vibrational frequency of vas(W=Od) decreases as part of W6+ are reduced to W5+, and the charges of anion group affect vas(W-Oc-W), vas(Si-Oa) and delta(Oa-Si-Oa) etc. apparently. In UV-Vis spectra of compound I and II, there are two characteristic peaks at 200 and 260 nm, respectively. The fluorescence spectra of compound I were studied, and showed that the emission peak is at 350, 440, 520 and 675 nm excited by 220, 350 and 440 nm.