Objective:Preparation and characterization of monoclonal antibodies against human herpesvirus 6(HHV-6). Methods:Purified HHV-6 was immunized to BALB/c mouse,and the spleen cells of the immunized mouse were fused with SP2/0 myeloma cells. The positive clones which produced McAbs against HHV-6 were screened by ELISA,indirect immunofluorescence assay. And samples of saliva from 25 oral squamous cell carcinoma patients were tested for human herpesvirus 6 by nested PCR assay and ELISA. Results:Clones named as JA9 could secrete specific McAbs against HHV-6 were detected. Isotrip kit of mouse Ig McAbs showed that McAb was IgG1. Culture supernatant and ascitic titres of the antibodies were 1 ∶ 500,1 ∶ 8.0×104,when tested by ELISA respectively. Western-blot showed JA9 was bound to 75 ku protein of HHV-6. HHV-6 positive rates were 60% by nested PCR assay and 40% by ELISA in the salivas of oral squamous cell carcinoma patients. Conclusion:The McAbs against HHV-6 might be a useful tool for fundamental studing of HHV-6 and clinic laboratory detection.