AIM:To investigate the inhibitory effect of heparin-derivedoligosaccharides(Oligs)on secretion of interleukin-4(IL-4)and interleukin-5(IL-5)from human peripheral blood Tlymphocytes(PBTLs).METHODS:Oligs were prepared by three different heparindepolymerization methods and separated by gel filtrationchromatography.PBTLs from ten adult patients withallergic eosinophilic gastroenteritis were treated withphytahematoagglutinin(PHA)and Oligs.The supematantsfrom the cell culture of PBTLs were harvested and subjectedto the determination of IL-4 and IL-5 contents by ELISA method.RESULTS:At the concentration of 5 μg/mL,Oligs withdifferent M_r had different effects on the secretion of IL-4and IL-5.The tetrasaccharide with M_r of 1142,producedby depolymerizing heparin with hydrogen peroxide,hadthe strongest inhibitory effect on the secretion of IL-4.Itdecreased the IL-4 content from 375.6±39.2 ng/L(PHAgroup)to 12.5±5.7 nglL(P<0.01).The hexasaccharidewith M of 1806,produced by depolymerizing heparin withβ-elimination method,had the strongest inhibitory effecton the secretion of IL-5.It decreased the IL-5 content from289.2±33.4 ng/L(PHA group)to 22.0±5.2 ng/L(P<0.01).CONCLUSION:The inhibitory activity of Oligs on thesecretion of IL-4 and IL-5 from human PBTLs closely dependson their molecular structure,and there may be an essentialstructure to act as an inhibitor.The most effective inhibitorsof IL-4 and IL-5 secretion are tetrasaccharides andhexasaccharides,respectively. AIM: To investigate the inhibitory effect of heparin-derived oligosaccharides (Oligs) on secretion of interleukin-4 (IL-4) and interleukin-5 (IL-5) from human peripheral blood Tlymphocytes (PBTLs). METHODS: Oligs were prepared by three different heparindepolymerization methods and separated by gel filtrationchromatography.PBTLs from ten adult patients withallergic eosinophilic gastroenteritis were treated withphytahematoagglutinin (PHA) and Oligs.The supematantsfrom the cell culture of PBTLs were harvested and subjected to the determination of IL-4 and IL-5 contents by ELISA method .RESULTS: At concentrations of 5 μg / mL, Oligs with different M_r had different effects on the secretion of IL-4 and IL-5. The tetrasaccharide with M_r of 1142, produced by depolymerizing heparin with hydrogen peroxide, had the strongest inhibitory effect on the secretion of IL-4.Idecreased the IL-4 content from 375.6 ± 39.2 ng / L (PHAgroup) to 12.5 ± 5.7 nglL (P <0.01). The hexasaccharide with M of 1806, produced by depolymerizing hepar in with β-elimination method, had the strongest inhibitory effect of the secretion of IL-5. It decreased the IL-5 content from 289.2 ± 33.4 ng / L (PHA group) to 22.0 ± 5.2 ng / L (P <0.01) CONCLUSION: The inhibitory activity of Oligs on thesecretions of IL-4 and IL-5 from human PBTLs closely depends on their molecular structure, and there may be an essentials structure to act as an inhibitor. The most effective inhibitors of IL-4 and IL-5 secretion are tetrasaccharides andhexasaccharides, respectively.