CpG 684: an effective adjuvant for the inactivated COVID-19 vaccine in mice.

Aim: This study used CpG 684 as adjuvant of inactivated COVID-19 vaccine to detect a humoral and cellular immune response in mice. Materials & methods: We used 10 and 20 µg CpG 684 as adjuvants of an inactivated COVID-19 vaccine to immunize mice. IgG, IgG1, IgG2a, IgG2b and IgM binding antibodies were detected in serum by ELISA. The IFN-γ cytokine was detected by ELISPOT. Results: CpG 684 improved spike-specific IgG and IgM subtype binding antibodies and increased the neutralizing antibody titer against prototype, Delta and Beta strains. CpG 684 also improved cellular immune response. Conclusion: CpG 684 is an effective adjuvant for inactivated COVID-19 vaccine.

Comparison of the immunogenicity of nasal-spray rVSV vector, adenovirus vector, and inactivated COVID-19-based vaccines in rodent models.

Intranasal (i.n.) vaccines can induce mucosal and systemic immunity against respiratory pathogens. Previously, we demonstrated that the recombinant vesicular stomatitis virus (rVSV)-based COVID-19 vaccine rVSV-SARS-CoV-2, with poor immunogenicity via the intramuscular route (i.m.), is more suitable for i.n. administration in mice and nonhuman primates. Here, we found that the rVSV-SARS-CoV-2 Beta variant was more immunogenic than the wild-type strain and other variants of concern (VOCs) in golden Syrian hamsters. Furthermore, the immune responses elicited by rVSV-based vaccine candidates via the i.n. route were significantly higher than those of two licensed vaccines: the inactivated vaccine KCONVAC delivered via the i.m. route and the adenovirus-based Vaxzevria delivered i.n. or i.m. We next assessed the booster efficacy of rVSV following two i.m. doses of KCONVAC. Twenty-eight days after receiving two i.m. doses of KCONVAC, hamsters were boosted with a third dose of KCONVAC (i.m.), Vaxzevria (i.m. or i.n.), or rVSVs (i.n.). Consistent with other heterologous booster studies, Vaxzevria and rVSV elicited significantly higher humoral immunity than the homogenous KCONVAC. In summary, our results confirmed that two i.n. doses of rVSV-Beta elicited significantly higher humoral immune responses than commercial inactivated and adeno-based COVID vaccines in hamsters. As a heterologous booster dose, rVSV-Beta induced potent, persistent, and broad-spectrum humoral and mucosal neutralizing responses against all VOCs, highlighting its potential to be developed into a nasal-spray vaccine.

A Spike-destructing human antibody effectively neutralizes Omicron-included SARS-CoV-2 variants with therapeutic efficacy.

Neutralizing antibodies (nAbs) are important assets to fight COVID-19, but most existing nAbs lose the activities against Omicron subvariants. Here, we report a human monoclonal antibody (Ab08) isolated from a convalescent patient infected with the prototype strain (Wuhan-Hu-1). Ab08 binds to the receptor-binding domain (RBD) with pico-molar affinity (230 pM), effectively neutralizes SARS-CoV-2 and variants of concern (VOCs) including Alpha, Beta, Gamma, Mu, Omicron BA.1 and BA.2, and to a lesser extent for Delta and Omicron BA.4/BA.5 which bear the L452R mutation. Of medical importance, Ab08 shows therapeutic efficacy in SARS-CoV-2-infected hACE2 mice. X-ray crystallography of the Ab08-RBD complex reveals an antibody footprint largely in the ß-strand core and away from the ACE2-binding motif. Negative staining electron-microscopy suggests a neutralizing mechanism through which Ab08 destructs the Spike trimer. Together, our work identifies a nAb with therapeutic potential for COVID-19.

Erratum: Expression, purification and characterization of Der f 27, a new allergen from dermatophagoides farinae.

[This corrects the article on p. 1260 in vol. 7, PMID: 26328010.].

Characterization and analysis of a cDNA coding for the group 29b (Der f 29b) allergen of Dermatophagoides farinae.

This study aims to acquire a recombinant allergen of Der f 29b by cloning and expression, and to identify its immunogenicity. In this study, the total RNA of D. farinae was extracted, cloned and expressed based on the Der f 29b gene. The molecular characteristics of Der f 29b was analyzed by the procedures of Bioinformatics. The allergenicity of recombinant Der f 29b protein was examined by western-blotting, ELISA, Immune inhibitory assays and skin prick test. The gene of Der f 29b consisted of 495 bases, derived from its nucleic acid sequence and encoded 164 amino acids. Positive responses to r-Der f 29b were shown in 24.3% by means of skin prick testing with 37 DM-allergic patients. The immunoblotting assays demonstrated that serum IgE from allergic patients reacted to r-Der f 29b protein. The IgE reactivity of r-Der f 29b in the serum from r-Der f 29b allergic patients was increased by more than 2 folds compared with healthy subjects. Immune inhibition assays showed that the IgE cross-reactivity was between r-Der f 29b and DME. Bioinformatics analysis predicted four peptides (13-17, 67-71, 104-109 and 147-155) as the B cell epitopes and five peptides (5-14, 16-31, 35-43, 52-63 and 87-97) as the T cell epitopes. Secondary structure prediction of Der f 29b with software PSIPRED identified two α-helices and seven ß-sheets in Der f 29b. In conclusion, Derf 29b protein was identified as a novel subtype of dust mite allergen.

Der f 21, a novel allergen from dermatophagoides farina.

The Dermatophagoides farina (D. farina) allergens are an important factor contributing to allergic disease. To identify new allergens is important for diagnosis and treatment of allergic diseases. In this study, we sought to characterize the biological activity of Der f 21 of D. farina. The recombinant Der f 21 protein was characterized by western-blot, ELISA and Skin prick test using clinic patient's serum.An allergic asthma mouse model was established with the rDer f 21 as a specific antigen. The results showed that the sera from 28.9% in 38 dust mite allergic children displayed positive results in response to rDer f 21, and 42% in 98 dust mite allergic patients displayed positive response in skin prick test. In addition, Immune inhibition assays showed there was IgE cross-reactivity between rDer f 21 and rDer f 5. Moreover, an allergic asthma mouse model was established. Airway hyperresponsiveness, serum specific IgE, IgG1, eosinophil infiltration in the allergic mice, interleukin-4(IL-4) and interferon-γ (INF-γ) from spleen cells were markedly increased in the allergic mice. The results demonstrate that Der f 21 is a novel allergen.

Expression, purification and characterization of Der f 27, a new allergen from dermatophagoides farinae.

The house dust mite (HDM), Dermatophagoidesfarinae (D. farina), is one of the most important indoor allergen sources and a major elicitor of allergic asthma; itscharacterization is important in the diagnosis and immunotherapy of mite allergen-relevant diseases. This study aims to characterize a novel allergen, the D. farinae-derived serpin (Der f 27). In this study, the total RNA of D. farinae was extracted, and the Der f 27 gene was cloned and expressed. The allergenicity of recombinant Der f 27 protein was determined by enzyme-linked immunosorbent assay, and Western-blotting with the sera of asthma patients, and skin prick test (SPT) in allergic human subjects. A r-Der f 27 allergic asthma mouse model was established. The cloned Der f 27 gene has been presented at the Gene Bank with an accession number of KM009995. The IgE levels of r-Der f 27 in the serum from r-Der f 27 SPT positive allergic patients were 3 folds more than healthy subjects. The Der f 27 SPT positive ratewas 42.1% in 19 DM-SPT positive patients. Airway hyperresponsiveness, serum specific IgE, and levels of interleukin-4 in the spleen cell culture supernatant were significantly increased in allergic asthma mice sensitized to r-Der f 27. In conclusion, Der f 27 is a new subtype of house mite allergen.

Characterization of Der f 29, a new allergen from dermatophagoides farinae.

More than 30 allergens have been identified from Dermatophagoides farina (D. farina), which is one of the main species of house dust mites. The mite allergens are an important factor contributing to allergic disease in the world. As the detection and identification of new allergens is critical for the diagnosis or treatment of allergic diseases, we sought to characterize the profilin of D. farina (Der f 29) in this study. The results showed that 21% of allergic patients displayed positive results in skin prick test with recombinant Der f 29 (rDer f 29) as the specific allergen; specific IgE reactivity to rDer f 29 was shown by Western Blot and ELISA. In addition, rDer f 29 induced bone marrow-derived dendritic cells (DC) to produce T cells immunoglobulin domain and mucin domain protein 4 (TIM4). Moreover, an allergic asthma mouse model was established by challenging with rDer f 29. Airway hyperresponsiveness, serum specific IgE, IgG1, eosinophil infiltration in the allergic mice bronchoalveolar lavage fluid, the cytokines interleukin-4 (IL-4) and interferon-γ (INF-γ) from spleen cells were markedly increased; the histology showed severe inflammation in the lung. In conclusion, Der f 29 is identified as a new type of the house dust mite allergen.

Characterization of arginine kinase, anovel allergen of dermatophagoides farinae (Der f 20).

OBJECTIVE: To characterize a novel allergen, the Dermatophagoides farinae-derived arginine kinase (Der f 20). METHODS: The protein of Der f 20 was synthesized by genetic engineering approaches. The allergenicity of Der f 20 was tested by enzyme-linked immunosorbent assay and an airway allergy mouse model. RESULTS: The Der f 20 gene was cloned andpresented in the Gene Bank with an accession number of AAP57094. The Der f 20 is an arginine kinase (AK), whichshowed a close relationship with D. pteronyssinus AK and Aleuroglyphusovatus AK. Western-blot and ELISA studies showed the IgE binding capacity of Der f 20 was 66.7% in the sera from 6 dust mite allergic patients. Immune inhibition assayresults showed the IgE cross-reactivity between Der f 20 and DME (Dust mite extract). Positive responses to Der f 20 were 41.2% as shown by skin prick tests in 17 DME-allergic patients. In vitro experimental results showed that Der f 20 induced Th2 cell differentiation and the expression of T cell Ig mucin domain molecule-4 (TIM4) in DCs. Conclusions; The Der f 20 protein is a novel subtype of thedust mite allergen.

[Therapeutic effect and mechanism of Phoenix roebelenii pollen vaccine for treatment of mice with allergic rhinitis].

OBJECTIVE: To apply Phoenix roebelenii pollen vaccine to murine models of allergic rhinitis and observe the pathological changes of allergic rhinitis in mice, and to study the efficacy and mechanism of the vaccine for the treatment of allergic rhinitis. METHODS: BALB/c mice models of allergic rhinitis were established by intraperitoneal injection, and then treated with immunotherapy of allergen vaccine by subcutaneous injection. The mice were examined for the levels of airway hyperresponsiveness by a noninvasive lung function detector, for the specific antibodies IgE and IgG2a in serum and cytokines by indirect ELISA, and for the pathological changes of ultrastructure of nasal mucosa of the mice by transmission electron microscopy before and after the treatment. RESULTS: After the immunotherapy, nasal symptoms and airway hyperresponsiveness of the mice were relieved. The level of specificity antibody IgG2a in serum was elevated, and IgE dropped significantly. In the culture supernatant of spleen cells, INF-γ and IL-10 levels increased and the production of IL-4 decreased. CONCLUSION: The recombinant profilin of the Phoenix roebelenii pollen as vaccine has a certain therapeutic effect for the pollen allergic rhinitis, and it works maybe through promoting the transition of Th2 to Th1 and regulating the balance of helper T cells.

[Ultrastructure of the digestive system in Dermatophagoides farinae (Acariformes:Pyroglyphidae)].

Fifty living mites (Dermatophagoides farinae) were fixed in 2.5% glutaraldehyde, postfixed in 1% osmium tetroxide, dehydrated in a graded ethanol series, embedded in embedding medium. The ultrastructure of the digestive tract in D. farinae was observed by serial ultrathin sections with a transmission electron microscope. The alimentary canal of D. farinae consists of the cuticle-lined foregut and hindgut separated by a microvilli-lined midgut (anterior midgut, posterior midgut). There are different types of epithelial cells in the anterior midgut The microvilli of epithelial cells in posterior midgut are longer than that of the anterior midgut In posterior midgut, the food bolus is surrounded by the peritrophic membrane. The midgut is the main site of digestion and absorption.