Objective: To develop and evaluate a beads-based light-initiated chemiluminescent assay (LICA) for quantitation of cow milk component (Bos d 5) specific IgG 4 antibody in human serum. Methods: The sIgG 4 -LICA was performed by incubated serum samples with biotinylated allergens, emission beads coated with mouse anti-human IgG 4 antibody and streptavidin-coated sensitizer beads. The reaction conditions of sIgG 4 -LICA were optimized and the analytical performance was evaluated. Results: The precision of intra-assay, within-day and inter-assay (coefficient of variation) were 1.78% to 3.13%, 6.65% to 8.41% and 7.94% to 12.30%, respectively. The functional sensitivity of this assay was 4.71 ng/mL. For the linear range, the sIgG 4 -LICA had a good linear relationship within the range between 28.13 and 1 800 ng/mL, and the linear regression equation was Y=0.98X-1.31(r 2 =0.997). Maximum dilution limit was 1∶64. The disturbing rates measured by adding hemoglobin, triacylglycerol, total bilirubin, acid resistance and biotin to human sera with different concentrations of Bos d 5 sIgG 4 were from -6.38% to 8.60%. Conclusions The sIgG 4 -LICA introduced in this study was demonstrated to have effective performance for quantitation of allergen-specific IgG 4 and can meet the need of clinical requirement.

AIM: To investigate the effect and mechanism of hypoxia inducible factor-1α on intestinal mucosal barrier in sepsis. METHODS: SD rats were randomly divided into 4 groups: sham group, sepsis group, sepsis+HIF-1α stimulant (sepsis+DMOG group), sepsis+HIF-1α inhibitor (sepsis+Bay87-2243 group), 6 rats in each group. Sepsis model was established by cecal ligation and perforation (CLP). The levels of inflammatory markers IL-1β, IL-6, TNF-α, oxidative stress markers MDA and antioxidant factors SOD and CAT were detected by ELISA and the expression of HIF-1α in intestinal mucosa was detected by Western blot. The pathological damage of intestinal mucosa was detected by HE staining. RESULTS: Inflammatory factors, oxidative stress factors and HIF-1α were significantly up-regulated in septic rats (P<0.05). The contents of IL-1β, IL-6, TNF-α and MDA in plasma were significantly decreased by intraperitoneal injection of DMOG (P<0.05); the levels of SOD and CAT in plasma were increased (P<0.05), HIF-1α was up-regulated (P<0.05), and the pathological damage of intestinal mucosa was alleviated, with decreased Chiu's score (P<0.05). Oral administration of Bay87-2243 gave the opposite result. CONCLUSION: HIF-1α has a protective effect on intestinal mucosal injury in sepsis. The mechanism may be related to the alleviation of inflammatory response and inhibition of oxidative stress.