OBJECTIVE To study the binding profile of NV strain SZ9711 (GII-4) with human histo-blood group antigens (HBGAs). METHODS The P domain-encoding fragment was amplified by RT-PCR from the stain SZ9711 and cloned into the pGEX-4T-1 vector. The recombinant fusion protein was expressed in E. coli and purified using the column Sepharose 4B. The P protein was released by thrombin cleavage. The binding of P particles of SZ9711 and VA387 with the HBGAs were measured by saliva-based EIA method. RESULTS The expression of the recombinant fusion protein was shown by the SDS-PAGE, in which a 38 x 10(3)-P protein was obtained. Saliva-based EIA revealed that the P particle of SZ9711 bound to HBGAs in saliva similar to that of the strain VA387 reported previously. It bound strongly to saliva of type A, B and O(secretor) but did not interact with saliva of type O(non-secretor). Noteworthy, binding ability of SZ9711 P particle to type A saliva was lower than that of the VA387 P particle. CONCLUSION This is the first time that a P particle was prepared from a norovirus strain isolated in China and the binding ability of the P particle with HBGAs was analyzed. The result indicated the binding profile of the SZ9711 P particle was similar to that of VA387 reported previously. These data may be valuable in studying the relationship between noroviruses and their bindings to HGBA receptors.