[Detection of hepatitis C markers--nucleocapsid protein, RNA and virus-specific antibodies in blood donor plasma].

Comparative study of hepatitis C virus (HCV) markers (core protein, RNA, and virus-specific antibodies) was carried out in plasma samples from 80 donors. A method based on sandwich ELISA with monoclonal antibodies to recombinant protein was developed for measuring core protein. Nucleocapsid protein was detected after various treatments of precipitates obtained after concentration of virus-containing material from plasma samples. These treatments allowed differentiation of core protein in virions, free nucleocapsids, and immune complexes circulating in peripheral blood. The minimal detectable concentration was 5 pg/ml, maximal 850 pg/ml. The detection of core protein virtually coincided with the detection of HCV RNA: 94.4% RNA-positive samples contained the virus protein. Other parameters (activities of antibodies to HCV in ELISA and level of SGPT) did not allow differentiation of plasma samples by the presence of actively replicating virus. Assay of nucleocapsid protein in the plasma of subjects infected with HCV in various populations of virus particles is important from practical (for blood service) and theoretical viewpoints (for studies of virus pathogenesis mechanisms).