Objectives. NS1 expression of human parvovirus B19 is a critical event in B19 pathogenesis. However, the mechanisms of NS1-induced cytotoxicity in B19 infection have yet to be clarified mainly because of the absence of multifunctional monoclonal antibodies (Mab) against NS1. The purpose of this study was to establish such Mab, which function in immunoprecipitation assays, immunoblotting, indirect immunofluorescence, and immunohistochemical staining.

Methods. Balb/c mice were immunized with the recombinant NS1 protein and hybridoma cell lines producing Mab against the NS1 protein were screened by ELISA, immunoprecipitation, immunoblotting, and indirect immunofluorescence staining. The Mab were used for immunohistochemical staining of formalin-fixed tissues from an intrauterine B19 infected fetus.

Results. ParC-NS1, the monoclonal antibody against the NS1 protein, worked in all tested screening methods. ParC-NS1 could also detect NS1 protein expressed in clinical tissue specimens.

Conclusions. The ParC-Ns1 monoclonal antibody was specific against the NS1 protein. In addition, NS1 protein expression was successfully identified in human tissues. These data indicated that this monoclonal antibody should be a useful tool to study the kinetics and sites of NS1 expression and NS1-induced cytotoxicity in B19 infection.