[Studies on thermal denaturation of peanut allergen Ara h1 and its interaction with reducing sugars].

The thermal denaturation of peanut allergen Ara h1, its interaction with reducing sugars and the corresponding changes in allergenicity were investigated by circular dichroism (CD), fluorescence and ELISA method comprehensively. The experimental results indicate that the secondary structure of Ara h1 changes significantly along with decreasing alpha-helical structure and its allergenicity with the temperature higher than 85 degrees C, and that both xylose and fructose can stabilize Ara h1 protein structure through interacting with Ara h1 protein and decrease its allergenicity obviously. This study should be helpful to the further understanding of sensitization mechanism of food allergy and be useful for the guidance on reasonable manufacturing of peanut foods.

In vitro refolding process of bovine allergen ß-lactoglobulin by Multispectroscopic method.

OBJECTIVE: To characterize the relationship between the refolding process of recombinant bovine ß-lactoglobulin and its immunoreactivity for clinical purposes. To establish a spectral method which examine the extent of recombinant allergen renaturation. METHODS: The refolding process of recombinant bovine ß-lactoglobulin was investigated by using circular dichroism, fluorescence and synchronous fluorescence spectra. IgE-binding capacity of recombinant protein was analyzed by ELISA. In addition, bioinformatic methods were used to explain the spectral characteristics and analyze the relationship between the conformational changes and the immunoreactivity of the protein during renaturation in vitro. RESULTS: Renaturation of recombinant bovine ß-lactoglobulin resulted in a more compact structure resembling the natural counterpart with stronger IgE-binding capacity. CONCLUSION: The degree of protein renaturation correlated with the IgE-binding capacity of the protein. Results from this study may be of help for food allergy therapy and development of vaccination in the future.

[Spectroscopic studies on the relationship between heat treatment process and immunogenicity of beta-lactoglobulin in milk].

The thermal denaturation of beta-lactoglobulin of milk was investigated by using DSC, circular dichroism spectra, and fluorescence spectra systematically. And its corresponding immunogenicity was tested with ELISA experiments. In addition, bioinformatics methods were also used to explain the spectral characteristics and its corresponding immunogenic change, analyze the conformational changes of the protein during thermal denaturation, and discuss the relationship between conformational change of beta-lactoglobulin caused by heat and immunogenic change. Results from this study should be useful to the establishment of a spectral method examining the extent of thermal denaturation of the food allergen, and be helpful to the understanding of the mechanism of immunogenic change of food allergen treated by heat.

New BZLF1 sequence variations in EBV-associated undifferentiated nasopharyngeal carcinoma in southern China.

The viral lytic gene BZLF1 triggers replication of the Epstein-Barr virus (EBV), which is commonly found in nasopharyngeal carcinoma (NPC). Here, RT-PCR revealed five new BZLF1 variants in 8 of 12 NPC and 4 of 12 non-NPC nasopharyngeal biopsies from an NPC-endemic area in southern China. The deduced peptide sequence of the dominant BZLF1 variant differed by 11 amino acids from that of the prototypical strain B95.8 (V01555). Anti-ZEBRA antibody levels were higher in NPC than that in non-NPC patients (P < 0.001). These findings demonstrated a dominant BZLF1 variant in southern Chinese EBV-associated NPC and non-NPC patients.

Anti-influenza virus effects of crude phenylethanoid glycosides isolated from ligustrum purpurascens via inducing endogenous interferon-γ.

ETHNOPHARMACOLOGICAL RELEVANCE: Ligustrum purpurascens Y.C. Yang (Oleaceae) is traditionally recorded as "Ku Ding Cha", a kind of functional tea in southern China for about two thousand years, which has been reported with sore throat alleviating and pathogenic heat expelling effects. However, there are no scientific studies demonstrating its antiviral activity. THE AIM OF THE STUDY: This study is aimed at investigating the anti-influenza virus effects of phenylethanoid glycosides isolated from L. purpurascens (LPG) as well as its corresponding mechanisms. MATERIALS AND METHODS: In vitro, hemagglutination assay was employed to detect the influenza virus titer; In vivo, C57BL/6J mice were given oral administration of LPG (100mg/kg, 300mg/kg, 900mg/kg) or ribavirin (100mg/kg) once daily for 5 successive days. Meanwhile, on the second day, mice were infected intranasally (i.n.) with A/FM/1/47 H1N1 virus. Mice survival rate and other clinical index were monitored for 15 days. Infected mice were sacrificed to measure the lung lesion and stained with hematoxylin-eosin. Flow cytometry analyses spleen lymphocytes and interferon-γ (IFN-γ) level. The IFN-γ knockout mice (IFN-γ(-/-) mice, C57BL/6J) which had been verified lacking IFN-γ through Western Blot, were applied in the death-protection test to identify the role of IFN-γ played in LPG antiviral effect. RESULTS: In vitro, LPG at 0.5mg/ml inhibited Influenza A Virus H1N1 type (H1N1) infection of MDCK cells. In vivo, LPG at 300 and 900mg/kg significantly decreased the mouse lung index (p<0.05), alleviated influenza-induced lethality and clinical symptoms, and therefore enhanced mouse survival (p<0.05). More detailed experiments demonstrated that antiviral cytokine IFN-γ was involved in the antiviral effect of LPG. Flow cytometric analysis revealed that LPG (900mg/kg) significantly induced secretion of IFN-γ by splenic CD4(+) and CD8(+) cells (p<0.05). Moreover, LPG (900mg/kg) protected wild-type C57BL/6J mice from H1N1 injury, whereas LPG-mediated survival protection disappeared in IFN-γ(-/-) mice. CONCLUSION: These results suggest that up-regulating endogenous IFN-γ by LPG may represent a novel therapeutic approach for H1N1 infection.

The antiviral effects of acteoside and the underlying IFN-γ-inducing action.

There are many herbal teas that are found in nature that may be effective at treating the symptoms and also shortening the duration of viral infections. When combating viral infections, T lymphocytes are an indispensable part of human acquired immunity. However, studies on the use of natural products in stimulating lymphocyte-mediated interferon-gamma (IFN-γ) production are very limited. In this study, we found that acteoside, a natural phenylpropanoid glycoside from Kuding Tea, enhanced IFN-γ production in mouse lymphocytes in a dose-dependent manner, particularly in the CD4+ and CD8+ subsets of T lymphocytes. To this end, we suggest that the antiviral activity of acteoside was highly correlated to its inducing ability of IFN-γ production. Mechanistically, the activation of T-bet enhanced the promoter of IFN-γ and subsequently resulted in an increased IFN-γ production in T cells. Collectively, we have found a natural product with the capacity to selectively enhance mouse T cell IFN-γ production. Given the role of IFN-γ in the immune system, further studies to clarify the role of acteoside in inducing IFN-γ and prevention of viral infection are needed.